US20120058859A1

US20120058859A1 - Automated weightlifting spotting machine

Info

Publication number: US20120058859A1
Application number: US13/254,810
Authority: US
Inventors: Mark Elsom-cook; Michael Escott; Steve Morris
Original assignee: Automorphe Ltd
Current assignee: Automorphe Ltd
Priority date: 2009-03-03
Filing date: 2010-03-03
Publication date: 2012-03-08
Also published as: EP2411099A1; WO2010100493A1; GB0903601D0

Abstract

A weight training assistance apparatus which requires a user to overcome the force exerted by one or more weights comprising: one or more sensors for monitoring a user's activity by monitoring the position of an item indicative of the position of the weights during a weight training exercise; a processor in communication with said sensors; the processor enabled to dynamically compare the user's activity of the item during the exercise with a predetermined activity profile to determine a dynamic level of fatigue for the user; the processor further enabled to determine a response at a given moment based on the exercise undertaken, the current user activity and the determined dynamic level of fatigue; a load bearing device that is controllable by the processor, the load bearing device enabled to dynamically vary the magnitude of the net force exerted by the weight as determined by the response, the processor further enabled to maintain the magnitude of the force when the user's activity is within a predetermined limit of the predetermined activity profile.

Description

TECHNICAL FIELD

The invention relates to an automated spotting machine for weightlifting that applies to both free-weights and stacked weight machines. The device is enabled to provide assistance to a weightlifter when required and to bear the load of weight such as a barbell if a user has reached muscle failure or the exercise has potentially become dangerous.

BACKGROUND TO THE INVENTION

In weight training it is known for the weightlifter to ask for a spotter to monitor the exercise and to provide assistance to the weightlifter when required. The assistance provided may involve taking the whole weight to avert a dangerous situation when using free weights or to assist with a lift using free weights or stacked weight machines, allowing the weightlifter to continue with an exercise so that they may complete more repetitions than they would normally do without assistance (forced repetitions). The assistance of a spotter also allows the weightlifter to perform negative repetitions where the spotter lifts the weight to the starting position and the weightlifter then slowly lowers it whilst being monitored. A spotter may also help the weightlifter perform ‘drop sets’ where once failure has been reached at a given weight, weights are removed to allow the exercise to continue.
In order to achieve the most effective method for building muscle mass, the lifter should be at the limit of their lifting ability for a period of time during an exercise session. This limit will vary during the session since the lifter will progressively fatigue muscle, becoming weaker and more tired as the session progresses.
Without a spotter, the lifter will reach the ‘failure’ point, at which they cannot complete a lift, but a spotter can take part of the weight to extend this point so that the lifter can complete more repetitions (reps). It is also known for a lifter who has reached fail to normally complete additional assisted reps, example forced or negative reps.
A disadvantage of free weight training is that a spotter is not always available and subsequently the user may not partake in free weights or does so without a spotter, which is potentially dangerous. Self spotting devices are known in the art but these rely on the weightlifters input to provide assistance. For example U.S. Pat. No. 5,823,921 requires the user to engage a foot pedal to initiate the spotter and is subsequently complex to use.
Another disadvantage of many of the self spotting weightlifting machines is that they only act as a safety device, and are unable to provide assistance to the weightlifter to help them complete a repetition as is required for human spotters.

SUMMARY OF THE INVENTION

The invention seeks to avoid or at least mitigate these and other problems in the prior art, the present invention provides an apparatus for a weight lifting machine, which is able to provide assistance to a user as well as acting as a safety mechanism.
The spotting device is an electro-mechanical system, which can replicate the role of a human ‘spotter’ in a free weights environment. This entails being able to take the full weight of the bar if the lifter is unable to hold it (hence acting as a safety feature) and slightly easing the weight when the lifter is on the limit of their strength.
In an embodiment of the invention, the main focus is on the latter part of the task. In the present invention, a key aspect is detecting the level of fatigue and providing the right amount of support to keep the lifter making maximum use of the muscles. Without a spotter, the lifter will reach the ‘failure’ point, at which they cannot complete a lift, but a spotter can take part of the weight to extend this point so that the lifter can complete more repetitions (reps).
The spotter will use the first rep as a calibration rep, or offer the user the option of performing a calibration rep. The lifter engages the spotter with a predetermined activity profile, by entering their personal profile and/or enters initial calibration data. Once the apparatus has been calibrated, the lifter performs their exercise, which is monitored by one or more sensors. A processor is enabled to determine the lifter's need for assistance and actively support some or all of the weight if required.
In one aspect of the invention there is provided a weight training assistance apparatus comprising a sensor for monitoring a user's activity during weight training exercise, a processor in communication with the sensor adapted to compare the user's activity during the exercise with a predetermined activity profile and to determine the user's need for assistance, the processor being further adapted to control a load bearing device thereby to assist the user during weight training.
According to another aspect of the invention there is provided a weight training assistance apparatus which requires a user to overcome the force exerted by one or more weights comprising: one or more sensors for monitoring a user's activity by monitoring the position of an item indicative of the position of the weights during a weight training exercise; a processor in communication with said sensors; the processor enabled to dynamically compare the user's activity of the item during the exercise with a predetermined activity profile to determine a dynamic level of fatigue for the user; the processor further enabled to determine a response at a given moment based on the exercise undertaken, the current user activity and the determined dynamic level of fatigue; a load bearing device that is controllable by the processor, the load bearing device enabled to dynamically vary the magnitude of the net force exerted by the weight as determined by the response, the processor further enabled to maintain the magnitude of the force when the user's activity is within a predetermined limit of the predetermined activity profile.
Further aspects, features and advantages of the present invention will be apparent from the following description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described by way of example only, with reference to the following drawings, in which:

