Affiliations: [a] Exercise and Sport Science Department, School of
Environmental and Life Sciences, University of Newcastle, Ourimbah, NSW, Australia
Note: [] Corresponding author: Robert Lockie, School of Environmental and
Life Sciences, University of Newcastle, PO Box 127, Ourimbah, NSW, 2258,
Australia. Tel.: +61 2 4349 4428; Fax: +61 2 4348 4145; E-mail:
robert.lockie@newcastle.edu.au
Abstract: This study analyzed relationships between bilateral concentric
(60°/s, 180°/s, 240°/s) and eccentric (30°/s) knee
extensor and flexor strength differences, and linear (40-meter sprint), and
change-of-direction (T-test) speed in 16 male team sport athletes. It was
hypothesized that lower between-leg strength differences would be associated
with faster speeds. Subjects were divided into faster and slower groups based
on total time; a one-way analysis of variance (p ⩽ 0.05) determined
bilateral torque and work differences that distinguished the groups. All data
was combined to correlate (p⩽ 0.05) torque and work differences with
sprint times. The faster group exhibited greater differences in concentric knee
extensor torque at 240°/s (faster=11.74 ± 8.65%; slower=
4.13 ± 4.34%), and smaller differences in eccentric knee flexor torque
(faster=5.64 ± 4.10%; slower=12.41 ± 7.55%) and work
(faster=6.36 ± 6.65%; slower=15.55 ± 6.05%). Negative
correlations were found between concentric 180°/s and 240°/s knee
extensor torque differences and sprint times; however, speed was not negatively
affected. Positive correlations existed between eccentric knee flexor work
differences and sprint times. Eccentric strength differences negatively
impacted multi-directional speed, as balanced eccentric strength is necessary
for effective sprinting, deceleration, and changing direction.
