Effect of six weeks of dura disc and mini-trampoline balance training on postural sway in athletes with functional ankle instability

Balance on different unstable supports: a complementary approach based on linear and non-linear analyses

Maintenance of postural control is a complex task that requires the integration of different sensory-motor processes. To improve postural control, balance training is often implemented using unstable surfaces. Little is known, however, about how different surfaces compare in terms of postural control strategy. Non-linear dynamical system analysis, like recurrent quantification analysis (RQA) applied to the center of pressure (CoP) trajectory, represents a useful tool in this respect. The aim of this study is to investigate the effects of different unstable supports on the CoP trajectory through a complementary approach based on linear and non-linear analyses. Seventeen healthy adults performed barefoot single-leg balance trials on a force plate and on three different balance training devices (soft disc, foam pad, and pillow). Sets of parameters were extracted from the CoP trajectories using classical stabilometric analysis (sway path, mean velocity, root mean square) and RQA (percent recurrence and determinism, maximum line length, entropy). Both classical and RQA analyses highlighted significant differences between stable (force plate) and unstable conditions (p < 0.001). Conversely, only classical stabilometric parameters showed significant differences among the considered balance training devices, indicating that the different characteristics of the devices do not influence the dynamic/temporal structure of the CoP trajectory. Analysis of the center of pressure trajectory during single-leg standing on three different balance training devices and on a rigid surface using both linear and non-linear techniques.

A Measurement of 'Walking-the-Wall' Dynamics: An Observational Study Using Accelerometry and Sensors to Quantify Risk Associated with Vertical Wall Impact Attenuation in Trampoline Parks

This study illustrates the application of a tri-axial accelerometer and gyroscope sensor device on a trampolinist performing the walking-the-wall manoeuvre on a high-performance trampoline to determine the performer dynamic conditions. This research found that rigid vertical walls would allow the trampolinist to obtain greater control and retain spatial awareness at greater levels than what is achievable on non-rigid vertical walls. With a non-rigid padded wall, the reaction force from the wall can be considered a variable force that is not constrained, and would not always provide the feedback that the trampolinist needs to maintain the balance with each climb up the wall and fall from height. This research postulates that unattenuated vertical walls are safer than attenuated vertical walls for walking-the-wall manoeuvres within trampoline park facilities. This is because non-rigid walls would provide higher g-force reaction feedback from the wall, which would reduce the trampolinist's control and stability. This was verified by measuring g-force on a horizontal rigid surface versus a non-rigid surface, where the g-force feedback was 27% higher for the non-rigid surface. Control and stability are both critical while performing the complex walking-the-wall manoeuvre. The trampolinist experienced a very high peak g-force, with a maximum g-force of approximately 11.5 g at the bottom of the jump cycle. It was concluded that applying impact attenuation padding to vertical walls used for walking-the-wall and similar activities would increase the likelihood of injury; therefore, padding of these vertical surfaces is not recommended.

Effectiveness of a Mini-Trampoline Training Program on Balance and Functional Mobility, Gait Performance, Strength, Fear of Falling and Bone Mineral Density in Older Women with Osteopenia

Purpose

To evaluate the effectiveness of a combined balance-, strength-, and jumping-exercise intervention on a mini-trampoline performed by older women with osteopenia on static balance and functional mobility, gait speed, strength of the upper and lower limbs, fear of falling, as well as to investigate its influence on bone mineral density (BMD).

Patient and methods

Using a randomized controlled study design, participants (range: 56-83 years) were assigned either to the intervention group (IG; n=20, mean age 69.6 ± 5.3 years) performing a specifically tailored intervention on a mini-trampoline or to the control group (CG; n=20, 67.4 ± 6.8 years), that did not undertake any intervention beyond regular osteopenia treatment. The intervention was performed twice a week for 12 weeks, each session lasting 45-60 mins and consisted of balance, strength and jumping exercises. Static balance and functional mobility was measured by one-leg stance (OLS) and timed up and go test (TUG). Upper and lower limb strength was evaluated by the arm curl test (ACT) and the 30-s chair stand test (CST) whereas gait speed was measured by the 6 m walking test (WT). Fear of falling was measured using the Falls Efficacy Scale - International (FES-I). BMD was measured at the lumbar spine and femoral neck using Dual-energy X-ray absorptiometry (DXA).

