Ankle joint proprioception and postural control in basketball players with bilateral ankle sprains

Evaluation of joint position recognition measurement variables associated with chronic ankle instability: a meta-analysis

OBJECTIVE

To identify the most precise and consistent variables using joint repositioning for identifying joint position recognition (JPR) deficits in individuals with chronic ankle instability (CAI).

DATA SOURCES

We conducted a computerized search of the relevant scientific literature from January 1, 1965, to July 31, 2010, using PubMed Central, CINAHL, MEDLINE, SPORTDiscus, and Web of Science. We also conducted hand searches of all retrieved studies to identify relevant citations. Included studies were written in English, involved human participants, and were published in peer-reviewed journals.

STUDY SELECTION

Studies were included in the analysis if the authors (1) had examined JPR deficits in patients with CAI using active or passive repositioning techniques, (2) had made comparisons with a group or contralateral limb without CAI, and (3) had provided means and standard deviations for the calculation of effect sizes.

DATA EXTRACTION

Studies were selected and coded independently and assessed for quality by the investigators. We evaluated 6 JPR variables: (1) study comparisons, (2) starting foot position, (3) repositioning method, (4) testing range of motion, (5) testing velocity, and (6) data-reduction method. The independent variable was group (CAI, control group or side without CAI). The dependent variable was errors committed during joint repositioning. Means and standard deviations for errors committed were extracted from each included study.

DATA SYNTHESIS

Effect sizes and 95% confidence intervals were calculated to make comparisons across studies. Separate meta-analyses were calculated to determine the most precise and consistent method within each variable. Between-groups comparisons that involved active repositioning starting from a neutral position and moving into plantar flexion or inversion at a rate of less than 5°/s as measured by the mean absolute error committed appeared to be the most sensitive and precise variables for detecting JPR deficits in people with CAI.

Do the biomechanical properties of the ankle-foot complex influence postural control for people with Type 2 diabetes?

BACKGROUND

The ankle-foot complex plays an important role in the mechanics of postural control. The objectives of this study were to compare the biomechanical properties of the ankle-foot complex of people with diabetes who had or did not have peripheral neuropathy with those healthy individuals; and to examine its correlation with postural control.

METHODS

A total of 64 individuals participated in this study: 9 people with diabetic peripheral neuropathy, 23 diabetes without neuropathy, and 32 healthy controls. A hand-held ultrasound indentation system was used to assess the soft tissue biomechanical properties of the ankle-foot complex. The Sensory Organization test was performed using The Smart EquiTest system to assess postural control.

FINDINGS

The soft tissue of the Achilles tendon was significantly thickened in all individuals with diabetes (P<0.001), and was associated with the vestibular ratio (r=0.40; P<0.05). The Young's modulus of the plantar soft tissue was significantly increased in the diabetic neuropathy group (all P<0.05). Also, the Young's modulus of the plantar soft tissue at the first metatarsal head was positively correlated with the somatosensory ratio (r=0.46; P<0.05) and visual ratio (r=0.39; P<0.05).

INTERPRETATION

Diabetic patients with or without neuropathy had a thicker Achilles tendon and stiffer plantar soft tissue than the healthy control. Changes in the biomechanical properties of the ankle-foot complex were correlated with the use of vestibular, somatosensory or visual inputs to maintain balance in individuals with diabetes.

Training effects of two different unstable shoe constructions on postural control in static and dynamic testing situations

OBJECTIVE

The aim of this study was to compare training effects on postural control using two different unstable shoe constructions.

SUBJECTS AND SETTING

Twenty-nine healthy subjects participated in this study and were randomly divided into three groups. Two experimental groups (10 subjects in each group) were assigned to a 6 week training program of specific sensorimotor exercises with unstable shoe constructions, one group using MBT(®) shoes and one group wearing Reflex Control(®) shoes (RC). Subjects in the control group (9 subjects) did not perform balance training.

MAIN OUTCOME MEASURES

Postural control was measured in one-leg stance in two testing conditions. We recorded postural sway on a force plate (static testing situation) and displacements of a moveable platform (dynamic testing situation) before and after the training period.

