RT Journal Article
SR Electronic
T1 Eccentric calf muscle exercise produces a greater acute reduction in Achilles tendon thickness than concentric exercise
JF British Journal of Sports Medicine
JO Br J Sports Med
FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine
SP 280
OP 283
DO 10.1136/bjsm.2008.053165
VO 43
IS 4
A1 Grigg, N L
A1 Wearing, S C
A1 Smeathers, J E
YR 2009
UL http://bjsm.bmj.com/content/43/4/280.abstract
AB Objective: To investigate the acute effects of isolated eccentric and concentric calf muscle exercise on Achilles tendon sagittal thickness.Design: Within-subject, counterbalanced, mixed design.Setting: Institutional.Participants: 11 healthy, recreationally active male adults.Interventions: Participants performed an exercise protocol, which involved isolated eccentric loading of the Achilles tendon of a single limb and isolated concentric loading of the contralateral, both with the addition of 20% bodyweight.Main outcome measurements: Sagittal sonograms were acquired prior to, immediately following and 3, 6, 12 and 24 h after exercise. Tendon thickness was measured 2 cm proximal to the superior aspect of the calcaneus.Results: Both loading conditions resulted in an immediate decrease in normalised Achilles tendon thickness. Eccentric loading induced a significantly greater decrease than concentric loading despite a similar impulse (−0.21 vs −0.05, p<0.05). Post-exercise, eccentrically loaded tendons recovered exponentially, with a recovery time constant of 2.5 h. The same exponential function did not adequately model changes in tendon thickness resulting from concentric loading. Even so, recovery pathways subsequent to the 3 h time point were comparable. Regardless of the exercise protocol, full tendon thickness recovery was not observed until 24 h.Conclusions: Eccentric loading invokes a greater reduction in Achilles tendon thickness immediately after exercise but appears to recover fully in a similar time frame to concentric loading.