Results

Significant interactions (group x time) were found for all parameters (p<0.001) except for BMD, measured at the lumbar spine (p=0.064) and femoral neck (p=0.073). All test parameters of balance and functional mobility tests (OLS, TUG), strength tests (ACT, CST), WT, FES-I and BMD (femoral neck) showed significant improvement in the IG (p<0.05).

Conclusion

The combined 12-week intervention was highly effective in improving balance and functional mobility, strength, gait performance and fear of falling in patients with osteopenia.

Mini-trampoline enhances cardiovascular responses during a stationary running exergame in adults

A new class of video game called exergame (EXG) has been used to promote physical activity and cardiovascular fitness, but EXGs are not as efficient as traditional aerobic exercises. However, auxiliary tools, such as the mini trampoline (MT), may enhance the physiological responses obtained by the EXG. The aim of this study was to compare the metabolic and cardiovascular responses of a stationary running EXG with and without an MT. Nineteen healthy males performed a treadmill test for the determination of VO2max and HRmax. In sequence, the VO2, HR, and METs were measured during the Free Run, a Nintendo Wii's stationary running EXG, according to two distinct protocols. One protocol used the traditional EXG (EXG-PT), and the other protocol used an MT during the EXG (MT-PT). The normalized data were analyzed by statistical software SPSS 20.0 using a t-test and ANOVA for repeated measures (p < 0.05). The results supported that stationary running EXG performed on an MT showed an increased intensity, in all variables analyzed, when compared with the traditional EXG. Furthermore, the MT-PT was classified as a vigorous-intensity exercise and EXG-PT as a moderate to vigorous intensity exercise. In conclusion, these findings support that the MT is a feasible auxiliary tool to enhance physiologic responses during a stationary running EXG.

Balance- and Strength-Training Protocols to Improve Chronic Ankle Instability Deficits, Part I: Assessing Clinical Outcome Measures

CONTEXT

  Functional rehabilitation may improve the deficits associated with chronic ankle instability (CAI).

OBJECTIVE

  To determine if balance- and strength-training protocols improve the balance, strength, and functional performance deficits associated with CAI.

DESIGN

  Randomized controlled clinical trial.

SETTING

  Athletic training research laboratory.

PATIENTS OR OTHER PARTICIPANTS

  Participants were 39 volunteers with CAI, which was determined using the Identification of Functional Ankle Instability Questionnaire. They were randomly assigned to 1 of 3 groups: balance-training protocol (7 males, 6 females; age = 23.5 ± 6.5 years, height = 175.0 ± 8.5 cm, mass = 72.8 ± 10.9 kg), strength-training protocol (8 males, 5 females; age = 24.6 ± 7.7 years, height = 173.2 ± 9.0 cm, mass = 76.0 ± 16.2 kg), or control (6 males, 7 females; age = 24.8 ± 9.0 years, height = 175.5 ± 8.4 cm, mass = 79.1 ± 16.8 kg).

INTERVENTION(S)

  Each group participated in a 20-minute session, 3 times per week, for 6 weeks. The control group completed a mild to moderately strenuous bicycle workout.

MAIN OUTCOME MEASURE(S)

  Participants completed baseline testing of eccentric and concentric isokinetic strength in each ankle direction (inversion, eversion, plantar flexion, and dorsiflexion) and the Balance Error Scoring System (BESS), Star Excursion Balance Test (SEBT), and side-hop functional performance test. The same variables were tested again at 6 weeks after the intervention. Two multivariate repeated-measures analyses of variance with follow-up univariate analyses were conducted. The α level was set a priori at .05.