FIG. 1 is a schematic perspective view of an apparatus in an embodiment of the invention;

FIG. 2 is a schematic side elevation of the apparatus shown in FIG. 1;

FIG. 3 is a schematic of the spotting mechanism;

FIG. 4 is an example of a distance versus time graph of a single rep;

FIG. 5 is an example of a velocity versus time for a single rep;

FIG. 6 is an example of a acceleration versus time graph for a single rep;

FIG. 7 is a flow chart of the process of the spotting mechanism in use;

FIG. 8 is a schematic perspective view of an apparatus according to a further embodiment of the invention; and

FIG. 9 is a schematic end elevation of an apparatus according to yet another embodiment of the invention.

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

FIG. 1 shows an embodiment of the invention, in which there is shown apparatus 10, bench 12, rack 14, barbell 16, vertical support 18, pulleys 20, and 24, horizontal support 22, groove 23, motor 42, brake 26, motor 25, control panel 28, cable 30, barbell attachment means 32, sensor 34, reflective strips 36, sensor 40, sensor 44 and processor 38 (located inside control panel 28).
The apparatus 10 shown in FIG. 1 is a variation of bench press apparatus. The bench 12, rack 14 and barbell 16 are all standard pieces of equipment. The invention comprises the addition of the vertical support 18 and horizontal support 22 which define a structure, which preferably extends over the bench 12. Pulleys 20 and 24 are attached to the horizontal support 22 and pulley 24 is preferably moveable along the grove 23 powered by motor 25. A motor 26 is attached to vertical support 18 and the cable 30 runs from the motor 26, through brake 42, along the vertical support 18, over the pulley 20 along the grove 23 and pulley 24 and is attached to the barbell 16 via the barbell attachment means 32. The barbell 16 further comprises reflective strips 36 which allow sensors 40, to sense the barbells vertical position. The sensor 34 moves along the groove 23 to enable calculation of the horizontal position of the barbell 16 and allows the pulley 24 to maintain position above the barbell 16. Sensor 40 enables calculation of the position of the barbell 16. The sensor 34 and sensor 40 are linked to a processor 38, which is preferably integrated into the control panel 28, attached to the vertical support 18. A control panel 28, which is enabled to display information and allow a user to input information is also integrated into the vertical support 18. Pulley 24 and sensor 34 move along the groove 23 by means of a motor 25. The term user and lifter are used interchangeably during the course of the specification, and they represent the same person.
The cable 30 is attached to the barbell 16 at barbell attachment means 32. The barbell attachment means 32 are preferably releasable allowing the barbell 16 to be detached from the apparatus and another form of bar to be attached. The cable 30 runs from the barbell 16 to pulley 24, along the horizontal support 22 through pulley 20, down the vertical support 18 and through the brake 42 to the motor 26. The motor 26 houses the excess cable 30 and in the preferred embodiment the motor 26 provides some resistive force to the cable 30 thereby keeping the cable 30 taut. However, the amount of resistive force applied is only sufficient to keep the cable 30 taut to ensure that the cable 30 does not bear any of the load of the barbell 16. The cable 30 is made from any suitable material that has sufficient strength to be able to withstand a load of a barbell 16, preferably steel wire. For safety reasons, the cable is preferably able to support several hundred kilos.
The motor 26 in the preferred embodiment is a servomotor though other forms of motor may be used. The motor 26 is enabled to be able to provide sufficient power to lift the barbell 16, by retracting the cable 30, which is preferably stored in the housing of the motor 26. In the preferred embodiment, the motor 26 is attached to the vertical support 18. In further embodiments (not shown) the motor 26 may placed elsewhere, for example, below the bench 12. A braking mechanism such as a drum type brake is preferably provided within the motor 26. An additional brake 42 is provided for additional safety.
The motor 26 therefore is enabled to reduce the net force exert by the weights. Under normal use, the net force of the weights will be the weight (i.e. mass times gravity). When the motor 26 is engaged magnitude of the net force exerted by the weights is reduced by an amount related to the strain taken by the motor. For example, if a barbell 16 has 100 Kg of weight and the cable 30 is taut but not bearing any weight the net force exerted by the weight will be 100 Kg. If the motor 26 is engaged and provides a force of 20 Kg then the net force exerted by the weights is 80 Kg. Therefore, the magnitude of the net force exerted by the weights can be varied by the motor.
The control panel 28, is enabled to allow the weightlifter to input details regarding themselves e.g. height, weight, arm reach etc., and/or the exercise they wish to undertake e.g. weight of the barbell 16, number of repetitions, forced or negative repetitions etc. Preferably the control panel 28 is a self-contained unit of the class typically referred to as a Mobile Data Terminal (MDT) It consists of a computer with storage, interface cards and a touch screen. It will be operated through a Graphical User Interface (GUI). This device is similar to those found in-car GPS systems.
In a further embodiment the control panel 28 has other data input means e.g. USB socket, mobile phone, voice input, swipe card, key fob etc., which allow the user to identify themselves by some form of external input.
The apparatus also contains a number of sensors 34, 40 for calculation of speed and location of the barbell. In the preferred embodiment there are one or more sensors on rack 14 and one or more sensors 34 located in the groove 23. In the preferred embodiment the sensors 34 in groove 23 are infrared sensors and sensors 40 are infrared or ultrasonic distance measuring sensors. The sensors are preferably contactless sensors, that is to say that they measure the position. The strength of the signal between the sensors 34 and 40 allows for a calculation of the position of the barbell and therefore barbell 16 relative to the vertical support 18. Preferably to increase the accuracy of the positional determination of the barbell 16 there at least two sensors 40 on the rack 14 and at least one sensor in groove 23.
The sensors 34, 40 may also measure the speed of the cable 30. Preferably there is a barbell sensor 40. In the preferred embodiment the sensor 34 on the horizontal support 22 and the barbell sensor 40 are infrared sensors enabled to calculate the distance between the sensors 34 and 40. As the sensor 34 is fixed and barbell sensor 36 would move the position of the barbell 16 may be calculated. Other suitable sensing means for detecting the position of the barbell 16 with respect to the vertical support 18 may also be used.
All sensors are preferably contactless sensors, that is to say that they measure the position of the bar in a 3-D environment without the need for a physical connection between the measuring sensor and the bar. The sensors can be used to measure the barbell 16, the weights lifted, the lifting arm etc. The sensors therefore measure the position of an item (e.g. the barbell, the weights, a reflective strip placed on the weights or barbell etc) which provides an indication of the current position of the weights during exercise. The sensors are preferably one or more of known infra-red, ultrasonics or laser based sensors