RESULTS

There were no effects of training with unstable shoe constructions on postural sway in the static testing condition (for comparison of groups: p = 0.990 and p = 0.119). However, the RC group showed statistically significant improvements in the dynamic testing situation (p = 0.014 compared to control subjects). In the MBT group improvements were not significantly different in comparison to control group (p = 0.518).

CONCLUSIONS

Our results indicate that exercises using unstable shoe constructions, particularly the RC, improve postural control only in dynamic conditions.

Inclusion criteria when investigating insufficiencies in chronic ankle instability

INTRODUCTION

The development of chronic ankle instability (CAI) is the primary residual deficit after ankle joint sprain. It has been proposed that CAI is characterized by two entities, namely, mechanical instability and functional instability. Each of these entities in turn is composed of various insufficiencies. Research of functional insufficiencies to date has shown large variances in results. One particular reason for this could be discrepancies in inclusion criteria and definitions between CAI, mechanical instability, and functional instability used in the literature. Thus, we endeavored to undertake a systematic investigation of those studies published in the area of CAI to identify if there is a large discrepancy in inclusion criteria across studies.

METHODS

A systematic search of the following databases was undertaken to identify relevant studies: Cochrane Central Register of Controlled Trials, PubMed, CINAHL, SportDiscus, PEDro, and AMED.

RESULTS

The results of this study indicate that there is a lack of consensus across studies regarding what actually constitutes ankle instability. Furthermore, it is evident that the majority of studies use very different inclusion criteria, which leads to a nonhomogenous population and to difficulties when comparing results across studies.

CONCLUSIONS

Future studies should endeavor to be specific with regard to the exact inclusion criteria being used. Particular emphasis should be given to issues such as the number of previous ankle sprains reported by each subject and how often and during which activities episodes of "giving way" occur as well as the presence of concomitant symptoms such as pain and weakness. We recommend that authors use one of the validated tools for discriminating the severity of CAI. Furthermore, we have provided a list of operational definitions and key criteria to be specified when reporting on studies with CAI subjects.

Understanding acute ankle ligamentous sprain injury in sports

This paper summarizes the current understanding on acute ankle sprain injury, which is the most common acute sport trauma, accounting for about 14% of all sport-related injuries. Among, 80% are ligamentous sprains caused by explosive inversion or supination. The injury motion often happens at the subtalar joint and tears the anterior talofibular ligament (ATFL) which possesses the lowest ultimate load among the lateral ligaments at the ankle. For extrinsic risk factors to ankle sprain injury, prescribing orthosis decreases the risk while increased exercise intensity in soccer raises the risk. For intrinsic factors, a foot size with increased width, an increased ankle eversion to inversion strength, plantarflexion strength and ratio between dorsiflexion and plantarflexion strength, and limb dominance could increase the ankle sprain injury risk. Players with a previous sprain history, players wearing shoes with air cells, players who do not stretch before exercising, players with inferior single leg balance, and overweight players are 4.9, 4.3, 2.6, 2.4 and 3.9 times more likely to sustain an ankle sprain injury. The aetiology of most ankle sprain injuries is incorrect foot positioning at landing – a medially-deviated vertical ground reaction force causes an explosive supination or inversion moment at the subtalar joint in a short time (about 50 ms). Another aetiology is the delayed reaction time of the peroneal muscles at the lateral aspect of the ankle (60–90 ms). The failure supination or inversion torque is about 41–45 Nm to cause ligamentous rupture in simulated spraining tests on cadaver. A previous case report revealed that the ankle joint reached 48 degrees inversion and 10 degrees internal rotation during an accidental grade I ankle ligamentous sprain injury during a dynamic cutting trial in laboratory. Diagnosis techniques and grading systems vary, but the management of ankle ligamentous sprain injury is mainly conservative. Immobilization should not be used as it results in joint stiffness, muscle atrophy and loss of proprioception. Traditional Chinese medicine such as herbs, massage and acupuncture were well applied in China in managing sports injuries, and was reported to be effective in relieving pain, reducing swelling and edema, and restoring normal ankle function. Finally, the best practice of sports medicine would be to prevent the injury. Different previous approaches, including designing prophylactice devices, introducing functional interventions, as well as change of games rules were highlighted. This paper allows the readers to catch up with the previous researches on ankle sprain injury, and facilitate the future research idea on sport-related ankle sprain injury.

