Long-lasting unilateral muscle wasting and weakness following injury and immobilisation.

Quadriceps strength and size was measured in a small group of subjects (n = 7) 1 to 5 years after full mobilisation following some form of unilateral lower limb trauma. The mean maximum voluntary isometric force (MVC) was significantly lower for the injured (I) compared to the uninjured (UI) leg (369 N +/- 139 vs. 535 N +/- 131, p less than 0.01). Electrical stimulation superimposed on the voluntary contractions demonstrated that all subjects were able to maximally activate the quadriceps of both legs. Mean quadriceps cross-sectional area (CSA) was significantly lower in the I (64 cm2 +/- 12.8) compared to the UI leg (80 +/- 12.8, p less than 0.01). One subject with marked unilateral weakness and wasting took part in a 3-month strength training study for the injured leg. After training the I/UI ratio had been restored to nearly 100% (94% MVC; 88% CSA). These results would suggest that longer and more intensive physiotherapy is required in the immediate post-injury period to restore muscle strength and size to severely atrophied muscle.