Evaluation method of a sports performance

This invention relates to a evaluation method of a sports performance and to a device for evaluating a maximum result in sports performances associated in lifting weights, for example bench press.

Best known way of evaluating a maximal bench press result of a person is to perform the bench press movement by adding weights to a bar gradually. Maximum result is the result, that the person can yet lift. Further, another known way of evaluating a maximal bench press result of a person is to examine, how many repetitions a person can do by using weights clearly smaller than the assumed maximum, and to evaluate the possible maximum from this number of repetitions, based on experience. Further, a specific device for measuring the muscle strength with a measuring arrangement included in the device, is disclosed in patent publication DE 19733595.

The problem related to these known solutions is risk of injury, when using maximum weights in empirical determination of the maximum result, since using big weights has always its own risks, e.g. risk of muscle ruptures, additionally for instance with competing athletes making maximum performances requires both mental and physical resources before competition and thus the maximum result should not be evaluated this way close to the competition moment. Further, in evaluating the maximum, the valuation accuracy of maximum is poor, when using the number of repetitions achieved by using clearly smaller weights than the maximum weight, since the evaluation is typically based solely on experience and the dependence relation, that functions for one person, does not necessarily func- tion for another person. In addition, also this definition method of maximum is heavy, because it requires the experimenter to perform as many repetitions he can to fatigue. Further, with the method described in patent publication DE 19733595, the maximum strength can only be evaluated by using the large device in question, not by using for instance an official weightlifting bar.

A device attached to wrist is known from application EP1366712, which device includes a motion sensor, keyboard and display. The device is used for measuring and evaluating the movements of the user, from which movements variables are calculated, which variables are shown on the display of the device. The device can e.g. be used for concluding, if the person carrying the device is walking or running. Energy comsumption during motion can also be calculated from the information.

Application publication US 2004186378 describes a pulsemeter to be attached to wrist, which pulsemeter can remove the noise signals distorting the pulse measurement, which noise signals are caused by the movement of the person.

The object of the invention is to solve the problems associated with the evaluation of maximum of bench press or other corresponding lifting motion and to achieve a multipurpose evaluation method of sports performance as well as a device, with which the maximal weight lifting results of a person can be evaluated, by using weights clearly smaller than maximum. The invention reduces the risk for injury in testing the maximum of bench press and additionally increases the precision of evaluation, when compared to a method based on analysing the number of repetitions achieved with smaller weights, due to the especially accurate measurement method. Further, the device is to be suited for use with the conventional weightlifting bars, loose weights or devices, that the devotee in the sport tends to use, and not be limited to e.g. a large special device allowing only specific movements and equipped with measurement sensors, as in the case of reference publication DE 19733595.

The object is achieved with the invention, that is a wrist watch-like bracelet, including a sensitive acceleration sensor and keyboard for feeding the information, as well as a display for presenting the evaluated maximum result. The invention can be used for evaluating the maximum result e.g. in bench press, by using two different weights clearly smaller than the maximum, as follows: the user enters the weight of the first weight in the bar in kilograms with the keyboard into the bracelet and performs the lifting motion such, that the bar lifting phase is done as fast as possible. Then the other weight is placed into the bar, the weight of which weight is entered in kilograms into the bracelet and the lifting motion is performed again as in connection with the first weight. The bracelet saves the maximum accelerations during both lifting motions in lifting plase of the bar. The bracelet examines the differences in maximum accelerations during both lifts with a special algorithm and evaluates the maximal weight lifting result of the experimenter in kilograms, by using the maximum accelerations and kilogram amounts of weights used in the lifts and finally shows the result on the display of the bracelet. The bracelet can be used in several lifting motions, e.g. biceps curl or squat, in addition to bench press.

More exactly, the measurement method for sports performance according to the invention is characterised with what is described in connection with the characterizing part of the independent claims.

Next the invention is described in further detail referring to the accompanying drawings, wherein:

figure 1 illustrates the use of the invention in bench press,

figure 2 illustrates the operating principle of the device according to the invention,

figure 3 illustrates the signal measured by the sensor of the invention in an example case, and

figure 4 illustrates the operating principle of the maximum result evaluation method.

