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Free papers #4

Chronic Ankle Instability and postural control

Chair: TBA

#20 - Balance Performance in Child Futsal Athletes with Chronic Ankle Instability

Presenting Author: Supannikar Kadli

Authors & Affiliations: Supannikar Kadli(1), R Lekskulchai(1), Claire Hiller(2), C Jalayondeja(1)
(1)   Faculty of Physical Therapy, Mahidol University, Thailand
(2)    Faculty of Health Sciences, University of Sydney, Australia

Background: Ankle sprain is the most common ankle injury in futsal athletes. If perceived instability and / or recurrent sprain and / or mechanical instability develops or remains six months after an ankle sprain, it is considered chronic ankle instability (CAI). The athletes’ sport performance could be affected by their perceived instability. For futsal athletes, balance performance is crucial, they need to control the ball using both static and dynamic balance. Several studies reported that CAI could disturb adults’ balance performance but such studies in children are limited.

Objective(s): To compare static and dynamic balance performance among four groups of child futsal athletes with 1) bilateral CAI, 2) unilateral CAI, 3) ankle sprain history without CAI (coper) and 4) no ankle sprain history (control).

Design & Methods: Futsal athlete children (8-16 years) were recruited, interviewed and classified into the four groups. Static balance performance was tested by time of single leg standing on the floor and on foam with eyes opened- and eyes closed- for a maximum of 30 seconds in each condition. Dynamic balance performance was tested by the Star Excursion Balance Test (SEBT) in anterior, posterolateral and posteromedial directions. Best single leg stance duration was analysed by the Kruskal–Wallis test with Mann–Whitney U test post-hoc analysis. SEBT mean normalized reach distances (%) were analysed by one-way ANOVA with Bonferroni post-hoc analysis.

Results: Sixty-seven participants (13.7±1.9yrs; 45 males; 14 bilateral CAI, 23 unilateral CAI, 19 copers, 11 controls) were recruited. No demographics were different among groups except gender. For static balance only standing on foam with eyes open was significant with a difference between control (30s) and unilateral CAI groups (27.8s, p < 0.05). SEBT was significant in all directions. For posteromedial direction there was a significant difference between the control (66.9 ± 10.2) and all other groups (56.5±8.4, 53.4±8.4, 55.9±10.5, p< 0.001). For anterior and posterolateral directions, the difference was between control (76.7±9.2, 73.1±9.1) and unilateral CAI groups (65.5±7.8, 58.9±10.6, p< 0.05).

Conclusions: Futsal athlete children with unilateral chronic ankle instability showed significant static and dynamic balance impairment when compared with children without ankle sprain history. SEBT in the posteromedial direction could be used to distinguish impairments between uninjured and injured Futsal athlete children.


#21 - The effect of ankle braces on proprioception with and without a fatigued state of the body in patients with Chronic Ankle Instability between the ages of 18 – 35

Presenting Author: Yvon Hagoort

Authors & Affiliations: Yvon Hagoort(1), Ingrid Barelds(1)
(1)   Hanze University of Applied Sciences

Background: Chronic Ankle Instability, CAI, is one of the most common residual problems after an ankle injury. Joint proprioception plays an important role in maintaining functional stability of the joint. A fatigued state of the body is linked with a decreased joint position sense. Research has shown that braces are an effective method for the recurrence of an ankle sprain. However, the underlying working mechanism of this preventive effect of ankle bracing remains unclear. Furthermore, it is unclear whether fatigue influences the effect of braces on the joint position sense.

Objective(s): The main aim of the study is to investigate the effect of ankle braces on the ankle joint position sense with and without a fatigued state of the body in patients with Chronic Ankle Instability between the ages of 18 – 35

Design & Methods: Ankle proprioception was measured with and without a brace in both a fatigued state and an unfatigued state. Athletes with CAI (18-35 years) were included according to the selection criteria provided by the International Ankle Consortium. Joint Position Sense was measured using the Angle Reproduction test on the Humac Norm for 10o and 30o plantarflexion. To induce fatigue, participants ran on a treadmill for 5 minutes at 6.5 km/h, with an increase of 1km/h per minute till fatigued. Wilcoxon and Friedman test were used to compare the results with and without brace and the comparison between the braces.

