Inter-session Reliability Of A Linear Position Transducer During Four Intensities Of The Barbell Back Squat

PURPOSE: To determine inter-session reliability of a linear position transducer (LT) during four intensities of a one-repetition maximum (1RM) barbell back squat (BBS). METHODS: Eight healthy men and women (Men: N = 5; 24 ± 5 yrs; 79.6 ± 11.6 kg; 171.1 ± 5.0 cm) with at least six months of prior resistance training experience and an ability to safely perform the BBS were recruited for this investigation. Participants reported to the laboratory for three visits separated by at least 48 hours. Visit one consisted of providing written informed consent and completing a 1RM of the BBS. Visits two and three consisted of two sets of three repetitions at 30, 50, 60, and 70% 1RM with at least three minutes of rest between sets. The LT was placed on the medial side of the barbell sleeve, with the retractable belt perpendicular to the ground. Position was measured at a frequency of 100 Hz with raw data filtered using a 0.10s rolling average while each repetition began once filtered velocity exceeded 0.15 m•s-1. The set with the highest mean velocity (MV), defined as the average over three repetitions and best repetition were compared in bar displacement (D), MV and peak velocity (PV). Reliability was determined using a two-tailed dependent sampled t-test and Intraclass Correlation Coefficients (ICC). RESULTS: Data are presented in Table 1. Most measures revealed strong reliability with no differences between sessions. However, differences between days were found in average MV and PV at 30%, average D at 60%, best MV and PV at 30%. Moderate reliability with no difference between sessions was found in best D 60%. CONCLUSION: The LT exhibits strong inter-session reliability for average and best MV, PV, and D. Differences observed between days at 30% MV and PV, and the moderate reliability in best 60% D, may have been influenced by the variable training status of our participants. Future research should consider participant training status when examining inter-session reliability of the LT.