RESULTS

  We observed time-by-group interactions in concentric ( P = .02) and eccentric ( P = .01) inversion, eccentric eversion ( P = .01), concentric ( P = .001) and eccentric ( P = .03) plantar flexion, BESS ( P = .01), SEBT ( P = .02), and side hop ( P = .004). With pairwise comparisons, we found improvements in the balance- and strength-training protocol groups in concentric and eccentric inversion and concentric and eccentric plantar flexion and the BESS, SEBT, and side hop (all P values = .001). Only the strength-training protocol group improved in eccentric eversion. The control group did not improve in any dependent variable.

CONCLUSIONS

  Both training protocols improved strength, balance, and functional performance. More clinicians should incorporate hop-to-stabilization exercises into their rehabilitation protocols to improve the deficits associated with CAI.

Oxygen uptake during mini trampoline exercise in normal-weight, endurance-trained adults and in overweight-obese, inactive adults: A proof-of-concept study

OBJECTIVES

To examine cardiorespiratory exertion during mini trampoline exercises of different intensities in both endurance-trained athletes and overweight-obese adults.

METHODS

Physically healthy participants (Group A: normal-weight, endurance-trained athletes; Group B: inactive, overweight-obese adults) participated in two measurement appointments and three training sessions in between appointments, in which participants familiarized themselves with the use of the mini trampoline and the execution of the exercises. The primary outcome was the ⩒O_2peak for each of the six mini trampoline exercises relative to the ⩒O_2peak as established during an all-out exercise test on a bike ergometer during the first measurement appointment. Secondary outcomes were average ⩒O₂ as well as maximum and average heart rate.

RESULTS

The six mini trampoline exercises generated ⩒O_2peak values between 42% and 81% in the endurance-trained athletes and between 58% and 87% in the overweight-obese participants, both in relation to the bike ergometer ⩒O_2peak. Average ⩒O₂ values ranged from 35% to 69% (endurance-trained athletes) and from 48% to 71% (overweight-obese participants), depending on exercise. Average heart rate likewise lay in a range that can be categorized as moderate-to-vigorous aerobic exercise for both groups. A moderate-to-strong correlation (0.658 to 0.875, depending on exercise) between bike ergometer ⩒O_2peak and mini trampoline ⩒O_2peak was found for all six exercises.

CONCLUSIONS

Mini trampoline exercise has the potential to produce training intensities that concur with established exercise guidelines. The exercise intensity is self-adjusting and allows for an effective and safe workout for different users with a wide range of fitness levels.

Effects of weight-bearing exercise on a mini-trampoline on foot mobility, plantar pressure and sensation of diabetic neuropathic feet; a preliminary study

Objective: Foot and ankle exercise has been advocated as a preventative approach in reducing the risk of foot ulceration. However, knowledge about the appropriate types and intensity of exercise program for diabetic foot ulcer prevention is still limited. The current study aimed to examine the effects of an eight-week mini-trampoline exercise on improving foot mobility, plantar pressure and sensation of diabetic neuropathic feet.

Methods: Twenty-one people with diabetic peripheral neuropathy who had impaired sensation perception were divided into two groups. The exercise group received a foot-care education program plus an eight-week home exercise program using the mini-trampoline (n = 11); whereas a control group received a foot-care education only (n = 10). Measurements were undertaken at the beginning, at the completion of the eight-week program and at a 20-week follow-up.

Results: Both groups were similar prior to the study. Subjects in the exercise group significantly increased the range of the first metatarsophalangeal joint in flexion (left: p = 0.040, right: p = 0.012) and extension (left: p = 0.013) of both feet more than controlled subjects. There was a trend for peak plantar pressure at the medial forefoot to decrease in the exercise group (p = 0.016), but not in the control group. At week 20, the number of subjects in the exercise group who improved their vibration perception in their feet notably increased when compared to the control group (left: p = 0.043; right: p = 0.004).