Results: 12 subjects with CAI participated (age: 22.58 ± 2.9 years, length 177 ± 7.77 cm, body mass: 74.5 ± 12.7 kilograms, mean amount of injuries 3.25 ± 1.4 in total, CAIT 16.2 ± 4.5). A significant difference was found with and without a fatigued state of the body with the Exo – L brace at 30o of plantarflexion(Z=-2.394, p=.017). The mean error of degrees with a fatigued state of the body did not significantly change among the groups at 10o of plantarflexion (X2 (2) = 5.167, p = .075) and 30o of plantarflexion (X2 (2) = 0.409, p=.815).

Conclusions: Based on the results of this study, a brace has minimal to no effect on the JPS of the ankle in a fatigued state of the body. The relevance of this minimal effect still has to be examined.

#22 - Individuals with Chronic Ankle Instability demonstrate less variation in plantar force profile during walking, running and jumping movements

Presenting Author: Chris Bleakley

Authors & Affiliations: Chris Bleakley(1,2), B Mandry(1), S Swackhammer(1), Kevon Ford(1), T Brindle(1)
(1)   Department of Physical Therapy, Congdon School of Health Science, High Point University, North Carolina, USA
(2)    School of Health Science, Ulster University, County Antrim, Northern Ireland

Background: A healthy sensorimotor system allows individuals to adapt to various changes in environmental conditions and task demand. Chronic ankle instability (CAI) introduces an organismic constraint which can alter sensorimotor performance, however it is unclear how movement patterns are ultimately affected. Whilst some studies suggest CAI results in movement rigidity and predictably, others report movements become excessively variable and inconsistent. There is logic that both extremes could be deleterious for long term joint health. Much of the literature has examined biomechanical variability in open chain kinematics and step parameters, but few have considered variability at the body-environment interface.

Objective(s): The objective was to identify differences in stride-to-stride variability in plantar force profile during walking, running and side skipping between individuals with and without CAI. We hypothesized that participants with CAI would exhibit lower levels of variability than control participants across all movement tasks.

Design & Methods: We recruited 26 individuals with CAI and 24 healthy controls. The test limb for controls was randomly selected. Plantar loading parameters were collected using the Pedar-X in-shoe system (Novel, Germany) during four movement tasks: walking, jogging, side skipping (right and left). Maximum Force (% body weight) and Force Time Integral (% body weight) were extracted for each test. Variability was determined using SD across repeated ground contacts and the coefficient of variation (COV). Between group differences were examined using Cohen’s d (ES) and independent t tests. Secondary analyses were undertaken on the entire foot and for 7 anatomical regions (‘masks’).

Results: Individuals with CAI consistently demonstrated less intra-individual variability in FMax (%bw) and FTI (%bw), with moderate to large effect sizes noted during walking and jogging. CAI was also associated with less plantar force variability during side skipping, however this was only evident in the trail leg (not the lead leg). Secondary analyses found that the largest between group differences typically occurred at the foot region involved in initial contact eg. the heel mask during walking (ES 0.9 CI 95% 0.2-1.5, p=0.002) and the medial forefoot mask in the trail leg (ES 0.8 CI 95% 0.3-1.6, p=0.003) during side skips.

Conclusions: CAI is associated with less variable (more rigid) plantar force profile during walking, jogging and side skipping. The largest between group differences occurred in foot regions experiencing the initial ground contact. It may be that reduced sensory input during the open chain predicates a more rigid initial loading response.


#23 - Mechanical Ankle Instability Patients Suffer Insufficiencies of Vestibular System

Presenting Author: Yinghui Hua

Authors & Affiliations: Hongyun Li(1), Yinghui Hua(1)
(1)   Department of Sports Medicine, Huashan Hospital, Fudan University, Shanghai, China

Background: Previous researches indicated that patients with mechanical ankle instability (MAI) suffered deficits in postural control. Control of posture involves three input balance systems: visual, vestibular, and somatosensory systems.

Objective(s): The purpose of this study was to compare the difference in the three senses between MAI and normal control people.

Design & Methods: Twenty-two patients with MAI and 19 healthy control subjects were included in the study. MAI patients were diagnosed with lateral ankle ligaments rupture by magnetic resonance imaging, ultrasonography and arthroscopic evaluation. All participants performed standardized Sensory Organization Test (SOT) before the operation. The equilibrium and strategy scores were calculated. The sensory and strategy analyses were performed and compared between the 2 groups.

