The Benefit of a Single-Leg Strength Training Program for the Muscles around the Untrained Ankle: A Prospective, Randomized, Controlled Study

Abstract

Severe ankle injuries can require extended periods of immobilization that adversely affect the strength of the ankle muscles. We have investigated a single-leg strength training program of the muscles surrounding the ankle to determine if it produces a crossover benefit for the contralateral ankle muscles. Twenty subjects without any history of ankle injuries were randomly divided into a control and a training group. Both groups underwent isokinetic testing of the ankle muscles at the beginning and end of an 8-week period. The control group maintained normal activities between the tests. Half of the training group trained the dominant leg only and the other half trained the nondominant leg only for the 8-week period, three times per week. The subjects who trained the dominant leg improved peak torque values by 8.5% in the trained leg and 1.5% in the untrained leg. Similarly, the subjects who trained the nondominant leg improved peak torque values by 9.3% in the trained leg and 3.5% in the untrained leg. In contrast, the control group showed no significant change in peak torque, power, or endurance between the initial and final tests. With improvements in peak torque as high as 40% in the trained leg and a crossover benefit of 19% in the untrained leg in eccentric inversion, this strength training technique deserves further investigation in an injured population where the benefits may be more substantial.

Ankle Strength and Force Sense After a Progressive, 6-Week Strength-Training Program in People With Functional Ankle Instability

“…These results agree with previous research demonstrating that strength training improved strength. 10,12,18,[38][39][40] Strengthtraining studies involving other joints provide further support for our results. At the shoulder, a 4-week TheraBand-and-lightweight-dumbbell protocol increased internal and external shoulder rotation torque.…”

“…Consistent with our results, strength improvements at the ankle have been reported with both a 6-week TheraBand protocol 10 and an 8-week isokinetic training protocol. 12 Bagheri et al 32 showed that 6 weeks of progressiveresistance-Thera-Band exercises increased muscle strength of the dorsiflexors, plantar flexors, evertors, and invertors. However, greater improvement (approximately 18.2%) was seen with plantar flexion and eversion.…”

“…5,[8][9][10][11][12][13][14][15][16][17] Strength-training exercises are used to increase muscular development and improve neuromuscular control. 10,[12][13][14][15]18 Previous researchers 19 demonstrated increased group Ia sensory activity after muscle contraction. Strength gains during the first 3 to 5 weeks of strength training are thought to be primarily due to neural factors.…”

Eccentric Plantar-Flexor Torque Deficits in Participants With Functional Ankle Instability

“…Specifically, strength training in one limb created increased peak torque in both the trained and untrained ankles. 27 It has yet to be determined if deficits in one limb could subsequently result in bilateral deficits; however, this issue needs to be further evaluated. Another consideration is that individuals prone to injury and subsequently to FAI may have an inherently suppressed ability to generate normal torques, which could predispose them to injury.…”

Effect of Ankle Stabilization Training Using Biofeedback on Balance Ability and Lower Limb Muscle Activity in Football Players with Functional Ankle Instability

“…Muscle strength training improves the control of nerve roots and increases muscle mass. 21 Strengthening of muscles activates the Ia group sense of muscles, activating functional muscle selectively and helps the function of antagonistic muscles. 22 Changes in the recruitment order of motor units caused by functional ankle instability causes nonfunctional and unnecessary movement in the joint and muscles as it is not able to activate muscles in the proper order.…”