Exercising and measuring apparatus
The present invention relates to an exercising and measuring apparatus for exercising body muscles and for measur ing muscular functions.
A greater force can be developed when extending skeletal muscle, so-cal led negative work, than when contracting such muscle, so-cal led positive work. In addition, the slower the muscle contraction rate, the greater the force developed during positive work.
Conventional physical exercise apparatus and devices, such as dumbbel ls , bar-weights, weight-l ifting machines and l ike muscle exercising devices have a l i itive eff¬ ect on muscle t ra i n i ng , . s i nee they are unable to develop maximum force during the whole of" the movement (s) per- for. ed thereon, because the load is a function of the exercise weight used and its position in relation to the hi nge or joint about which it moves . Training or exer¬ cise of the arm muscles with the aid of dumbbel ls can be taken as an example. Assume that a person stands wi th one arm extending straight down whi le grasping a dumb¬ bel l in the hand of that arm. Assume now that whi le holding the upper arm stationary, the lower arm is swung from its vertical downwardly di rected position to a sub¬ stantial ly upwardly di rected vertical position, i .e. with the hand facing upwards. When, during this movement, the lower arm reaches a horizontal posi tion the load on the muscle in the upper arm is at a maximum, since the torque prevai l ing around the el bow is also at a maximum. The load on the muscle then decreases successively as upward movement of the lower arm is continued, and is substantial ly zero when the lower arm reaches an upward
vertical position with the hand uppermost. The same circumstances apply when the lower arm is lowered slowly to its original downwardly extended vertical position.
Correspondingly, leg muscle exercises also fail to exert a maximum load on the muscles.
An example in this regard is found in the leg exercise in which a person is required to be seated with his/her thighs extending horizontally and the lower legs, or calves, extending vertically. A weight is normally applied to one foot or to both feet, depending on the nature of the exercise, and the lower leg is lifted to a horizontal position. In the case of this particular leg movement the leg muscles are able to generate max¬ imum torque around the knee joint at a so-called leg angle of 60 . The torque which can be generated at the moment of raising the lower leg from its vertical pos¬ ition is relatively very low however. This means that in order to be able to begin to move the leg', the weight hanging from the foot must be relatively low, which in turn means that the muscles need not develop maximum force when the leg has been straightened slightly.
These circumstances also apply in the case of other muscle exercises.
Consequently, the muscles are not loaded to the full throughout the whole exercise when training on conven¬ tional exercise apparatus or devices. In order to ob¬ tain optimum training stimulus it is most important that the muscles are subjected to the same degree of relative tension throughout the whole movement, i.e. can be plac- ed under maximum load in each part of the exercise.
It is also important, in respect of obtaining optimum training stimulus, that the muscles can be placed under
maximum load both when carrying out the physical exer- cise slowly and when it is carried out quickly.
The present invention relates to a physical exercise apparatus which enables the muscles to be placed under maximum load or tension throughout the whole movement of the exercise and which enables selection of the speed at which thi s movement is performed. The apparatus according to the invention also enables the force gener¬ ated by a muscle to be measured during the whole of this movement .
Thus , the present invention relates to an exercising and measuring apparatus bei ng charac erized by a lever against which a person is Intended to exert a force, the lever being mounted for rotation on an axle which is connected to a motor; and is further charac erized in that the lever i s also connect.ed to a force transducer or sensor which measures the force exerted on said lever; in that a motor control means is provided for control l ing the speed of the motor, and therewith the rotational speed of the lever on i ts axle, so as to maintai n a p re-d ete r i ned value set by means of a value-setting device; and that the control means is arranged to control the motor so that said motor i s driven when the force exerted on the lever corresponds to a smal lest p re-d eterm I ned force set by said setting means .
The i nvention wi l l now be described in more detai l with reference to an exempl i fying embodiment thereof i l lus- r-a ed in the accompanyi ng drawi ng, in which
Figure 1 i s a perspective view of an apparatus according to the invention ; and
Figure 2 is a block schematic of an electrical circuit.
Thus, the physical exercise and measuring apparatus en¬ ables the exercising person in question to tension or load his/her muscles to a maximum throughout the whole movement, since the arm or the leg is bent or stretched at a speed determined by the motor. Thus, the motor actually retards a given movement and hence the muscle exercised is afforded the opportunity of developing maximum tension for each pivot angle of an arm or a leg during both positive and negative work. The rate at which the particular muscle contracts can also be varied by varying the motor speed in accordance with the pur¬ pose of the exercise.
Figure 1 illustrates an embodiment of the apparatus acc- ording to the invention. The apparatus includes a lever
I having attached thereto at one free end thereof an assault device 2 against"which the person performing the exercise is intended to exert a force through his/her arms or legs. The lever 1 is journalled to a housing 3. The journal mounting connecting the lever 1 to the hous¬ ing 3 is firmly connected to a bench 4 or the like on which the person is intended to sit or lie when exerting a force on the assault device 2 through the arms or the legs. The assault device is preferably padded with soft pads 5;- 6 or the like.