The information from sensors 34, 40 is transmitted to processor 38, which is preferably a suitable known microprocessor. The processor 38 is preferably integrated into the control panel 28 and is enabled to calculate the position of the barbell 16 with respect to the vertical support 18 from the strength of the signals received from the sensors 34 and 40. To accurately measure the position the sensors use triangulation techniques to accurately measure the position of the barbell 16.
In a further embodiment, there are additional sensors in the horizontal support (not shown in FIG. 1) which are used to increase the accuracy of the positional measurement.
The processor 38, preferably, is linked to some form of writeable memory so that it may store information regarding multiple users. The writeable memory may also contain information regarding the user and exercise programme that they are undertaking therefore reducing the amount of information that needs to be inputted at the control panel 28.
FIG. 2 is a side revelation of FIG. 1 and shows the features as described with respect to FIG. 1. A brake 42 and a cable speed sensor 44 on the vertical support 18.
A brake is preferably housed in the motor 26, but in a preferred embodiment there is a further brake 42 on the horizontal support 18. The brake 42 is preferably a drum brake, though other types of brake may be used. The brake is enabled to stop the cable 30 and is able to support all the weight of the barbell 16.
FIG. 3 shows a schematic of the control system of the spotter. There is shown the GUI 50, which inputs data to a processor control 52. There is also shown position sensors 54 and cable tension sensors 56 which inputs information to the processor control 52, a brake control 60 which receives information from the processor control 52 and an engine control 58 and memory 62 which both receive and input data to the processor control 52.
As discussed previously, the control panel 28 is preferably a GUI 50 which is enabled to display information and has a touchpad means to allow a user to input further information. In a further embodiment the information may be inputted remotely e.g. via a wireless connection, or via some form of user identifier such as a swipe card, key fob etc. The information inputted at the GUI 50 is passed to the processor controller 52.
In a preferred embodiment the controller 52 accesses the memory 62 for any relevant saved data, for example regarding the user, the exercise to be undertaken. The processor control 52 is preferably further enabled to write to the memory 62 so that any information inputted at the GUI 50 may be stored for further reference.
In the preferred embodiment, the processor control 52 receives information from the position sensors at least 10 times per second, and preferably between 100-1000 times a second. The information, in the form of signal strength allows the processor control 52 to calculate the relative position of the barbell 16 (not shown in FIG. 3) at that particular moment. The processor control 52 stores the different positional information over time and therefore can also calculate the speed and acceleration of the barbell 16. The position and speed of the barbell 16 are evaluated and if they are outside the accepted tolerances and decision is made as to whether the brake 42 and/or motor 26 should be engaged. The decision as to whether the position and/or speed are outside the accepted tolerances is discussed with reference to FIG. 4.
If processor control 52 determines the speed is above an acceptable limit, the processor control sends a signal to the brake control 60, which engages the brake 42 (not shown in FIG. 3).
If processor control 52 determines the motor 26 should be engaged, the amount of load the motor should bear is calculated by the processor control 52 (The calculation of the load born is discussed with reference to FIG. 4) and a message is sent to the engine control 58 to wind in the cable 30 to bear the correct amount of load. The speed sensors 54 feedback to the controller 52 which in turn feeds back to the engine control 58 to either increase or decrease the load on the cable. With such a feedback loop it is desirable to use a servomotor as the motor 26.
In the preferred embodiment the cable 30 is kept taut at all times to minimise the time for the motor 26 or brake 42 to be properly engaged. In further embodiment the cable 30 is slack and a cable tension sensor 56 is required. Such a sensor is required to allow the processor control 52 to compensate for the slackness in the cable 30. For example if a user drops the weighted barbell 16 the speed sensors 54 would register the increase in speed which would be flagged as dangerous the controller 52 which would engage the brake 42 via the brake control 60. If the cable 30 is slack the barbell will fall further than if the cable 30 were taut. To compensate the controller 52 would, for example, engage the engine 58 until such time as the tension sensor 56 would register the cable 30 as being taut.
In the preferred embodiment the characteristics of freefall will be programmed in, so releasing a weight altogether will automatically apply the brake. Also, each site can set a minimum height above the bench below which the weight will not be allowed to go. These additional features are designed to increase the safety of the user.
In use, a user inputs the details of the exercise they wish to perform including the weight on the barbell 16 and number of repetitions, and details regarding themselves e.g. height, arm length into the control panel 28.
In a further embodiment the user inputs a unique ID, which will identify the user, and retrieves previously inputted information about the user from a writeable memory 62. The ID preferably also identifies a training programme for the user and displays the programme to the user at the control panel 28 via the GUI 50. The user indicates via the control panel 28 if they wish to accept the suggested exercise or another exercise. If the user does not have an ID, the details of the user are preferably stored on the memory 62 so that the information may be retrieved upon any subsequent use.
In another embodiment the user does not input any information into the control panel and the apparatus is calibrated to the user at the start of the exercise. The calibration in requires the user to perform a single or multiple presses, where the sensors 34, 40 calculate the maximum height of the barbell 16 during the press which corresponds to a full extension of the user's arms, and the speed of the lift (during both ascent and descent). The sensors 34, 40 preferably also record information regarding the height of the barbell 16 through the press, as well as the time. This allows the processor to construct a model height versus time graph for an individual press. The sensor information would also be used to construct graphs of various parameters, e.g. acceleration versus time. These graphs are discussed in further detail with reference to FIGS. 4 to 6.
After input of the data and/or calibration the user performs their exercise in the normal manner e.g. bench press. Sensors 34 and 40 measure the position of the barbell 16 and cable speed sensor 44 measures the speed at which the barbell 16 is being moved. The sensors 34, 40, 44 send their readings to the processor 38, which uses triangulation techniques to determine the relative position of the barbell 16.
The speed and positional information is used to determine if the processor control 52 is required in engage the brake control 60, to bear all the weight (i.e. the weights exert zero net force) or engine control 58 so that the net force exerted by the weights is reduced. The method and process of determining the course of action and the response is discussed in further detail with respect to FIGS. 4 to 6.
FIG. 4 shows an example of a typical height versus time graph for a single lift.
There is shown the distance S, along the y-axis and time t along the x-axis. The lift is divided into seven stages A,B,C, D, E, F and G.
These seven stages represent, the lifter performing the following actions:

