Is there a sex difference in the bilateral deficit?

Abstract: The bilateral deficit can be described as when the sum of two unilateral movements exceeds the bilateral output. If the sum does not exceed the bilateral output, a bilateral facilitation is present. Little research has been done in males and females comparison of the bilateral deficit. The purpose of the current study was therefore to compare the bilateral deficit between sexes in a 1 repetition maximum (RM) leg press. Twenty participants, ten males and ten females, were recruited (23.4±2.1 years, 71.2±13.1 kg, 172.2±8.9 cm) and seventeen of them completed the study. The test consisted of two testing sessions (one unilateral with preferred leg, and one bilateral session) with seven days in between. The 1 RM was attained within six attempts, with a three minutes rest between every attempt. The current study showed a bilateral deficit of males (5.6±4.6%) and a bilateral facilitation of females (0.6±5.9%). There was a significant difference between sexes of p=0.031 (p<0.05). Previous studies have examined males and females separately, with different methods and protocols. This study used the same method and protocol in both sexes. Some suggestions of the mechanisms behind the deficit have been proposed and may explain the current findings, but further studies are needed. Future research needs to continue to explore and explain the sex difference in the bilateral strength deficit.