The housing 3, the bench 4 and an associated back-rest 7 are suitably attached to a frame structure 8.
The lever 1 is pivotably connected to an axle 9, which is coupled to an electric motor 10 in the housing 3. Connected to the lever 1 is a force sensor or transducer
I I which is intended to register and measure the force exerted crj'-the lever 1. The force transducer 11 may be
located at the point of attachment of the assault device 2 with the lever 1 for direct measurement of the force exerted on the lever, or may be connected to the axle 9 for measuring the torque generated by said force, the torque being converted to a force applied to the assault device with the aid of some suitable -electronic circuit, using herefor knowledge of the distance between the ass¬ ault device 2 and the axle 9.
The force transducer may be of any suitable kind and is thus constructed to produce an electric signal corres¬ ponding to the force exerted on the assault device, and to transmit this signal to a control unit via an ampli¬ fier 27. The control unit includes a control circuit 12 and a motor-control means 14. The circuit 12 incor- porates a comparator 13. The motor-control means is connected to a voltage source.
The signal from the force -transducer 11 is transmitted to the control circuit 12. Connected to the control circuit 12 and to the comparator 13 is a setting device 15, which includes a button bank 16 and preferably one or two displays 17, 18. The aforesaid force can be set to a given value through the button bank. In addition, the button bank can be used to set a value relating to the rotational speed of the lever, i.e. the speed of the motor. -Suitably, there is used one display 17 for dis¬ playing the value of the force and one display 18 for displaying the set value of the rotational speed of the lever 1. The setting device 15 may also include a microcomputer or other suitable, known electronic cir- cuits for converting force and rotational-speed values entered through the button bank to respective electrical signals for subsequent transmission to the control cir¬ cuit.
A comparison is made in the comparator 13 between the value of the force present through the setting device15 and the electric signal produced by the force transducer 2.
When the force exerted on the assault device 2 exceeds the preset force, the control circuit 12 sends to the motor-control device 14 a signal which corresponds to the rotational speed of the lever 1 preset through the setting device. The motor-control device:';14 then steers the motor, via transmission means not shown, so that the lever is rotated at the preset speed; the motor-control device 14 may be of any suitable kind, such as a thyris- tor control for example.
The motor is stopped when the force acting in the assault device falls beneath the aforesaid preset force.
Should the force exerted on the lever exceed the preset value, the arm will still not be rotated, at a speed greater than that corresponding to the preset value, despite this greater force. The lever 1 moves from the position illustrated in Figure 2 in the direction of arrow 19, which corresponds to the arrow 20 in Figure 1, until it activates a limit switch 23. When activated the limit switch sends a signal to the control circuit 12, which stops the motor 10 in response thereto. The lever 1 can then be caused to return to its starting position, in response to instructions given by the set¬ ting device 15, whereafter further "rotational movement 19 can commence when sufficient force is applied to the assault device 2.
Alternatively, the setting device 15 can be programmed to instruct the motor 10 to drive the lever in the dir¬ ection of arrow 21 (22) when the force applied to the
assault device 2 exceeds the preset force.
For example the preset force may be from 1N - 250N, al¬ though this range can be altered to accord with partic¬ ular applications. For example,- a force of 5N has been found to be a suitable initial force.
The lever may be arranged to rotate through an angular range of from 90 to 180 , preferably through an angle of about 120 . The speed of rotation may be such as to enable a complete movement to be performed in a time period of e..g., 1 - 30 seconds. The aforegiven values should be taken solely as examples.
It will be clearly seen from this that the aforesaid advantages are- obtained by means of the present inven¬ tion.
According to. a preferred embodiment the control means 12 includes an input which Is intended to receive an electric signal transmitted by a position-transducer or sensor connect¬ ed to the lever axle 9, this position-transducer prefer¬ ably being a conventional angle-transducer or sensor 24.
According to a further preferred embodiment the control means includes an output 25 which is constructed to pro¬ duce an- electric signal corresponding to the force ex¬ erted on the lever 1 and/or an output 26 which is const¬ ructed to produce an electric signal corresponding to the rotational position of the lever axle 9. The first mentioned signal is generated by the force transducer 11 and the last mentioned signal by the angle transducer 24 The outputs 25, 26 are intended for connection to, e.g a printer, so that the force exerted by the person per- forming the exercise at different pivot or joint angles can be recorded and studied. This is a significant em-
bodiment of the present invention with respect to foll- -owing-up the result of a person's training program and with respect to testing various people during, e.g., a period of rehabilitation. One important factor in the medical rehabilitation of athletes or sportsmen is that it is possible to determine dynamic strength functions at various speeds of movement, both in the case of dy¬ namically positive and negative work.
The present invention thus provides an apparatus with which a person is able to carry out physical exercises and by means, of which it is possible to test the positive and negative maximum muscular force of a person through a full working cycle for an arm, a leg, etc.
It will be appreciated that hip and chest muscles can be exercised and tested in a corresponding manner.
The invention shall not be considered as restricted to the above embodiments, since various modifications can be made within the scope of the following claims.