Next the invention is described with help of some exemplary embodiments.

The invention is a bracelet 1 , that is used in the example case illustrated in figure 1 to determine, how much weight a person can lift at maximum in bench press. As the person lifts the bar 2 and the weights 3 attached into it, the bracelet 1 moves to the same direction as the bar 2. The bracelet 1 consists more accurately of parts, that are illustrated as a diagram in figure 2. The bracelet consists of an acceleration sensor 4, a keyboard 7, a memory 5, a processor 8 and a display 6.

In an example case, in which it is assumed, that the bench press maximum of the person is well over hundred kilos, the invention functions as follows:

The person sets into the bar such a weight, that he can certainly lift, for instance 40 kilograms and enters this information into the bracelet with keyboard 7. The processor 8 of the bracelet saves the kilogram amount into the memory 5 of the device and starts recording the signal of the acceleration sensor 4. Next the person lifts the weight up as fast as he can. During the lift the processor 8 saves the signal of the acceleration sensor 4 to memory 5.

Next the person sets a second weight, bigger than the first weight, into the bar, for instance 70 kilograms and again enters the information into the memory 5 of the device with keyboard 7 and performs a new lifting motion by lifting the weight up as fast as he can. As with the first lift, the signal of the acceleration sensor 4 is saved to memory 5 of the bracelet.

The acceleration sensor signal during the two performed lifts is illustrated in figure 3, wherein two lifts are shown, the first lift 9 and the second lift 10. In the first lift 9

the largest acceleration has been A1 m/φ and in the second lift 10 the largest acceleration has been A2 m/s?.

Next the processor 8 of the bracelet 1 starts to evaluate the maximum value of the bench press of the person, based on the information in the memory 5, by using the principle described in figure 4. Figure 4 includes a curve, horizontal axis of which depicts the lifted weight in kilograms and the vertical axis depicts the maximum acceleration of the lift in units m/s?. Processor 8 performs a calculation, in which it first places the point of the first lift 9 into the coordinate system according to figure 4 to location (P1 , A1) wherein P1 is the weight used in this lift and A1 is the maximum acceleration of this lift and the point of the second lift 10 to location (P2, A2) wherein P2 is the weight used in this lift and A2 is the maximum acceleration of this lift. Then the processor 8 defines a line 11 , that travels through these points and examines, where this line reaches the value zero on the vertical axis and defines the reading P _ma χ corresponding this point, which reading presents the esti- mated maximal result in the lifting motion in question and shows this result on the display 6.

This calculation is based on the idea, that when lifting the bar with a small weight, the maximum acceleration is large, but in the situation, where the lifting acceleration of the bar is zero, the person can no longer lift the bar, which means, that the weight is bigger than the person can lift. Thus the biggest weight the person can lift is roughly the point on the horizontal axis of figure 4, in which point the line 11 for the first time reaches the value zero.

Within the scope of the invention even solutions deviating from the aforedescribed can be considered. For instance the number of performed lifts can be more than two, when for instance three lifts can be used in calculating the maximum value Pm _a x- Then adaption of a second order curve can be used in calculating the maximun value P _max .

The maximum value P _ma χ can be estimated roughly also based merely on one measurement, by using a default value of the slope of line 11. Then the maximum value P _max can be estimated roughly based on only one measurement.

In addition, the maximum value P _ma χ can be estimated from maximum accelerations and used weights, by using other than a linear line: the line 11 can be replaced for instance with a y=1/x -type curve or some other curve, that is fitted into the group of points formed of the maximum accelerations and used weights.

Further, a special algorithm can also be used in calculating the maximum performance, which algorithm uses, besides the signals of acceleration sensors, information of e.g. the height of the lifter, weight of the lifter and the age of the lifter e.g. such, that the algorithm observes also, that heavy persons typically have a large muscle mass, when probably the value of the actual maximum performance is a few kilograms greater than the value of lighter persons, even if the P _max -value calculated from the signals of acceleration sensors was the same for both persons.

Some preferred embodiments of the method and device according to the invention are described above. The invention is not however limited to the previously described embodiments. The inventional idea can be applied in several ways within the limits of the claims.