Impact of a 2-Month Program of Eccentric Training on Plantar Flexor Structure and Function in Hemiparesis After...

To evaluate the effects of isokinetic eccentric training (ECC) in hemiparesis on plantar flexor muscle structure and function.

Randomized controlled trial.

Neurorehabilitation unit.

Twenty adult (N=20) community-dwelling outpatients with chronic stroke-induced hemiparesis (>6 mo) were recruited (n=10/group); median age: 59 (interquartile range [IQR], 55-64) years, sex: 15 men, 5 women; median time since lesion: 63 (IQR, 50-104) months.

Subjects were randomized into two 8-week rehabilitation programs: ECC group, involving 3 sessions/wk of plantar flexor ECC training, and a conventional group, with continuation of usual rehabilitation.

(1) Fascicle length and thickness of medial gastrocnemius (MG) and soleus (SOL), knee extended, at 80% maximal clinical extensibility of gastrocnemius in an isokinetic ergometer; (2) The MG and SOL agonist and antagonist electromyographic activity normalized to the amplitude of the maximum motor response during maximal isometric torques in plantar flexion and dorsiflexion; and (3) maximal barefoot 10-m ambulation speed. Parameters were collected by blinded evaluators at day 1 and week 8.

At week 8, significant between-group differences were observed for the ECC group, including: SOL fascicle length, +11.1 mm (P=.004, Rank-ANCOVA); SOL thickness: +1.9 mm (P=.007); MG thickness: +1.0 mm (P=.002); increased MG agonist recruitment: +0.015 (P=3 × 10^-4); and decreased MG cocontraction: -0.003 (P=.007). No between-group difference in ambulation speed, maximal torque, or neural command to SOL were observed.

In individuals with chronic hemiparesis, ECC training of plantar flexors is feasible and may improve their spastic myopathy, and command to gastrocnemius.