Conclusions: This is a preliminary study to document the improvements in foot mobility, plantar pressure and sensation following weight-bearing exercise on a flexible surface in people with diabetic neuropathic feet. Mini-trampoline exercise may be used as an adjunct to other interventions to reduce risk of foot ulceration. A larger sample size is needed to verify these findings. This trial is registered with COA No. 097.2/55.

The physiological, musculoskeletal and psychological effects of stand up paddle boarding

Background

Stand up paddle boarding (SUP) is a rapidly growing sport and recreational activity where anecdotal evidence exists for its proposed health, fitness and injury rehabilitation benefits. While limited scientific evidence exists to substantiate these claims, previous studies have shown that high levels of fitness, strength and balance exists amongst participants of this sport. The purpose of this study was to conduct a training intervention on a group of previously untrained individuals to ascertain the potential of SUP on various health parameters.

Methods

An intervention study was conducted where after being tested initially, subjects were left for 6 weeks to act as their own control before the SUP intervention began. A total of 13 SUP participants completed the training study (nine males, four females) which was comprised of three 1 h sessions per week for 6 weeks.

Results

No significant changes occurred during the initial control period. Significant (P < 0.05) improvements were made in aerobic (+23.57 %) and anaerobic fitness (+41.98 %), multidirectional core strength tests (prone +19.78 %, right side +26.19 %, left side +28.31 %, Biering Sorensen +21.33 %) and self-rated quality of life questionnaires in the physical (+19.99 %) and psychological (+17.49 %) domains. No significant changes were detected in static or dynamic balance over the duration of the training intervention.

Conclusion

These results demonstrate the cardiovascular, musculoskeletal and psychological improvements achievable for the novice when utilizing SUP as a training tool. The result from this study provides some evidence to substantiate the claims of health and fitness benefits SUP.

Changes in Postural Control After a Ball-Kicking Balance Exercise in Individuals With Chronic Ankle Instability

CONTEXT

Rehabilitation programs for patients with chronic ankle instability (CAI) generally involve balance-perturbation training (BPT). Anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) are the primary strategies used to maintain equilibrium during body perturbations. Little is known, however, about how APAs and CPAs are modified to promote better postural control for individuals with CAI after BPT.

OBJECTIVE

To investigate the effect of BPT that involves kicking a ball on postural-control strategies in individuals with CAI.

DESIGN

Randomized controlled clinical trial.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

We randomly assigned 44 volunteers with CAI to either a training group (TG; 11 women, 11 men; age = 24 ± 4 years, height = 173.0 ± 9.8 cm, mass = 72.64 ± 11.98 kg) or control group (CG; 11 women, 11 men; age = 22 ± 3 years, height = 171.0 ± 9.7 cm, mass = 70.00 ± 11.03 kg).

INTERVENTION(S)

The TG performed a single 30-minute training session that involved kicking a ball while standing on 1 foot. The CG received no intervention.

MAIN OUTCOME MEASURE(S)

The primary outcome was the sum of the integrated electromyographic activity (∑∫EMG) of the lower extremity muscles in the supporting limb that were calculated during typical intervals for APAs and CPAs. A secondary outcome was center-of-pressure displacement during similar intervals.

RESULTS

In the TG after training, the ∑∫EMG decreased in both dorsal and ventral muscles during compensatory adjustment (ie, the time interval that followed lower limb movement). During this interval, muscle activity (∑∫EMG) was less in the TG than in the CG. Consequently, center-of-pressure displacement increased during the task after training.

CONCLUSIONS

A single session of ball-kicking BPT promoted changes in postural-control strategies in individuals with CAI. These results should stimulate new and more comprehensive studies to investigate the effect of this and other BPT techniques on postural control in patients with CAI.

