Side-Alternating Vibration Training for Balance and Ankle Muscle Strength in Untrained Women

Abstract

Context: Side-alternating vibration (SAV) may help reduce the risk of falling by improving body balance control. Such training has been promoted as a strength-training intervention because it can increase muscle activation through an augmented excitatory input from the muscle spindles.Objective: To determine the effect of SAV training on static balance during 3 postural tasks of increasing difficulty and lower limb strength.Design: Randomized controlled clinical trial. Setting: Laboratory. Patients or Other Participants: A total of 21 healthy women were divided into training (n ¼ 11; age ¼ 43.35 6 4.12 years, height ¼ 169 6 6.60 cm, mass ¼ 68.33 6 11.90 kg) and control (n ¼ 10; age ¼ 42.31 6 3.73 years, height ¼ 167 6 4.32 cm, mass ¼ 66.29 6 10.74 kg) groups.Intervention(s): The training group completed a 9-week program during which participants performed 3 sessions per week of ten 15-second isometric contractions with a 30-second active rest of 3 exercises (half-squat, wide-stance squat, 1-legged half-squat) on an SAV plate (acceleration ¼ 0.91-16.3g). The control group did not participate in any form of exercise over the 9-week period.Main Outcome Measure(s): We evaluated isokinetic and isometric strength of the knee extensors and flexors and ankle plantar flexors, dorsiflexors, and evertors. Static balance was assessed using 3 tasks of increasing difficulty (quiet bipedal stance, tandem stance, 1-legged stance). The electromyographic activity of the vastus lateralis, semitendinosus, medial gastrocnemius, tibialis anterior, and peroneus longus was recorded during postural task performance, baseline and pretraining, immediately posttraining, and 15 days posttraining.Results: After training in the training group, ankle muscle strength improved (P ¼ .03), whereas knee muscle strength remained unaltered (P ¼ .13). Improved ankle-evertor strength was observed at all angular velocities (P ¼ .001). Postural sway decreased in both directions but was greater in the mediolateral (P , .001) than anteroposterior (P ¼ .02) direction. The electromyographic activity of the peroneus longus increased during the sharpened tandem (P ¼ .001) and 1-legged tasks (P ¼ .007). No changes were seen in the control group for any measures.Conclusions: The SAV training could enhance ankle muscle strength and reduce postural sway during static balance performance. The reduction in mediolateral sway could be associated with the greater use of ankle evertors due to their strength improvement.Key Words: whole-body vibration, posture, peroneus longus, ankle evertors Key PointsA 9-week, side-alternating vibration training program improved static balance control and postural stability, especially in the mediolateral direction. Side-alternating vibration improved ankle strength but not knee strength.

Effect of aging on the association between ankle muscle strength and the control of bipedal stance

“…It is interesting that although maximal muscle strength is not necessary for maintaining stability during bipedal stance, our results showed association between maximal strength of ankle muscles and postural sway during postural tasks. It seems that increased maximal strength is associated with greater capacity of muscles and possibility to increase muscle activity of the ankle muscles even during relatively simple postural tasks resulting in reduction of postural sway [15]. Other studies showed that strength training in older adults results in improvement of both neuromuscular performance and functional capacity of the subjects [41].…”

“…Other studies showed that postural control training strengthens the invertors and evertors [13], and that strength training besides improved muscle strength of all ankle muscle groups results in improved postural control [14]. In addition, greater use of ankle evertors owing to their improved strength could be associated with a reduction in mediolateral sway during sufficiently demanding postural tasks [15]. These findings suggest that the muscle strength of not only dorsal and plantar flexors but also invertors and evertors can be associated with level of postural control.…”

Whole-Body Vibration Combined with Treadmill Training Improves Walking Performance in Post-Stroke Patients: A Randomized Controlled Trial

“…The WBV in this study used side-alternating vibration that could evoke rotational movements around the hip and lumbo-sacral joints [ 15 ]. These rotational movements are controlled with the help of ankle evertors, which are important for lateral ankle stability [ 24 ]. Improved lateral ankle stability might increase single-limb support to the affected side.…”

Effect of Extracorporeal Shockwave Therapy on Passive Ankle Stiffness in Patients With Plantar Fasciopathy

“…This was performed at a constant angular velocity of 25 /s (27) (Fig); 25 /s is the speed typically recorded at the ankle joint during the stance phase of normal relaxed gait (28). The isokinetic torque of the ankle dorsiflexors and plantarflexors were measured with the mode of concentric/concentric contraction at the angular velocity of 60 /s (29,30). The measurements were performed by the same observer (C.-H. F.).…”