Validating Two Systems for Estimating Force and Power

Abstract

This study examined the validity of 2 kinematic systems for estimating force and power during squat jumps. 12 weight-trained males each performed single repetition squat jumps with a 20-kg, 40-kg, 60-kg and 80-kg load on a Kistler portable force plate. A commercial linear position transducer (Gymaware [GYM]) and accelerometer (Myotest® [MYO]) were attached to the bar to assess concentric peak force (PF) and peak power (PP). Across all loads tested, the GYM and MYO estimates of PF and PP were moderately to strongly correlated ( P≤0.05-0.001) with the force plate measurements ( R=0.59-0.87 and R=0.66-0.97), respectively. The mean PF and PP values were not significantly different between the 2 kinematic systems and the force plate, but the estimates did produce some systematic bias and relatively large random errors, especially with the 20-kg load (PF bias >170 N, PF error >335 N, PP bias >400 W, PP error >878 W). Some proportional bias was also identified. In summary, the estimation of PF and PP by a linear position transducer and accelerometer showed moderate to strong relative validity and equivalent absolute validity, but these estimates are limited by the presence of bias and large random errors.

Validity of wireless device measuring velocity of resistance exercises

“…6,11 The criteria for statistical significance was set at p=0.05. Correlation values were interpreted according to scale developed by Hopkins: 0.0-0.1, 0.1-0.3, 0.3-0.5, 0.5-0.7, 0.7-0.9, and 0.9-1.0 were interpreted as trivial, small, moderate, large, very large, and nearly perfect.…”

“…A standard instrument to measure kinematic qualities of movement is three-dimensional (3D) motion capture hardware and software. As in past studies for validation purpose on kinetics and kinematics, different types of devices are being used, 6 but 3D motion capture system was deemed a satisfactory criterion measure to test that the PUSH™ device as it is capable of reporting accurate data with minimal errors. The device is relatively new and its data acquisition accuracy requires examination scientific examination in order to determine its reliability.…”

Évaluation et analyse de la performance par accélérométrie lors des mouvements de musculation

“…Pour mesurer le temps passé immobile ou bien en mouvement tout au long d'une journée dans le but par exemple de définir le degré de sédentarité on utilisera plutôt un accéléromètre avec une fréquence comprise entre 25 et 60 Hz (Bouten et al, 1997 ;Chen et al, 2005 ;Cleland et al, 2013 ;Kavanagh et al, 2008). Pour la mesure des accélérations d'un point sur le corps lors d'un saut ou d'une course ou bien encore d'une barre de musculation on utilisera des fréquences allant de 100 à 1000 Hz (Choukou et al, 2014 ;Crewther et al, 2011 ;Jidovtseff et al, 2006 ;Sato et al, 2009). Plus le mouvement est dynamique et plus la fréquence d'enregistrement devra être élevée si on veut obtenir une image précise du mouvement analysé sans erreur lors des procédures de calcul.…”

“…Plusieurs études récentes ont étudié la validité de l'accélérométrie dans des conditions de mouvement non guidées, plus proches de la réalité de terrain (Bampouras et al, 2013 ;Comstock et al, 2011 ;Crewther et al, 2011 ;McMaster et al, 2013 ;Sato et al, 2009). Les résultats ne semblent pas montrer l'existence d'un biais plus important lorsque le mouvement n'est pas guidé.…”

Estimation of force during vertical jumps using body fixed accelerometers

“…Another study showed a comparison of the accelerometer and force platform measures during jumping and found moderate levels of agreement between devices when measuring vertical peak force [7]. Similarly, vertical forces were examined in squats and found moderate to high correlations between forces from an accelerometer and force platform [8]. By contrast, very good agreement between devices was found in determining flight times 1 in vertical jumps [9].…”