Anticipatory and Compensatory Postural Adjustments in Response to External Lateral Shoulder Perturbations in Subjects with Parkinson's Disease

The purpose of this study was to investigate the anticipatory (APA) and compensatory (CPA) postural adjustments in individuals with Parkinson’s disease (PD) during lateral instability of posture. Twenty-six subjects (13 individuals with PD and 13 healthy matched controls) were exposed to predictable lateral postural perturbations. The electromyographic (EMG) activity of the lateral muscles and the displacement of the center of pressure (COP) were recorded during four time intervals that are typical for postural adjustments, i.e., immediately before (APA1, APA2) and after (CPA1 and CPA2) the postural disturbances. The magnitude of the activity of the lateral muscles in the group with PD was lower only during the CPA time intervals and not during the anticipatory adjustments (APAs). Despite this finding, subjects with PD exhibit smaller COP excursions before and after the disturbance, probably due to lack of flexibility and proprioceptive impairments. The results of this study suggest that postural instability in subjects with PD can be partially explained by decreased postural sway, before and after perturbations, and reduced muscular activity after body disturbances. Our findings can motivate new studies to investigate therapeutic interventions that optimize the use of postural adjustment strategies in subjects with PD.

The effect of modified trampoline training on balance, gait, and falls efficacy of stroke patients

[Purpose] This research was conducted to investigate the effects of modified trampoline training on the balance, gait, and falls efficacy of stroke patients. [Subjects] Twenty-four stroke patients participated in this study. The subjects were randomly allocated to one of two groups: the trampoline group (n=12) or the control group (n=12). [Methods] Both groups participated in conventional physical therapy for thirty minutes per day, three times a week for six weeks. The trampoline group also took part in trampoline training for thirty minutes per day, three times a week for six weeks. We evaluated balance (Berg balance scale, timed up and go test), gait (dynamic gait index), and falls efficacy (falls efficacy scale-K) to confirm the effects of the intervention. [Results] Both the trampoline and the control group showed significant improvements in balance, gait, and falls efficacy compared to before the intervention, and the improvements were significantly greater in the trampoline group than in the control group. [Conclusion] Modified trampoline training resulted in significantly improved balance, dynamic gait, and falls efficacy of stroke patients compared to the control group. These results suggest that modified trampoline training is feasible and effective at improving balance, dynamic gait, and falls efficacy after stroke.

Strength, Multijoint Coordination, and Sensorimotor Processing Are Independent Contributors to Overall Balance Ability

For young adults, balance is essential for participation in physical activities but is often disrupted following lower extremity injury. Clinical outcome measures such as single limb balance (SLB), Y-balance (YBT), and the single limb hop and balance (SLHB) tests are commonly used to quantify balance ability following injury. Given the varying demands across tasks, it is likely that such outcome measures provide useful, although task-specific, information. But the extent to which they are independent and contribute to understanding the multiple contributors to balance is not clear. Therefore, the purpose of this study was to investigate the associations among these measures as they relate to the different contributors to balance. Thirty-seven recreationally active young adults completed measures including Vertical Jump, YBT, SLB, SLHB, and the new Lower Extremity Dexterity test. Principal components analysis revealed that these outcome measures could be thought of as quantifying the strength, multijoint coordination, and sensorimotor processing contributors to balance. Our results challenge the practice of using a single outcome measure to quantify the naturally multidimensional mechanisms for everyday functions such as balance. This multidimensional approach to, and interpretation of, multiple contributors to balance may lead to more effective, specialized training and rehabilitation regimens.

Neuromuscular control and rehabilitation of the unstable ankle

Lateral ankle sprain is a common orthopedic injury with a very high recurrence rate in athletes. After decades of research, it is still unclear what contributes to the high recurrence rate of ankle sprain, and what is the most effective intervention to reduce the incident of initial and recurrent injuries. In addition, clinicians often implement balance training as part of the rehabilitation protocol in hopes of enhancing the neuromuscular control and proprioception of the ankle joint. However, there is no consensus on whether the neuromuscular control and proprioception are compromised in unstable ankles. To reduce the prevalence of ankle sprains, the effectiveness of engaging balance training to enhance the neuromuscular control and proprioception of the ankle joint is also questionable.

