Herve Collado and fellow researchers from France found that rehabilitation focusing at eccentric strengthening of ankle evertor muscles has shown to restore strength of first time lateral ankle sprain is better than concentric rehabilitation in lateral ankle sprain.
In the study, 18 subjects, aged 23-25 years who have type I and II lesion of the first time lateral sprain ankle, were randomized into two intervention groups, Concentric group (CG) and Eccentric group (EG). In addition, a control group consisting of 10 healthy subjects with no ankle sprain history and similar demographics are included.
The two interventions group underwent the same physical therapy treatment with the aim to reduce swelling of the ankle up to seven sessions. These treatments include draining the oedema, physiotherapy and retraining the range of motion. After the seventh session, the subjects would be subdivided into CG and EG to the twelve session. The subjects carried out 5 sets of 10 repetitions with two minutes interval on their respective concentric and eccentric strengthening of the ankle evertor muscles, followed by the same ankle proprioception training on a Freeman plate.
The subjects were tested with isokinetic dynamometer with their peak torque measured during pre treatment, on the sixth session and post treatment. The measurements were peak torques in the concentric and eccentric modes; ankle strength deficits, expressed as percentages of the healthy ankle values recorded in the concentric and eccentric modes; ratios between concentric/eccentric values.
Results showed that subjects in the eccentric group have ankle evertor muscles strength significantly greater but concentric group has significant deficits in both concentric and eccentric movement. This means that eccentric rehabilitation can help to restore the strength of the injured ankle evertor muscles which is crucial for better ankle stability. With better ankle stability, the incidence of recurrent ankle sprain will be reduced significantly.