- A. Accelerating the bar from rest to a maximum velocity;
- B. Extending arms at maximum velocity;
- C. Decelerating to lock position at full extension;
- D. Holding the bar at full extension;
- E. Accelerating to a maximum descent velocity;
- F. Holding the fixed velocity for descent; and
- G. Decelerating to zero velocity at the rest position.

The graph is constructed from the sensor information of the various sensors 34, 36 placed on the apparatus. The processor 38 is enabled to determine the position of the barbell 16 at various time intervals. Therefore the processor 38 has position and time data for the barbell 16, and the construction of the graph is implemented using standard methods. In the preferred embodiment, the graph is calculated with a relative position, the baseline being the rest position assumed between reps.
From this graph and the associated velocity versus time and acceleration versus time graphs the performance of the user, or lifter, may be determined and a decision as to whether to the user requires assistance, and the extent of assistance may be made.
The simplest measurement is distance (S). There is a minimum value (S0) which is the rest position, which corresponds to the lowest position of the barbell in a single press. Typically, in a bench press this would be a couple of inches above the user's chest.
There is also a maximum value (SMax), which represents the position for the arms at maximum extension. The values of S0 and SMax will differ according to each user and their lifting styles.
The absolute detail of the shape will also vary between lifters, and even varies between exercises for the same lifter, however, the general shape and the seven stages are consistent across all weightlifters.
As mentioned previously, there is, for a given lifter, a ‘Calibration rep’ which is stored in the system (this may, in fact, be the average over a number of reps). This represents the optimum performance of that user, carrying out a single lift when they are unfatigued. Preferably, the calibration rep is performed at the start of each session, as the performance of a user may change over time. In further embodiments the Calibration rep is stored from previous instances of the user.
The Calibration rep, is known to change between sessions, and within one session represents the optimum behaviour of the user. In an embodiment of the invention, the first rep of the user is used as the calibration rep, and the user immediately commences their exercise set.
The spotter detects the onset of fatigue (and hence decides on the level of assistance) by comparing various parameters of the Calibration rep with the actual performance on a given rep.
The parameters used can be grouped by measurement and stage, where the measurement is either S (distance), V (Velocity) or A (acceleration).
FIG. 5 shows a typical velocity vs. time graph for a single rep. The seven stages A to G are equivalent to those described in FIG. 4.
FIG. 6 shows a typical acceleration vs. time graph for a single rep, with the same seven stages as described above.
From the graphs shown in FIGS. 4, 5 and 6 one or more of the following parameters are determined by the processor 38.
SMax—full extension measured in StageD;
TMax—length of time weight is held at full extension in Stage D, which are determined from the height versus time graph (FIG. 4).
Vup—velocity achieved in Stage B; Vdown—Velocity achieved in Stage F, from the velocity versus time graph (FIG. 5).
AA—acceleration to maximum lifting velocity (as measure in stage A); AC—deceleration at end of lift (as measure in stage C;) AE—acceleration to descent velocity (as measure in stage E); AG—deceleration to rest (as measure in stage G), these are all measured from the acceleration versus time graph (FIG. 6).
The system maintains two variables for the distance, which describe permissible variation in the parameter, these are:

- ΔPN—the normal variation in this parameter which does not indicate any fatigue; and
- ΔPF—the failure variation of the parameter which indicates that the lifter has passed their limit.