Lower extremity biomechanics in athletes with ankle instability after a 6-week integrated training program

CONTEXT

Plyometric exercise has been recommended to prevent lower limb injury, but its feasibility in and effects on those with functional ankle instability (FAI) are unclear.

OBJECTIVE

To investigate the effect of integrated plyometric and balance training in participants with FAI during a single-legged drop landing and single-legged standing position.

DESIGN

Randomized controlled clinical trial.

SETTING

University motion-analysis laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty athletes with FAI were divided into 3 groups: plyometric group (8 men, 2 women, age = 23.20 ± 2.82 years; 10 unstable ankles), plyometric-balance (integrated)-training group (8 men, 2 women, age = 23.80 ± 4.13 years; 10 unstable ankles), and control group (7 men, 3 women, age = 23.50 ± 3.00 years; 10 unstable ankles).

INTERVENTION(S)

A 6-week plyometric-training program versus a 6-week integrated-training program.

MAIN OUTCOME MEASURE(S)

Postural sway during single-legged standing with eyes open and closed was measured before and after training. Kinematic data were recorded during medial and lateral single-legged drop landings after a 5-second single-legged stance.

RESULTS

Reduced postural sway in the medial-lateral direction and reduced sway area occurred in the plyometric- and integrated-training groups. Generally, the plyometric training and integrated training increased the maximum angles at the hip and knee in the sagittal plane, reduced the maximum angles at the hip and ankle in the frontal and transverse planes in the lateral drop landing, and reduced the time to stabilization for knee flexion in the medial drop landing.

CONCLUSIONS

After 6 weeks of plyometric training or integrated training, individuals with FAI used a softer landing strategy during drop landings and decreased their postural sway during the single-legged stance. Plyometric training improved static and dynamic postural control and should be incorporated into rehabilitation programs for those with FAI.

Exergaming and static postural control in individuals with a history of lower limb injury

CONTEXT

Therapeutic exercise programs that incorporate real-time feedback have been reported to enhance outcomes in patients with lower extremity joint injuries. The Wii Fit has been purported to improve balance, strength, flexibility, and fitness.

OBJECTIVE

To determine the effects of Wii Fit rehabilitation on postural control and self-reported function in patients with a history of lower limb injury.

DESIGN

Single-blinded, randomized controlled trial.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty-eight physically active participants with a history of lower limb injuries were randomly assigned to 1 of 3 groups (9 Wii Fit, 10 traditional, 9 control).

INTERVENTION(S)

Intervention groups performed supervised rehabilitation 3 d/wk for a total of 12 sessions.

MAIN OUTCOME MEASURE(S)

Time to boundary (TTB) and the Star Excursion Balance Test (SEBT) were conducted at baseline, 2 weeks, and 4 weeks. Self-reported function was measured at baseline and 4-week follow-up. Between-groups differences were compared using repeated-measures multivariate analysis of variance.

RESULTS

With the eyes open, both intervention groups improved (P < .05) in the mean and the SD of the TTB anterior-posterior minima. In the eyes-closed condition, a time main effect (P < .05) for absolute TTB medial-lateral minima was observed. A time main effect was also noted in the posteromedial and posterolateral reach directions of the SEBT. When the scores for each group were pooled, improvement (P < .05) in self-reported function was demonstrated at 4-week follow-up.

CONCLUSIONS

Rehabilitation using the Wii Fit and traditional exercises improved static postural control in patients with a history of lower extremity injury.

