Integral Kinesiology Feedback for Weight and Resistance Training Steve Mann, Cayden Pierce, Bei Cong Zheng, Jesse Hernandez, Claire Scavuzzo, Christina Mann MannLab, 330 Dundas Street West, Toronto, Ontario, M5T 1G5, Canada Abstract—Existing physical fitness systems are often based on kinesiology. Recently Integral Kinesiology has been proposed, which is the integral kinematics of body movement. In this paper, we apply integral kinesiology to the bench press, commonly used in weight and resistance training. We show that an integral kinesiology feedback system decreases error and increases time n Absement or distance,x Absity Dispacement or speed Velocity spent lifting in the user. We also developed proofs of concept in (d/dt) x, Acceleration aerobic training, to create a social physical activity experience. for n=... -2 -1 0 1 2 ... We propose that sharing real time integral kinematic measures Kinematics between users enhances the integrity and maintenance of resis- tance or aerobic training. Integral Kinematics Fig. 1. Kinematics ordinarily involves the study of distance or displacement, I. INTRODUCTION dn x, and its derivatives, dt x; 8n ≥ 0. This gives us only half the picture. We This paper presents the application of integral kinesiology wish to also consider negative n, i.e. integrals (integral kinesiology), such as R x(t)dt = (d=dt)−1x(t) to weight training, resistance training, and the like. absement . The word “kinesiology” derives from the Greek words feedback[6], [7], and thus optimize exercise even without the “κινηση” (“kinisi”), meaning “movement”, and “logoc” (“lo- use of the system[8]. We have also proposed pro-social uses gos”), meaning “reason”, “explanation”, or “discourse” (i.e. of this tool pertaining to sharing feedback amongst users “study”). to facilitate initiation and maintenance of physical activity. Kinesiology, is movement science, closely connected with Therefore, our tools could greatly add to the amplification and kinematics. Kinematics, is the study of the mechanics of maintenance of regular physical activity providing closed loop the motion of objects without considering the forces acting feedback in addition to social support (as suggested in [9], [8]) on the objects, i.e. typically the pure study of distance (or displacement) and its time-derivatives, speed (or velocity), A. Background acceleration, jerk, jounce, etc. Taking the derivative of a quantity is akin to acting on it Integral kinematics [1], [2], [3] is kinematics in which with a differential operator, i.e. (d=dt)n, where n gives us the we also consider the time-integrals of position, such as, nth derivative. For velocity we have n = 1, for acceleration, absement [1], [4] (the first time-integral of position). n = 2, for jerk, n = 3, for jounce, n = 4, and so on.... Integral kinesiology is movement science that includes But this is only half the picture, i.e. we should also consider position and its derivatives as well as its integrals. Integral negative values of n for the complete picture. kinesiology includes measuring the absement (time-integral When n = −1, the result is a measurement known as of distance or time-integral of displacement) during exercise. absement. Absement is the time integral of displacement or We proffer as state-variables of a phase space, momentement distance, and thus can be used to measure total deviance (error) (time-integral of momentum) and absement, upon which we from a baseline value that we wish to maintain. In weight may apply machine learning. The first machine learning algo- training, one baseline we wish to maintain is the pitch of rithm to be applied to phase space was LEM, also known as the barbell, which needs to stay level with the floor. Another the adaptive chirplet transform[5]. dimension we want to maintain for proper lifting is the yaw, The word “integral” derives from the same Latin language to keep the barbell steady from wrist rotations. In the current root as the word “integrity”, and “integer”, meaning “whole- study, we offered only one form of feedback on the absement ness” or “completeness”, and this is apt, as integral kinesiology of pitch, while also simultaneously measuring the ongoing pertains to a certain kind of integrity through completeness absement in the yaw. Therefore, the measurement of error that (i.e. including not just derivatives of position, but also integrals is of interest in the current study is the pitch absement. See of position). Fig. 1 We assume small deviation, so that sin θ ≈ θ for small The goal of this work is to develop a closed loop feedback θ, so absement can be approximated by anglement. system to improve the integrity of exercise training. Im- provement of integrity means improvement in exercise form. B. Related Work Additionally, a system can helpfully alter behaviour in the Exercise has traditionally used metrics like distance, speed, long term, so that the user can adapt their behaviour to the and acceleration (for example see[10], [11]). Now, with in- tegral kinesiology, absement is a vital metric to consider trainers