Evidence of sensorimotor deficits in functional ankle instability: a systematic review with meta-analysis

Functional ankle instability (FAI) has been associated with impaired sensorimotor function; however individual studies have produced conflicting results. In an attempt to reduce this ambiguity, a systematic review with meta-analysis was undertaken to determine which sensorimotor deficits exist with FAI. Fifty-three studies assessing sensorimotor factors in subjects with FAI were included from 465 identified articles. Studies were rated for methodological quality and data were pooled for peroneal reaction time, joint position sense, and postural sway during single-leg stance and time to stabilisation from a single-leg jump. Data on joint movement sense were unable to be pooled. When subjects with unstable ankles were compared to healthy controls, sensorimotor impairments were demonstrated for passive joint position sense (mean difference (MD)=0.7 degrees , 95% confidence interval (CI): 0.2-1.2 degrees , p=0.004), active joint position sense (MD=0.6 degrees , 95% CI: 0.2-1.0 degrees , p=0.002), postural sway in single-leg stance (standardised MD (SMD)=0.6, 95% CI: 0.2-1.0, p=0.002), the star excursion balance test (SMD=0.4, 95% CI: 0.1-0.7, p=0.009), and time to stabilisation from a single-leg jump in a medio-lateral (MD=0.6 ms, 95% CI: 0.4-0.8, p<0.0001) and an antero-posterior direction (MD=0.7 ms, 95% CI: 0.4-1.0, p<0.0001). Peroneal reaction time was not affected. Sensorimotor deficits occur for joint position sense and postural control in subjects with FAI. Deficits in peroneal muscle reaction time following perturbation are not evident.

Orthopaedic sport biomechanics - a new paradigm

This article proposes a new paradigm, "Orthopaedic sport biomechanics", for the understanding of the role of biomechanics in preventing and managing sports injury. Biomechanics has three main roles in this paradigm: (1) injury prevention, (2) immediate evaluation of treatment, and (3) long-term outcome evaluation. Related previous studies showing the approach in preventing and managing anterior cruciate ligament rupture and anterior talofibular ligament tear are highlighted. Orthopaedics and biomechanics specialists are encouraged to understand what they could contribute to the current and future practice of sports medicine.

Relationship between functional ankle instability and postural control

STUDY DESIGN

Controlled laboratory study using a cross-sectional design.

OBJECTIVES

To investigate the relationship between postural control and functional ankle instability during a hop-landing task, and to investigate whether postural control is altered in people with functional ankle instability.

METHODS AND MEASURES

Sixty volunteers classified by the Cumberland Ankle Instability Tool (CAIT) scores formed the external control group (CAIT score, >or= 28, n = 31) and the instability group (CAIT score, <or= 27 and history of at least 1 ankle sprain; n = 29). Postural control was measured with the landing test, in which participants stood on 1 lower extremity for 3 seconds on a step, then hopped down onto a force plate and regained postural stability after landing. The main outcome measurements were time to stability (TTS) after landing for ankle inversion, dorsiflexion, and summated electromyographic (EMG) signal amplitude for the tibialis anterior, soleus, and fibularis longus. The secondary outcomes were the proportion of movement in the frontal plane for hip and ankle, the variability of inversion movement prior to hopping, and the variables from ground reaction force.

RESULTS

There were no associations (P > .05) between the CAIT scores and the TTS for ankle inversion (r = -0.25), dorsiflexion (r = -0.04), summated EMG (r = -0.13) and proportion of movement in the frontal plane (r = 0.005). Participants in the instability group took longer to regain stability in inversion and displayed greater inversion variability prejump than the control group (P = .05 and .009, respectively).

CONCLUSIONS

Ankle inversion control is affected in people with functional ankle instability in tasks of postural control after landing from a hop.

The effect of immersion cryotherapy on medial-lateral postural sway variability in individuals with a lateral ankle sprain

BACKGROUND AND PURPOSE

Postural stability has been shown to be impaired after a lateral ankle sprain (LAS) and after immersion cryotherapy in healthy ankles. This study was performed to determine the effects of cryotherapy on postural stability after LAS.