Structural changes in postural sway lend insight into effects of balance training, vision, and support surface on postural control in a healthy population

Postural sway was assessed [via center of pressure (COP) 95% elliptical area (EA), path length (PL), normalized path length (PL(n)) and sample entropy (SEn)] in four conditions of bipedal upright stance [compliant (Foam) vs. non-compliant (Hard) with eyes-open (EO) vs. eyes-closed (EC)] prior to, and immediately following, a six-week balance training intervention in a group of healthy adults (N = 26). The intervention was comprised of nine exercises progressed in difficulty based on the subjective assessments of individual competency. Results showed that EA and PL were increased, while PL(n) and SEn were decreased, in EC and Foam stance conditions (collapsed across effects of balance training). Interpretations were that restricted vision and a compliant surface represented constraints to postural control that caused increases in the amount (PL) and area (EA) of sway, but decreases in its coordinative twisting/turning (PL(n)) and temporal complexity (SEn). It was argued that these changes might represent compensatory adaptations in effort to maintain postural control given the demands of the imposed constraints. Balance training caused no change to EA, but did result in decreased PL, PL(n), and SEn for stance conditions performed on the Foam (either EO or EC). These changes were interpreted to reflect improved postural control, potentially through the learned adoption of a more deterministic postural control strategy that is uniquely defined by the constraints imposed on upright stance by the compliant surface.

Effect of sensorimotor training on morphological, neurophysiological and functional characteristics of the ankle: a critical review

Sensorimotor training is effective in preventing ankle sprain recurrences, but the pathway through which this effect occurs is unknown. Biomechanical and neurophysiological analyses of sensorimotor training leading to functional changes of the ankle are needed to establish this pathway. This article reviews the effect of sensorimotor training on morphological, neurophysiological and functional characteristics of the ankle. A MEDLINE and CINAHL computerized literature search was conducted to search for relevant articles. A study was included if (i) the study contained research questions regarding the effect of sensorimotor training on mechanical, neurophysiological, and/or functional ankle functioning; (ii) the study dealt with subjects with a history of ankle sprain; (iii) the study contained a control group; (iv) the results contained measures of mechanical, neurophysiological or functional insufficiencies as study outcome; and (v) the study met a predefined cut-off score set for methodological quality. Results on joint position sense and muscle reaction times showed a learning effect of repeated measures and not a training effect. Decrements of postural sway after sensorimotor training were mainly attributable to a learning effect as well. Effects on muscle strength were not found. Evidence for an effect of sensorimotor training on neurophysiological, morphological and functional characteristics is limited, if present at all. Thus, the pathway of sensorimotor training remains unclear. Future studies need to focus on (i) differentiating between morphological, physiological and functional changes; (ii) larger sample sizes with a priori sample size calculations; (iii) correspondence between training and test method; (iv) using measures other than postural sway more closely linked to functional stability; and (v) using a longer follow-up period than 6 weeks.

Treatment of common deficits associated with chronic ankle instability

Lateral ankle sprains are amongst the most common injuries incurred by athletes, with the high rate of reoccurrence after initial injury becoming of great concern. Chronic ankle instability (CAI) refers to the development of repetitive ankle sprains and persistent residual symptoms post-injury. Some of the initial symptoms that occur in acute sprains may persist for at least 6 months post-injury in the absence of recurrent sprains, despite the athlete having returned to full functional activity. CAI is generally thought to be caused by mechanical instability (MI) or functional instability (FI), or both. Although previously discussed as separate entities, recent research has demonstrated that deficits associated with both MI and FI may co-exist to result in CAI. For clinicians, the main deficits associated with CAI include deficits in proprioception, neuromuscular control, strength and postural control. Based on the literature reviewed, it does seem that subjects with CAI have a deficit in frontal plane ankle joint positional sense. Subjects with CAI do not appear to exhibit any increased latency in the peroneal muscles in response to an external perturbation. Preliminary data suggest that feed-forward neuromuscular control may be more important than feed-back neuromuscular control and interventions are now required to address deficits in feed-forward neuromuscular control. Balance training protocols have consistently been shown to improve postural stability in subjects with CAI. Subjects with CAI do not experience decreased peroneus longus strength, but instead may experience strength deficits in the ankle joint invertor muscles. These findings are of great clinical significance in terms of understanding the mechanisms and deficits associated with CAI. An appreciation of these is vital to allow clinicians to develop effective prevention and treatment programmes in relation to CAI.