european college of sport science

Friday, June 26th, 2009
condition was compared with the same movement while holding hand grips hanging from to slings attached to the ceiling (Unstable
condition). Body angle and hand width were identical under both conditions. The slings were equipped with force transducers and unilateral
peak force production was summed. Movement was initiated from an outstretched position, lowering to 90 degrees elbow flexion
and explosive extension. Subjects performed 3 series of 3 maximal efforts for each test, on two separate days separated by 48 hours or
more. Pearson r were used to investigate test-retest correlation, Paired Samples T-test were used to evaluate potential learning effects,
while Coefficient of Variation was used to estimate typical variation. The results from test day 2 were used to quantify the impact of instability
on maximal force.
Results: Test-retest comparisons showed no systematic bias for either condition from day 1 to day 2. Test results were highly correlated (r=
0.94 and 0.90 for stable and unstable conditions respectively). Coefficient of variation was 8% for the stable test and 5% for the unstable
test. Unstable conditions resulted in a 30% reduction in peak force compared to stable conditions (1061 ± 414 vs. 743 ± 148 N, p