An example of the use of ΔPN and ΔPF is given using the velocity Vup, the measured velocity in stage B. From the calibration lift a value of Vup, where the user is assumed to have zero fatigue is calculated. This value of Vup is expected to decreased during the exercise as the user becomes fatigued.
By comparing the actual value of Vup to the calibration value of Vup a value of ΔVup may be determined. The preferred method of determining ΔVup is:
ΔVup=(Vup _calib −Vup _actual)/Vup _calib
where Vup_calibis the speed of the press in the calibration press and Vup_actualis the speed during the exercise. Other methods for determining ΔVup such as the absolute difference between Vup_caliband Vup_actualmay also be used.
In the preferred embodiment the processor 38 uses look up tables to determine a course of action based on the value of ΔVup. For example if the value of ΔVup is 0.1 this would indicate that the user is performing the lift 10% slower than during the calibration rep. Such a value in the look up table would be marked with ΔVupN or ΔPN i.e. that the user has not reached failure. Accordingly the processor 38 would continue monitoring the exercise and allow the user to continue as normal.
If at a later time, say after the 10th rep, the value of ΔVup is 0.66, this would indicate that the user is becoming fatigued and may require assistance. In this example the look up table for 0.66 would read ΔVupF or ΔPF i.e. the user has reached failure and requires assistance. The process of assisting the user is described below with reference to FIG. 7. The above measurement of the variation between the model and the actual behaviour and the monitoring of the values of ΔP may be applied to one or more the parameters listed above and not just Vup. Additionally, the look-up tables may be tailored to the individual user, depending on the extent of the exercise they wish to do, with the values of ΔPN and ΔPF changing accordingly.
In a further embodiment, the profiles that are stored in the writeable memory 62 also contains a “problem pattern” library. The library contains profiles which are indicative of current types of “non-ideal” lifts. The term non-ideal relates to where a lift is not performed in the idealised manner, for example, where one arm is favoured over another arm, the barbell 16 may rotate slightly. By analysing the performed exercises against the “problem library” the invention is able to identify if any lifts are being performed incorrectly. Preferably, the invention is able to communicate this to the user by way of the GUI 50.
FIG. 7 is a flow chart of the process of the spotter algorithm that the controller 52 uses to evaluate if a user requires assistance. There is shown the monitoring the speed and position at step S100, updating the various graphs at step S102, calculating the value of ΔPN and ΔPF at step S104, determining if the user requires assistance at step S106, engaging the motor and or brake at step S108, The monitoring of the speed and position of the barbell 16 at step S100 is performed using the various sensors 34,40, 44 which inputs the data to the processor 38. The processor 38 determines the position of the barbell 16 as well as the time. The information is stored in the processor during the exercise.
The monitoring of the speed and position of the barbell preferably occurs at least 10 times a second and preferably between 100-1000 times a second for safety reasons. This allows for any potentially dangerous situation to be quickly identified, and the apparatus to react to prevent any injury to the user.
Using the information recorded at step S100, the various graphs are updated at step S102. In the preferred embodiment, the graphs that are updated are the distance vs. time, velocity vs. time and acceleration vs. time graphs. From the position and time information the updating of the graphs is readily implemented by the processor 38.
Using the updated graphs from step S102 the values of AP, where P is parameter e.g ΔVup, are updated at step S104. The determination of the values of ΔP is as described above.
Once the values ΔP has been determined it is compared to the value of the look up table at step S106. If a value of ΔPF is returned it is an indication that the user has reached muscle failure or is fatigued and therefore requires assistance, the process goes to step S108. If ΔPN is returned the user is within the acceptable limits and the process returns to step S100 and repeats until failure has been reached or the exercise is finished. By monitoring the speed and position several times a second, values of ΔP may be dynamically updated. i.e. they are updated whenever a measurement is taken. Therefore, measures of fatigue and failure may be dynamically determined during user exercise. Preferably step S106 is performed upon each measurement of the position of the weights by the one or more sensors, and therefore occurs at least 10 times per second, preferably more. Therefore the apparatus may be considered to be dynamically varying the weight, in that the variations occur at a rate such that the user is unable to notice a pause between operations.
If the user requires assistance the amount of assistance required is calculated and the motor and/or brake is engaged at step S108.
The amount of work performed by a user during a single lift is proportional to the area under a distance versus time graph, as shown in FIG. 4. Such work may be represented as a power curve for the exercise. The power curve varies with the amount of power required for the exercise at a given time. e.g. More power is required at the start of a lift than say at the top of the lift. Power curves will vary for each user and for the exercise undertaken. In a further embodiment fatigue and muscle failure may be measured using the power curve profile.
If the user requires assistance the speed of the lift is below the accepted tolerance the amount of load to be taken by the cable is calculated as being proportional to the weight on the barbell 16 and the difference between the area under the graph of the model graph and the actual graph. So if the actual relative height of the barbell 16 is much lower than the expected height the difference of the areas would be large and the processor control 52 would send a signal to the engine control 58 to increase the power of the motor 26 thereby increasing the load on the cable and reducing the net force exerted by the weights.
When the system detects fatigue it has the option depending upon user preference, to engage one of four exercise regimes: 1 forced reps; 2 negative reps; 3 drop sets; 4 partial reps.
For all types of additional reps the user will have reached the point of positive muscular fatigue.
Forced Reps;
Forced reps require a training partner to provide just enough assistance to keep the weight moving. This continues for the desired amount of repetitions.
The equivalent behaviour for the invention is as follows. The invention tracks the behaviour of the user to determine if they are in a fatigue zone (as described below). If they are fatigued then the system lifts just sufficient weight from the bar to enable the user to keep operating without entering the failure zone. The invention continually monitors and re-calculates the required assistance during the exercise thus keeping the user at the edge of positive muscle failure. Therefore, the motor dynamically varies the net force exerted by the weights through the motor until the user is within the limit of positive muscle failure.
