Abstract: The purpose of this study was to investigate the reproducibility of
findings derived from a new iso-inertial dynamometer during bench press (BP)
and squat (SQ) and to provide descriptive data for recreational athletes. A
position transducer and accelerometer were combined to assess velocity and
power during free weight lifting exercises. Simulated movement with a pulley
system revealed the excellent technical consistency of the dynamometer. Sixteen
male subjects participated in the study. Iso-inertial tests consisted of
lifting as fast as possible four different relative loads (35, 50, 70, 90% 1RM
in BP and 45, 60, 75, 90% 1RM in SQ). The test was repeated one week later.
Analysis of variance revealed no significant variation between sessions or
trials. Reproducibility was better in velocity than in power, although it
remained fairly good in both exercises (coefficients of variation [CV] never
exceeding 10%) except for the time to peak power parameter. Descriptive data
confirmed the classical force-velocity and force-power relationships for BP and
SQ. In conclusion, this study demonstrated reliable measurements in BP and SQ
iso-inertial exercises. Monitoring force-velocity and force-power relationships
offers an original functional approach in strength training supervision.