METHOD

A single-session, repeated measures design was used. Fifteen 18- to 29-year-old males (mean age 21.33 +/- 3.54, height 71.23 +/- 2.50 cm, mass 170.33 +/- 19.77 kg) with relatively recent grade I LAS volunteered. Medial-lateral postural sway variability was assessed during single-leg barefoot stance using a Bertec force platform. Sway was tested before cryotherapy ('Pre'), immediately after 20 minutes of lower-leg immersion cryotherapy ('Post(0)'), and 10 and 20 minutes after cryotherapy ('Post(10)' and 'Post(20)'). Both legs were tested (individually) before cryotherapy; the involved leg was tested alone after cryotherapy. The uninvolved leg served as a control.

RESULTS

Postural sway variability of the involved le was significantly greater than the uninvolved le before cryotherapy (p = 0.001). Postural sway variability of the involved leg was also significantly greater than the uninvolved LE during Post(0) (p = 0.000), Post(10) (p = 0.000) and Post(20) testing (p = 0.003) with the largest increase in sway variability occurring at Post(0).

CONCLUSIONS

Medial-lateral postural sway variability was greater after LAS. This effect was augmented by immersion cryotherapy.

Sensorimotor deficits with ankle sprains and chronic ankle instability

The presence of sensorimotor deficits in patients who have suffered ankle sprains or who have chronic ankle instability has been recognized for several decades; however, a body of research literature has developed that elucidates potential physiologic explanations for these deficits. Alterations in a spectrum of sensorimotor measures make it apparent that conscious perception of afferent somatosensory information, reflex responses, and efferent motor control deficits are present with ankle instability. The specific origin of these deficits local to the ankle ligaments or at the spinal or supraspinal levels of motor control have yet to be fully elucidated. It is clear, however, that both feedback and feedforward mechanisms of motor control are altered with ankle instability.

Postural control measured as the center of pressure excursion in young female gymnasts with low back pain or lower extremity injury

Gymnasts are known to practice and compete although suffering from injuries and pain. Pain may change strategies for postural control. The primary aim of the present study was to investigate how center of pressure (COP) measurements are influenced by low back pain and lower extremity injury in top-level female gymnasts. A secondary aim was to study the reliability of these measurements using a test-retest design, and how this depends on the duration of the test. Fifty-seven top-level gymnasts were included in four groups: non-injured (NI, n=18), low back pain (LBP, n=11), lower extremity injury (LEI, n=17) and a multiple injury group (MI, n=11). COP excursion during quiet stance was measured on a force platform, during 120s: (1) hard surface/eyes open, (2) hard surface/eyes closed, (3) foam surface/eyes open and (4) foam surface/eyes closed. The COP excursion increased, for all groups, during the foam surface/eyes closed measurement compared to the other three tests. Furthermore, the LBP group showed a 49% (p=0.01) larger COP area compared to the LEI group in the foam surface/eyes closed condition. Measurements on foam surface were in general more reliable than tests on hard surface and tests with eyes closed were more reliable than tests with eyes open. Tests during 120s were in most cases more reliable than tests during 60s. In conclusion the COP excursion is influenced by injury location. Quiet stance measurements on foam surface with eyes closed seems to be reliable and sensitive in young female gymnasts.

Effects of dynamic head tilts on sensory organization test performance: a comparison between college-age athletes and nonathletes

STUDY DESIGN

Controlled laboratory study.

OBJECTIVE

To compare postural performance measures of athletes with those of nonathletes when completing the standard Sensory Organization Test (SOT) and a modified SOT that included dynamic head tilts (DHT-SOT).

BACKGROUND

Authors of recently published research have suggested that modifications to the SOT protocol (eg, introduction of pitch and roll head tilts) may enhance the test's sensitivity when assessing postural stability in individuals with higher balance capabilities or with well-compensated sensory deficits.

METHODS AND MEASURES

Nineteen athletes and 19 nonathletes (group) completed both the SOT and DHT-SOT (protocol). During the SOT, participants stood upright as steadily as possible for 20 seconds during each of 6 different sensory conditions. As a variation of the SOT, the DHT-SOT incorporated active pitch and roll head tilts into the SOT protocol. Four 2-way mixed-model analyses of variance (with protocol as the repeated factor) were performed to determine if the composite equilibrium score or the visual, vestibular, or somatosensory ratio scores differed between the 2 groups across the 2 testing protocols.