Results: The equilibrium scores for conditions 1,3,5 and 6 were significantly lower (P<0.05) in MAI group. Sensory analysis indicated that the ability to use input from vestibular system was decreased obviously in MAI group (P<0.01). No differences were found in the patient’s ability to use input from visual and somatosensory systems. The strategy score of SOT 5 was significantly lower (p<0.05) in MAI patients than in control participants, which indicated the increased use of hip strategy in unstable surface in MAI patients.

Conclusions: Patients with MAI suffer deficits in postural control. The ability to use input from vestibular system decreased and the ability to use hip strategy increased in MAI patients.


#24 - Effects of a single electrical stimulation strengthening session of the foot medial arch on intrinsic foot muscles strength and arch stability

Presenting Author: Romain Tourillon

Authors & Affiliations: Romain Tourillon(1,2,3), Boris Gojanovic(3), A Seurot(3), Francois Fourchet(3)
(1)   Faculty of Sport Sciences, University of Nantes, Nantes, France
(2)    School of Physiotherapy, IFM3R, Nantes, France
(3)    Motion Analysis Lab, Physiotherapy and Sports Medicine Department, La Tour Hospital, Meyrin, Switzerland

Background: The intrinsic foot muscles (IFM) are key foot stabilizers and are part of the active and neural components of the foot core system. Their anatomical insertions enable their role as dynamic support of the foot medial arch (FMA). Weakness of IFM has been linked to flexible flat foot and excessive pronation. In order to strengthen the IFM, neuromuscular electrical stimulation (NMES) has recently been proposed as a promising modality. However, to date, no studies have evaluated the effect of a single session of NMES on IFM strength and arch stability in healthy pronators.

Objective(s): To investigate the immediate effects of a single NMES strengthening session of the foot medial arch on IFM maximal strength and arch stability in subjects with static pronation of the foot.

Design & Methods: Forty-six healthy male and female volunteers with foot pronation (FPI >6) were randomly assigned to an experimental (n=23) or control (n=23) group. Participants in the experimental group received a single NMES strengthening session during 15 minutes on the dominant foot (abductor hallucis and FMA). Control group participants received a sham NMES (TENS) with similar modalities. Arch stability was assessed using “navicular drop” measurement (ND) while IFM maximal strength was assessed on a pressure platform while performing “short foot exercise” to the maximum. All the outcomes measurements were assessed pre- and post- intervention.

Results: The NMES group displayed a significant increase in IFM strength (5.1±1.0 N/kg vs 6.0±1.3 N/kg, p<0.01) and ND (8.0±2.7mm vs 6.6±2.9mm, p<0.01) while these did not change in the control group (5.0±1.0 N/kg vs 5.1 ±0.9 N/kg, p>0.05) and (7.2±2.3mm vs 7.3±2.3mm, p>0.05). 
We found effect sizes of 0.92 and 0.54 for IFM strength and arch stability between pre- and –post intervention in the NMES group on the dominant foot. No other significant effects in the non-dominant foot for groups were observed.

Conclusions: A single NMES session on FMA was effective at enhancing IFM strength and arch stability in subjects with static foot pronation. This supports the role of IFM electrical stimulation programmes in subjects with low arch, even without hypertrophic effect, in order to promote the strength of the FMA active stabilizers.


#25 - Unilateral drop jump landing biomechanics of individuals with and without chronic ankle instability

Presenting Author: Gabriel Moisan

Authors & Affiliations: Gabriel Moisan(1,2), Camille Mainville(1,3), Martin Descarreaux(1,3), Vincent Cantin(1,3)
(1)   Groupe de recherche sur les Affections Neuromusculosquelettiques (GRAN), Université du Québec à Trois-Rivières, QC, Canada
(2)    Department of Anatomy, Université du Québec à Trois-Rivières, QC, Canada
(3)    Department of Human Kinetics, Université du Québec à Trois-Rivières, QC, Canada

Background: Chronic ankle instability (CAI) is a condition that often occurs after sustaining a lateral ankle sprain. CAI has been associated with kinematic, kinetic and electromyographic (EMG) deficits during unilateral jump landing. However, few studies have investigated the unilateral jump landing biomechanical deficits for individuals with CAI on more challenging surfaces (e.g. unstable and inclined). It is necessary, as in real-life situations, CAI individuals can sprain their ankles on a variety of surfaces’ hardness or inclination. Better understanding the deficits associated with CAI during unilateral jump landing on these surfaces will ultimately help to develop a better treatment rehabilitation protocol.

