Detecting repetitions and time features in resistance training using triaxial accelerometry

Abstract

Accurately determining resistance-training parameters is crucial to gain knowledge about the training process and to evaluate training interventions. To current knowledge, no method exists to automatically detect a series of features in a repetition training session using one three-dimensional accelerometer. In this study, a specific algorithm was used to detect the number of repetitions and different time features. Features determined by the acceleration algorithm were compared to a reference system using a linear wire encoder to detect movements. A total of 50 healthy participants were randomly assigned to three different groups (maximal strength, hypertrophy, and muscular endurance) and executed three different resistance-training exercises (bench press, leg press, and trunk flexion). Results of both measurement systems were compared for agreement using Bland -Altman plots, regarding repetition numbers, TUT (time under tension) in concentric, eccentric, and isometric contraction forms and total TUT (sum of all contraction forms) as well as break between repetitions. Both methods showed high agreement in repetition count (mean error 20.2^0.6 repetitions). Time features were detected with less agreement, with 10.0% disagreement for TUT in first phase, 1.1% disagreement for second phase, and 56% disagreement in isometric contraction. However, it was possible to detect a series of time-based movement features, enhancing the possibility to objectively record different parameters of a resistance training session. This will improve research in resistance training and also bring advantages in the training process for coach and athlete.

Trends Supporting the In-Field Use of Wearable Inertial Sensors for Sport Performance Evaluation: A Systematic Review

“…Screening of the selected papers and the 23 reviews produced 77 additional papers. As a result, 286 studies were identified for inclusion in the systematic review [ 24 , 41 , 43 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , ...…”

“…Both types of assessment have been performed using MIMUs that provide instantaneous acceleration (and therefore force) data along with an integrated measurement of velocity to determine muscular power: explosive performance was assessed for the lower limbs during jumps [ 13 , 83 , 84 , 92 , 93 , 97 , 100 , 117 , 150 , 166 , 167 , 199 , 213 , 218 , 219 , 220 , 233 , 244 , 251 , 257 , 258 , 281 , 286 ] and for the upper limbs [ 78 , 141 , 151 , 190 , 236 , 310 ]. Force and power production capacity were quantified during maximum dynamic strength tests for the upper limbs [ 76 , 97 , 103 , 172 , 186 , 198 , 252 , 261 , 305 ] and lower limbs [ 64 , 65 , 76 , 82 , 97 , 172 , 252 , 265 , 289 ]. As an indirect assessment of force production capacity, static muscular stiffness ha...…”

“…The reliability and accuracy of velocity and power measures performed using accelerometers during maximum dynamic strength assessments were evaluated, often in comparison with other assessment methods for upper limb muscular power [ 97 , 305 ] and during squat lifts [ 64 , 97 , 150 , 289 ]. Reliability and reproducibility were also assessed for repetition and time under tension during leg and bench press exercises [ 76 ]. The reproducibility of velocity and power estimates during squat lifts [ 82 , 172 , 289 ] and bench press exercises [ 172 ] have been assessed.…”

Analysis of Time Under Tension in Bench Press Exercise in Recreationally Trained Individuals: A Systematic Review

“…The use of different cadences can affect the TUT and affect the training volume and intensity (15). The capacity to lift external load reduces from the increase of the TUT (1).…”