RESULTS

Significant group-by-protocol interaction effects were present for both the composite equilibrium score and visual ratio. Follow-up simple main-effects analyses indicated that these measures did not differ between groups for the SOT protocol but were significantly different on the DHT-SOT.

CONCLUSIONS

The addition of dynamic head tilts to the SOT protocol resulted in subtle differences in balance function between athletes and nonathletes. Athletes demonstrated an increased ability to adapt to sensory disruptions during the DHT-SOT. Therapists should consider including active pitch and roll head tilts to the SOT when evaluating individuals with higher balance function or to detect subtle deficits in balance function.

LEVEL OF EVIDENCE

Diagnosis, level 3b.

A new measurement method for spine reposition sense

Background

A cost effective tool for the measurement of trunk reposition sense is needed clinically. This study evaluates the reliability and validity of a new clinical spine reposition sense device.

Methods

The first part of this three part investigation included 45 asymptomatic subjects examined in the first 20 repeated trials portion assessing spine reposition sense. The second portion, test-retest, examined 57 asymptomatic subjects. Initial testing consisted of subjects sitting on the device and performing 20 trials of a self-determined 2/3 trunk flexion position. The second portion of the study involved 7 trials of trunk flexion performed twice. The angular position for each trial was calculated and the mean reposition error from the initial 2/3 position was determined. For the third portion, the new device was compared to the Skill Technologies 6D (ST6D) Imperial Motion Capture and Analysis System.

Results

ICC (3,1) for trials 4–7 was 0.79 and 0.76 for time one and time two, respectively and the test-retest ICC (3,k) was 0.38. Due to the poor test-retest ICC, the Bland Altman method was used to compare test and retest absolute errors. Most measurement differences were small and fell within the 95% confidence interval. Comparable measures between the two methods were found using the Bland Altman method to compare the reposition sense device to the ST6D system.

Conclusion

The device may be a cost effective clinical technique for sagittal trunk reposition sense measurement.

Possible factors related to functional ankle instability

STUDY DESIGN

Case control study.

OBJECTIVES

To classify individuals with functional ankle instability (FAI) into deficit and non-deficit categories based on the evaluation of the most common factors that have been proposed to be related to FAI.

BACKGROUND

Recent studies have suggested that FAI may be secondary to a combination of factors including ankle proprioceptive deficit, muscular weakness, impaired balance, delayed neuromuscular reaction time, and joint laxity. However, only a few authors have investigated the prevalence and association among these factors in a single group of individuals.

METHODS AND MEASURES

The above 5 factors were tested bilaterally in 21 individuals with FAI and in 16 healthy control subjects. Data were analyzed for (1) within- and between-group comparison, (2) classification of subjects with FAI into deficit and no-deficit categories, and (3) magnitude of association between factors in the subjects with FAI using Pearson bivariate correlation.

RESULTS

Balance control and evertors' strength were significantly less on the affected side in comparison to the unaffected side in subjects with FAI. The evertors' strength was also significantly different between the side difference of the FAI group and the side difference of the control group. Passive ankle stiffness was significantly correlated to balance control, ankle proprioception, and evertor peak torque. Individuals with FAI demonstrated a large variation in the deficit categories ranging from multiple deficits to no noticeable deficits.

CONCLUSION

Mechanical alterations in the ankle joint may influence several aspects of the ankle's functional ability. Alterations in the afferent processes, represented in this study by ankle proprioception, may effect the evertors' strength or vice versa. More importantly, individuals with FAI might exhibit high variability in ankle deficits.

