The bilateral deficit phenomenon (BLD) is a reduction in performance during a bilateral
motor task when compared to the performance during the unilateral version of the same motor
task. The objective of the current study was to determine if there was a BLD during maximal arm
cycling Wingate tests. Thirteen healthy male participants performed three 30-second maximal
arm cycling Wingate tests during three experimental sessions. Each session the participants
completed Wingate tests with 1) both arms, 2) dominant arm, and 3) non-dominant arm at
randomized intensities including 3% body weight (BW), 4% BW, or 5% BW. Instantaneous
force data on the pedal axis was recorded and used to calculate the BLD. Data were analyzed
using a three-way ANOVA with factors of intensity (3% BW, 4% BW, and 5% BW), time
during the Wingate (1s – 10s, 11s – 20s, and 21s – 30 s), and position (1 o’clock position and 6
o’clock position). There was an overall BLD of -31.68 ± 21.20% (p <.001). The magnitude of
the bilateral index (BI) value was significantly affected by the intensity of the Wingate (p =.006),
and the time period of the Wingate (p<.001), but not the position. There were differences in the
magnitude of the BLD across intensities and time periods. Overall, a BLD in force exists during
maximal arm cycling Wingates and it is affected by fatigue and the movement velocity.
Increases in movement velocity decrease the magnitude of the BLD and increased amounts of
muscle fatigue likely increase the magnitude of the BLD
