Reliability Of Acceleration Assessment Using A Linear Position Transducer During Segmental Thirds Of The Squat

Yousuf Abu-Amara1, Jennifer Rivera1, Ryan W Gant1, Emily C Tagesen1, Anthony G Pinzone1, Edward Z Pelka1, Modesto A Lebron2, Adam R Jajtner1 1Kent State University, Kent, OH2University of Central Florida, Orlando, FL PURPOSE: To assess inter-set and session reliability of a linear position transducer (LT) at four intensities of the back squat (BS) across three segments. METHODS: 17 individuals at least six months resistance trained. (24 ± 4 yrs, 1.71 ± 0.07 m, 80.8 ± 11.2 kg) completed the study. Participants completed three visits separated by at least 48 hours. During Visit 1, participants provided written informed consent and completed a one-repetition maximum (1RM) of the BS. Visit 2 and 3 consisted of two sets of three reps at 30, 50, 60, and 70% 1RM with three minutes rest between sets. The LT was placed on the medial side of the barbell sleeve with the retractable belt perpendicular to the floor. Position was measured at 100 Hz with velocity determined as change in position over time and filtered with a 0.10s rolling average. Repetitions were identified by a displacement of 15 cm with repetitions starting at a filtered velocity of 0.05 m•s-1. The concentric movement was segmented into equal thirds at bottom (BOT), middle, (MID), and top (TOP). Average acceleration (ACC), defined as change in velocity over time, was then determined in each segment. ACC was assessed as the average of three reps in each set (AR) or taken as the rep with the highest mean velocity over the full movement (BR). Inter-set and session reliability was assessed with Interclass Class Correlations (ICC) and paired samples t-tests. RESULTS: Good to excellent ICCs were noted in inter-set ACC at 30, 50 and 60%1RM for all segments, poor reliability was observed at 70%. Moderate to excellent ICCs were observed for inter-session ACC at 30%, 50% and 60% for all segments, poor ICCs were observed at 70%. Inter-set differences were observed for 30% TOP and 60% MID, while inter-session differences were observed for 60% MID. CONCLUSION: The LT can reliably assess ACC at intensities up to approximately 60% 1RM both between sets and sessions. ICC = Intraclass Correlation Coefficient; MD = Minimal Difference; * Significance difference Character count: 1689