Postural stability in altered and unaltered sensory environments following fatiguing exercise of lower extremity joints

Investigations of postural recovery following controlled external perturbations have provided models for healthy and pathological balance behavior. Less work, however, has investigated postural responses related to internal perturbations of the balance system. In this study, lower extremity joint (knee, or ankle) and overall fatigue of the dominant leg provided the internal perturbations to the balance system. Postural sway was examined during unilateral dominant leg standing before and immediately following fatiguing exercise, as well as at 10, 20, and 30 min post-fatigue activity. Sway was measured in both firm and sway-referenced support surface (external perturbation) conditions. Both joint-localized fatigue and overall fatigue were found to induce impairments in postural control, which were further exacerbated by external postural perturbations. Follow-up pairwise comparisons indicated that these impairments persisted at 10 and 30 min post-fatigue. No differences in postural sway were found between fatigue locations or across any interactions between sway and fatigue location. The results indicated that muscular fatigue imposed a prolonged internal perturbation to postural control, regardless of any individual or combined joint fatigue localization. This global effect, combined with the prolonged impairment in postural response, provides support for critical contributions from a central mechanism to postural deficits due to fatigue.

Modulation of Prelanding Lower-Limb Muscle Responses in Athletes with Multiple Ankle Sprains

PURPOSE

The objective of this study was to investigate modulation in prelanding muscle responses and its associated impact force on landing from unexpected and self-initiated drops in male basketball players with a history of bilateral multiple ankle sprains (BMAS).

METHODS

Prelanding EMG responses were recorded in four lower-limb muscles, together with the impact force on landing, while 20 healthy and 19 basketball players with BMAS performed unexpected, self-initiated drops from a height of 30 cm.

RESULTS

Group differences were detected after self-initiated but not unexpected drops. Two main changes in prelanding EMG responses were observed in the injured basketball players during the self-initiated drops. First, tibialis anterior (TA) was activated significantly earlier in the injured group, whereas left tensor fascia latae appeared closer to the moment of landing (P < 0.025) than in the healthy players. Second, cocontraction indexes between left TA and peroneus longus, and left TA and medial gastrocnemius, were significantly greater in the injured than in the healthy players (P < 0.025). On landing, higher magnitude-of-impact forces were observed in the injured players on the right leg (by 23%, P = 0.012).

CONCLUSION

In basketball players with BMAS, modulation of prelanding muscle response latencies occurred in injured (ankle) and uninjured (hip) joints during self-initiated but not unexpected drops. Greater cocontraction index between the left ankle muscle pairs in preparation for landing from self-initiated drops, and a significantly higher magnitude of impact force in the right leg on landing, were observed in the injured players.

Tongue-placed tactile biofeedback suppresses the deleterious effects of muscle fatigue on joint position sense at the ankle

Whereas the acuity of the position sense at the ankle can be disturbed by muscle fatigue, it recently also has been shown to be improved, under normal ankle neuromuscular state, through the use of an artificial tongue-placed tactile biofeedback. The underlying principle of this biofeedback consisted of supplying individuals with supplementary information about the position of their matching ankle position relative to their reference ankle position through electrotactile stimulation of the tongue. Within this context, the purpose of the present experiment was to investigate whether this biofeedback could mitigate the deleterious effect of muscle fatigue on joint position sense at the ankle. To address this objective, sixteen young healthy university students were asked to perform an active ankle-matching task in two conditions of No-fatigue and Fatigue of the ankle muscles and two conditions of No-biofeedback and Biofeedback. Measures of the overall accuracy and the variability of the positioning were determined using the absolute error and the variable error, respectively. Results showed that the availability of the biofeedback allowed the subjects to suppress the deleterious effects of muscle fatigue on joint position sense at the ankle. In the context of sensory re-weighting process, these findings suggested that the central nervous system was able to integrate and increase the relative contribution of the artificial tongue-placed tactile biofeedback to compensate for a proprioceptive degradation at the ankle.

Effect of isokinetic training on strength, functionality and proprioception in athletes with functional ankle instability