If the user is found to be in the failure zone the weight is dynamically reduced until such time the user is able to lift the weights and they are no longer considered to be failing. Once the user has reached the fatigue zone (i.e. moved out of the failure zone) the motor maintains the net force so that the user may continue the exercise with weights exerting a reduced net force.
This is continued until the desired number of reps are completed.
Negative Reps;
Negative reps require a training partner to lift the weight to the start position at maximum extension (SMax). The user simply lowers the weight as slowly as possible. When the user reaches the bottom of the movement, (SMin) the training partner will raise the weight again. This continues for the desired amount of repetitions.
The equivalent behaviour for the invention is as follows. The invention automatically raises the weight to the maximum extension (SMax) for this user by engaging the motor 26 to take the full weight of the barbell 16. The user then takes the weight of the barbell 16 and lowers it to their minimum position (SMin). The invention tracks this behaviour and provides safety feature to lift the weight if it is being lowered in an uncontrolled manner. At the bottom of the rep it lifts the weight to the top and repeats until the desired number of reps are completed.
During descent, as with the forced reps scenario, if the user is found to be beyond the limit of positive muscle fatigue the motor will dynamically reduce the net force exerted by the weights until the user is determined to be within the fatigue zone. As with the force reps once the user has moved back into the fatigue zone the net force exerted is maintained.
Drop Sets;
For drop sets the user performs a set of any exercise to failure or a point just short of failure. At this point the weight is reduced and the user continues for more repetitions with the reduced weight.
The equivalent behaviour for the invention is as follows. The invention tracks the behaviour of the user until the fatigue zone is entered. At this point it reduces the weight by a pre-determined percentage and continues to track the user as with normal reps. The pre-determined percentage may be user inputted when initialising the apparatus or it may be a set percentage. The dropped weight may be by either physically changing the weights on the barbell 16 or using another barbell 16, or by engaging the motor 26 to bear the pre-determined weight during the lift.
As with the forced rep scenario, if the user is unable to maintain their exercise level with the dropped set (i.e. stay within the limits of positive muscle failure) the motor will dynamically reduce the net force exerted by the weight until the user is able to perform their exercise at the predetermined acceptable level.
Partial reps
Partial reps occur when the user intentionally completes less than the full extension for a rep while using a given weight on the bar. The partial is typically the top part or the bottom part of the normal full rep. The user will decide how much of a rep to complete and whether it is top or bottom. Typically, the partial rep will be inputted into the control panel by the user at the start of the exercise. In a further embodiment the partial rep to be performed will be stored in the user's profile.
When performing a partial rep with a human spotter the exercise occurs as follows. If the top part of the rep is to be completed the training partner holds the bar at the starting position. The user lifts from there to the top of the rep in an unassisted manner, and then returns the weight to where it started, at which point the training partner takes the weight from them. If it is the lower part of the rep then the user starts from their normal SMin and lifts until the spotter tells them that they have reached their desired extension.
The equivalent behaviour for the invention is as follows. The invention can be configured to provide either Upper or Lower partial reps. The user must choose the type of rep and the range of the rep (i.e. the distance between bottom and top of the rep).
For upper partial reps, the invention moves the weight to a position which is below SMax by the value of range of the rep. The user takes the weight, lifts it to the top and lowers it. When the weight reaches the position which is below SMax by the value of range, the invention takes the full weight.
For lower partials, the system treats the rep like a normal rep, except that it takes range, rather than SMax to be the top of the rep. In the preferred embodiment there is an auditory confirmation, such as a siren, is used when this position is reached.
In a further embodiment the look up tables are used to determine the amount of assistance required. From the example of ΔVup in FIG. 6, ΔVup was 0.66, the look-up table also contains an indication of how much weight should be beared by the cable 30 and motor 26. The value of 0.66 would indicate that whilst the user is tired they still have not reached total muscle failure and accordingly the motor 26 and cable 30 will take 10% of the total weight of the bar. The higher the value of ΔVup, the more fatigued the user and therefore the greater the weight born. As a safety aspect if the value of ΔVup reached 80% the motor and cable would take the entire weight of the barbell 16 as the user would have reached a dangerous level of muscle failure and may potentially lose control of the barbell 16. Again the value of the percentage of weight to be taken by the motor as defined in the look-up tables may be varied.
The power supplied by the motor 26 is, in a preferred embodiment constantly adjusted, to take into account the user performance when the engine is engaged. The values of ΔPN and ΔPF are re-calculated whilst the assistance from the motor 26 occurs. If the value of ΔPN is found to return to within the acceptable limits it would indicate that the correct amount of assistance is being provided and that level of assistance is maintained. If the value of ΔPF increases whilst the motor 26 is engaged, it would indicate that the user requires further assistance and the processor control 52 would send a signal to the engine control 58 to further increase the power supplied. The level of assistance (i.e. reduction in net force) is increased until such time that the user is within the pre-determined zone e.g. the values of ΔPN and ΔPF are within the acceptable limits. Once the user is within the acceptable limits then the present level of assistance is maintained.
Drop Sets;
In yet another embodiment of the invention, if the user is found to require assistance the apparatus may enter “drop weight” mode. Once the user has reached failure on a particular weight set, the rep is completed and the barbell 16 returned to the rack 14. Weights are then removed from the barbell 16, and a further set of reps are completed using the lower or dropped weight set.
In yet another embodiment of the invention, if the user is found to require assistance the apparatus may enter “drop weight” mode. Once the user has reached failure on a particular weight set, the rep is completed and the barbell 16 returned to the rack 14. Weights are then removed from the barbell 16, and a further set of reps are completed using the lower or dropped weight set.