is limited, and an observer (no matter their training) when assessing the integrity of a lift during weight train- simply cannot provide the speed and accuracy of instruction ing. There are many existing ways to track motion, see, that a real-time electronic closed-loop feedback system can. for example[8][12], [13]. We track motion and provide real- Thus, integrated kinesiology applied to bench press can fill time feedback to users, such that they can correct their a major need, providing easier access to precise real-time behaviors, as suggested in[7], in much the same way that feedback. Feedback helps individuals performing exercise[18]. bio-feedback has been previously used for rehabilitation[14]. In addition, the application presented here will also store Integral kinesiology can help with form during weight training, absement over time, across repetitions, sets, and workouts, by providing feedback to the lifter about their absement, as providing opportunities for long term review and assessment. deviation from maintaining proper form. As the absement in The bench press (see Fig.2) is one of the most common prescribed movement grows, the user can be provided a cue weight training techniques. It is a compound workout that that creates an incentive toward proper form (or a disincentive primarily works the triceps brachii, pectoralis major, and the away from bad form). This cue takes the form of an indicator anterior deltoid. During a bench press, lifters often experience that directly represents the current error. bad form (error) on multiple axes. One of the most common In past works, integral kinesiology has been applied to the errors that occurs is an asymmetry in arm extension whilst training of core muscles using fitness games[2]. The MannFit performing the lift, causing an increase in absement in the mobile app[3] was previously developed to give feedback pitch [18] . This results in the barbell becoming unparalleled about absement to motivate a subject in a planking task, where with the floor, improper muscles being worked, and the growth of the absement produced audio or visual feedback creation of muscular asymmetries, all of which can result in such as warping of accompanying music, or simulation of injuries. Here, we can define error and infer asymmetry in spilled water[2]. Users of the MannFit app experienced greatly muscle recruitment by assessment of how parallel the barbell decreased absement during planking, suggesting a more stable is with the floor. Therefore, when users have a tilt in the bar, plank form. Also, training with this feedback system allowed the system records the absement of the tilt and simultaneously for the development of longer, sustained, low-absement plank- provides real time visual feedback for the user to correct the tilt ing sessions. We focused on monitoring absement during of the bar during the lift. By storing absement across workouts, barbell bench presses, to measure the error of the user whilst the user is able to track these asymmetries over time. also updating the user on their error through real time visual feedback built into the bench press rack (see Fig.2). The time III. HYPOTHESIS integral of distance is the total error in deviation from zero We hypothesize that providing a participant using a bench (straight), in position, during weight training. We use absement press with an absement-based feedback system of pitch (i.e. as a measure of error across various axes. Here, the tilt of feedback based on the tilt of the bar), there will be an the bar (the pitch, see Fig. 3) during lifting is measured and improvement in their overall form. A closed-loop feedback relayed back to the user with visual feedback in real time. system, where the participant is a part of the loop, will result in Overall, the system presented here is an application of the lower absement and therefore better form. In addition, we take principles used in the previous MannFit mobile app[2]. The simultaneous measures of absement in the yaw (rotation of the mobile portion of the new system presented here (Fig. 4, 5, 6) barbell), while not offering feedback for it. We hypothesize is implemented as an extension to the already existent MannFit that having feedback about the pitch will reduce the absement application[2]. in pitch, but will be unlikely to improve (reduce) absement in yaw. II. INTEGRAL KINESIOLOGY RATIONALE IN WEIGHT TRAINING IV. EXPERIMENTAL SETUP Integral kinesiology involves a combination of strength and The experimental setup consists of five main components: dexterity, and puts emphasis on simultaneously maintaining an iron barbell, an MPU-6050 inertial measurement unit, a and training strength and fine motor control. During weight Sequential Wave Imprinting Machine (S.W.I.M.)[19] (imple- training, individuals must engage in proper lifting form to mented using a Teensy 3.2 microcontroller and an Adafruit avoid injuries, ensure the proper muscles are worked, and DotStar APA102 SMD LEDs), an Espressif ESP32 microcon- maintain muscular symmetry of the body [15], [16].