The purpose of this study was to investigate the effects of isokinetic exercise on strength, joint position sense and functionality in recreational athletes with functional ankle instability (FAI). Strength, proprioception and balance of 24 recreational athletes with unilateral FAI were evaluated by using isokinetic muscle strength measurement, ankle joint position sense and one leg standing test. The functional ability was evaluated using five different tests. These were; single limb hopping course (SLHC), one legged and triple legged hop for distance (OLHD-TLHD), and six and cross six meter hop for time (SMHT-CSMHT). Isokinetic peak torque of the ankle invertor and evertor muscles were assessed eccentrically and concentrically at test speeds of 120 degrees /s. Isokinetic exercise protocol was carried out at an angular velocity of 120 degrees /s. The exercise session was repeated three times a week and lasted after 6 weeks. At baseline, concentric invertor strength was found to be significantly lower in the functionally unstable ankles compared to the opposite healthy ankles (p < 0.001). This difference was not present after executing the 6 weeks exercise sessions (p > 0.05). Ankle joint position sense in the injured ankles declined significantly from 2.35 +/- 1.16 to 1.33 +/- 0.62 degrees for 10 degrees of inversion angle (p < 0.001) and from 3.10 +/- 2.16 to 2.19 +/- 0.98 degrees for 20 degrees of inversion angle (p < 0.05) following the isokinetic exercise. One leg standing test score decreased significantly from 15.17 +/- 8.50 to 11.79 +/- 7.81 in the injured ankles (p < 0.001). Following the isokinetic exercise protocol, all of the worsened functional test scores in the injured ankles as compared to the opposite healthy ankles displayed a significant improvement (p < 0.01 for OLHD and CSMHT, p < 0.001 for SLHC, TLHD, and SMHT). These results substantiate the deficits of strength, proprioception, balance and functionality in recreational athletes with FAI. The isokinetic exercise program used in this study had a positive effect on these parameters.

Generalizability of the sensory organization test in college-aged males: obtaining a reliable performance measure

OBJECTIVE

This study used generalizability theory to (1) determine the reliability of the six Sensory Organization Test (SOT) conditions, and (2) to determine the most effective testing schedule to obtain reliable posture measurements.

DESIGN

Generalizability theory was used to determine the most effecting testing protocol to obtain reliable assessments of postural sway in various sensory environments.

PARTICIPANTS

Twenty-five recreationally active college-aged males.

SETTING

University research laboratory.

INTERVENTIONS

None.

MAIN OUTCOME MEASUREMENTS

Postural stability as measured by equilibrium score (a percentage measure indicating amount of sway, with lower scores indicating a greater amount of postural sway). Scores were obtained for each of the six sensory conditions across multiple trials, tests, and days.

RESULTS

This study showed that performing the SOT twice on a single testing day was sufficient to achieve moderate to good reliability across the six conditions of the SOT. Extending SOT testing to twice on 2 days yielded good to excellent reliability estimates across all SOT conditions.

CONCLUSIONS

Taken together, these results indicate that for the purpose of monitoring changes in the postural control system, an individual needs to experience the full complement of SOT testing conditions at least twice. However, if highly reliable baseline measures of SOT performance are necessary, multiple tests performed on multiple days are warranted.

Are there any relationships among ankle proprioception acuity, pre-landing ankle muscle responses, and landing impact in man?

Proprioceptive input has been suggested to contribute to the pre-landing muscle responses associated with drop-landing, but its precise role has yet to be delineated. This study set out to examine the relationships among ankle proprioception, pre-landing muscle responses, and landing impact on drop-landing in healthy man. Fifteen healthy male basketball players aged 18 to 26 participated in this study. Passive ankle joint repositioning errors were used to examine ankle joint proprioception. Pre-landing EMG responses in the ankle muscles and the impact force on landing were recorded while the players performed self-initiated drops from a height of 30 cm. Results demonstrated that averaged ankle repositioning errors were significantly correlated with the co-contraction indexes between left tibialis anterior and medial gastrocnemius muscles (TA/MG CoI) (r=0.67, p=0.006), and showed a trend towards a relationship with the right TA/MG CoI (r=0.47, p=0.079). TA/MG CoI from both ankles were further related to the magnitude of the total impact force on landing (r=0.54 and 0.53, respectively; p<0.05). We concluded that male basketball players with less accurate ankle joint sense adopted greater co-contraction of ankle dorsiflexors and platarflexors, which was in turn associated with greater impact force at the moment of landing.

Rehabilitation of basketball injuries

Basketball is one of the most popular sports in the United States and throughout the world, and therefore represents one of the most common sources of sports-related injuries. Basketball injuries should be managed by the same general rehabilitation principles as other sports injuries. Additionally, the clinician should be aware not only of general sports injuries but of those injuries most commonly seen in basketball players. By maintaining knowledge of the most common basketball injuries as well as their diagnosis and treatment, the clinician can help to optimize the athlete's return to play and enjoyment of the sport.