In a further embodiment, the motor 26 is used to simulate the removal of the weight from the barbell 16, during the “drop weight” mode. In this embodiment, the cable 30 is kept taut and the motor 26 is engaged to bear some of the load of the barbell 16. For instance, a user completes 20 reps using a 60 kg weight, and is found that their value of ΔPF indicates that they have reached fail after 10 reps. The motor 26 is engaged and supplies sufficient power to constantly lift 10 kg. Therefore the motor 26 has effectively reduced the weight on the barbell 16 to 50 kg. The user continues with their reps and is found to fail, from their measured value of ΔPF after a further 5 reps at 50 kg. The motor 26 increases the load born by a further 10 kg, effectively making the weight on the barbell 40 kg. This allows the user to complete their exercise without having to rack the barbell and remove some weights, as would occur when normally performing free-weight exercises. The setting of the drop weight mode is preferentially preformed at the control panel 28, where the increments in the reduction of weight may be set, though it may also be activated as part of a user profile stored in the writeable memory 62.
A further indicator of a user requiring assistance is if the relative height of the barbell 16 begins to decrease before maximum extension is reached. This indicates that the user has reached muscle failure and the processor control 52 is required to engage engine control 58 as a safety feature. The load that the cable 30 would bear in this situation in an embodiment is calculated by the value of ΔPF. In a further embodiment the power of the motor 26 and therefore the load beared is taken as being proportional to the weight of the barbell 16 and the difference between maximum height achieved and the maximum expected height. Again, if the difference is large the processor control 52 increases the power of the motor 26 thereby increasing the load on the cable and reduces the net force exerted by the weights.
The motor 26 is engaged at step S108 winding in the cable 30 to take the load as required. Once the motor 26 is engaged the speed and height of the barbell 16 are continually monitored. If, in the case of the speed falling below a set tolerance, the difference in the area between the model and actual graphs increases, it would indicate that more assistance is required and the motor 26 increases its load borne. If the speed increases to above the expected speed the load bared by the motor 26 will decrease, as it would indicate that the user requires less assistance. Therefore, once the motor has been engaged to vary the net force exerted by the weights, the process returns to step S106 to monitor the user's exercise. If the user is still found to require assistance at step S106 the process repeats until the user is found to be within an acceptable limit of the predetermined user profile. Therefore, the power exerted by the motor 26, and therefore the reduction in the net force, is continually varied until such time the user is within an acceptable limit i.e. is found not to require assistance as determined at step S106.
As a further safety mechanism, if the barbell 16 is travelling downwards the speed at which it is travelling is checked against a maximum safe speed and preferably acceleration. Given the position and time information the processor is able to measure the speed and acceleration of the barbell 16. If the barbell 16 exceeds the maximum safe speed or acceleration it would indicate that the user is unable to control the barbell 16 and the controller 52 engages the brake. Preferably as well as engaging the brake the motor 26 will also be engage to lift the barbell 16.
In yet another embodiment, further monitoring of the user may also occur by measuring the rise time, sections A, B and C of FIG. 4, the fall time sections E, F and G of FIG. 4 and the pause time which is simply the period of time between reps. As a user completes more repetitions it is found that the pause time increases as the user becomes fatigued. If the pause time is measured to increase to a level greater than expected, this would be taken as an indication that the user may require assistance. In an embodiment of the invention there is a maximum pause time which if exceeded would automatically engage the motor 26. The maximum pause time may be set by the user at the control panel 28 when initialising the invention or be a default setting of 20 seconds.
Other free-weight exercises will have different shaped graphs, and the processor 38 would react according to these graph shapes. In a further embodiment the graph shapes for the individual users are stored on the writeable memory 62 allowing the processor 38 to compare the height and speed against previous user data rather than model data. If a model height versus time graph is used it would be stored in the memory 62 and preferably accessed by the processor 38 during the initialising of the apparatus 10.
In a further embodiment of the invention the control panel is enabled to accept voice commands. As well as monitoring the user in the manner described above the invention may accept commands from the user such as “Spot” or “Help” to engage the motor 26 and “more” or “less” control the amount of load to be supported by the motor. This embodiment relies on standard voice recognition techniques to determine that assistance is required.
Whilst the present invention has been described with respect to the bench press exercise as shown in FIG. 1, those skilled in the art will understand that the present invention need not be limited to the bench press but is also applicable to all other forms of free weightlifting such as an inclined barbell press, dumbbell flyes, standing barbell press, dead-lifts etc, as well as stacked weight machines and physiotherapy equipment where the weight taken by the invention is that of the users limb or body. Other weight exercises and applications will have different shaped graphs, but the processor 38 calculation of ΔPF and ΔPN would be performed in an identical manner, of using a calibration rep and comparing the actual data to the calibration data and making decisions based on the comparison as described above.
FIGS. 8 shows a further embodiment of the apparatus. There is shown the features of the apparatus as described in FIGS. 1 and 2.
In this embodiment there are two motors 26, each with pulleys 20 and cable 30. The cables 30 are attached at opposite ends of the barbell 16. In this embodiment, the motors 26 are configured to provide different amounts of support on each side of the barbell 16. This may be required when one of the user's arms reaches fatigue or failure before the other. The method for determining if a user is reaching fatigue or failure is as described above.
In a preferred embodiment, the processor also places a limit on the differential between the supporting forces provided by each motor 26 thereby ensuring that the user does not preferentially use one arm over another.
FIG. 9 shows yet another embodiment of the apparatus. There is shown the features of the apparatus as described in FIGS. 1 and 2. There is also shown a track 51.
The vertical supports 18 are moveable along the tracks 51. The supports 18 are moved using a pulley and cable system (not shown) though other methods may be used. Depending on the exercise to be performed the tracks 51 may be positioned to move the vertical supports 18 in the direction of the exercise. For example, in a “pullover” type exercise, the lifter lies on their back and weights are moved from abdomen to above their head, the weights move both vertically and horizontally, as opposed to a “bench press” where the weights move vertically. The vertical supports 18 are moveable to ensure that the support is above the barbell 16 during the exercise. In further embodiments the supports 18 are fully moveable in the x-y axis thus ensuring that the supports 18 are above the barbell 16 for all range of motions.

Claims

1-40. (canceled)

41. A weight training assistance apparatus which requires a user to overcome the force exerted by one or more weights comprising:

one or more sensors for monitoring a user's activity by monitoring the position of an item indicative of the position of the weights during a weight training exercise;

a processor in communication with said sensors;

the processor enabled to dynamically compare the user's activity of the item during the exercise with a predetermined activity profile to determine a dynamic level of fatigue for the user;

the processor further enabled to determine a response at a given moment based on the exercise undertaken, the current user activity and the determined dynamic level of fatigue;

a load bearing device that is controllable by the processor, the load bearing device enabled to dynamically vary the magnitude of the net force exerted by the weight as determined by the response, the processor further enabled to maintain the magnitude of the force when the user's activity is within a predetermined limit of the predetermined activity profile.

42. The apparatus of claim 41, wherein the item indicative of the position of the weights are the weights used during the exercise.

43. The apparatus of claim 41, wherein the dynamic comparison to determine user activity is a comparison of the position of the item.

44. The apparatus of claim 41, wherein the processor is further enabled to determine a level of muscle fatigue based on the dynamic comparison of user activity and the predetermined profile and determines the response based on user activity, fatigue and failure.

45. The apparatus of claim 41, wherein the predetermined activity profile is a user specific profile for the weight training activity undertaken by the user.

46. The apparatus of claim 41, wherein the comparison is substantially a real-time comparison, and the determination of the response is in substantially real-time.

47. The apparatus of claim 41, wherein the response to fatigue is one or more of the following:

the load bearing device varying the magnitude of the net force exerted by the weight to zero;

the load bearing device varying the magnitude of the net force exerted by the weight wherein the net force exerted by the weight is reduced by an amount proportional to the level of fatigue detected.

48. The apparatus of claim 41, wherein where the load-bearing device is a motor, and where the apparatus further comprises a braking mechanism coupled to the cable and wherein the processor is enabled to control one or more of the speed, torque and braking of the motor.

49. The apparatus of claim 41, wherein the processor is further enabled to compare of the user activity against one or more profiles, which form a pattern profile library to determine if the user activity is indicative of a particular pattern profile wherein the pattern profile library contains known incorrect lifting profiles thereby allowing the identification of incorrectly performed lifts.

50. The apparatus of claim 41, wherein the one or more sensors are contactless sensors selected form the group of: infra-red, ultrasonic or laser based sensors.

51. The apparatus of claim 41, wherein the level of assistance provided by said load bearing device varies according to a measure of the divergence between the predetermined activity profile and the actual user activity.

52. The apparatus of claim 41, where the decision to engage the load bearing device is based on a comparison of the relative position, velocity or acceleration of the weight compared to an expected position based on a pre-determined model.

53. The apparatus of claim 41, further comprising a form of writeable memory and where data regarding previous exercises performed on the apparatus is stored on the writeable memory and wherein the model is based on historic data of previous instances of the same or similar exercise, preferably by the same user.

54. The apparatus of claim 41, wherein the processor is enabled to compare one of more of the following of a user's activity against the predetermined activity profile:

full extension of the user during the exercise;

time between repetitions;

velocity of the weights.

55. The apparatus of claim 41, wherein the processor is enabled to determine if the user has reached failure, where the comparison of the user's activity and predetermined profile is beyond a predetermined limit and further comprising a safety mechanism to bear the entire load wherein the safety mechanism is enabled by the processor in response to high level of fatigue or failure as determined by the processor.

56. The apparatus of claim 41, wherein the apparatus further comprises one or more additional motors, said motors selectively engaged to provide different levels of lift to reduce the net force exerted.

57. A method of self-spotting weightlifting the method which requires to overcome the force exerted by one or more weights comprising;

attaching a load bearing means to one or more weights;

exercising with the weights attached to the load bearing means;

monitoring the position of an item indicative of the position of the weights through one or more sensors;

determining if a user requires help by comparing the position of the item to a pre-determined model;

selectively engaging the load bearing means to dynamically vary the magnitude of the force exerted by the weights in response to the determining step until such time that the user is determined to no longer require assistance; and

maintaining the magnitude of the net force exerted once the user is determined not to require further assistance.

58. The method of claim 57, further comprising the step of:

determining a parameter associated with the item;

determining if the parameter was within a predetermined limit of the predetermined model, and in the event that the parameter is outside of the selectively engaging the load bearing means.

59. The method of claim 58, wherein the parameter associated with the item is one of: position, velocity, acceleration.

60. The method of claim 57, wherein the method further comprises storing information regarding completed exercises to a form of writeable memory.