Objective(s): The objective of this case-control study was to quantify the biomechanical (kinematic, kinetic and EMG) differences between individuals with and without CAI during unilateral drop landing on flat, inclined and unstable surfaces.

Design & Methods: Kinematic, kinetic and EMG data of 63 participants (32 CAI and 31 controls) were collected during unilateral drop landing on flat, 25 degrees laterally inclined and unstable (foam) surfaces. The participants completed five trials of all tasks. The dependant variables were ankle and knee angles and moments and gluteus medius, vastus lateralis, biceps femoris, gastrocnemius lateralis, fibularis longus and tibialis anterior muscles mean activity. Data were normalized to 100% of the preactivation (heel off to initial contact) and the landing (initial contact to maximal knee flexion) phases and were compared between groups with a one-dimensional statistical parametric mapping analysis.

Results: For the unilateral drop landing on a flat surface, the CAI group exhibited a decreased vastus lateralis muscle activity from 81 to 87% (p<0.01) of the preactivation phase compared to the healthy group. For the inclined surface, the CAI group exhibited an increased biceps femoris muscle activity from 33 to 56% (p<0.01) of the preactivation phase. Finally, for the unstable surface, the CAI group exhibited an increased ankle dorsiflexion from 77 to 88% (p=0.02) of the landing phase. No difference was observed between groups for the knee kinematics and the ankle and knee moments during all three tasks.

Conclusions: The results of this study show that biomechanical differences associated with CAI are task dependent and will help to better understand the underlying deficits associated with this pathology. Finally, the results of this study will help researchers and clinicians to better target the deficits associated with CAI during rehabilitation.


#26 - Neurocognition and Dynamic Postural Control in Collegiate Athletes with a History of Ankle Sprain

Presenting Author: Matthew Hoch

Authors & Affiliations: Mathew Hoch(1), Nicholas Heebner(1), Carolina Quintana(1), Reiley Bergin(1), Dong Han(1), John Abt(1)
(1)   University of Kentucky, Lexington, Kentucky, USA

Background: Athletes encounter a variety of complex situations that require strategic and split-second decisions under physical and cognitive stress. Cognitive domains including executive function, processing speed, and memory are critical for sorting and interpreting incoming images, prioritizing attention, and responding to rapidly changing environments. Poorer baseline neurocognitive function has been identified in athletes who sustained noncontact anterior cruciate ligament injuries which may have resulted from coordination errors or deficits in sensorimotor control. Neurocognitive function has not been thoroughly explored in athletes with a history of ankle sprain which may provide insight into recurrent injury mechanisms and novel rehabilitation strategies.

Objective(s): Compare neurocognitive function and dynamic postural control in collegiate athletes with and without a history of ankle sprain. We hypothesized that collegiate athletes with a history of ankle sprain would exhibit poorer neurocognitive function and dynamic postural control compared to collegiate athletes without a history of ankle sprain.

Design & Methods: A total of 107 collegiate athletes with (n=44) and without (n=63) a history of ankle sprain participated. Neurocognition was assessed using the NIH Toolbox subtests for executive function (Flanker Attention and Inhibitory Control), processing speed (Pattern Comparison Process Speed), and memory (Picture Sequence Memory Test). Fully-corrected standard scores (T-score) were calculated for all tests. Dynamic postural control was assessed using a hop stabilization task. Gyroscopic data were recorded using an inertial measurement unit. The root-mean-square of the resultant vector (RMS-RV) was calculated for three seconds upon single-limb landing. ANCOVAs and effect sizes (ES) were used for group comparisons.

Results: Collegiate athletes with a history of ankle sprain demonstrated poorer executive function (Ankle Sprain History: 46.28±10.20, No Ankle Sprain History: 50.58±10.58; p=0.04; ES=0.41±0.39) after controlling for gender, concussion history, and previous surgery. No significant differences were identified in processing speed (Ankle Sprain History: 62.04±9.27, No Ankle Sprain History: 63.10±9.21; p=0.56; ES=0.11±0.39), memory (Ankle Sprain History: 52.23±11.70, No Ankle Sprain History: 55.04±11.48; p=0.22; ES=0.24±0.39), or the RMS-RV (Ankle Sprain History: 88.84±37.45, No Ankle Sprain History: 92.50±37.37; p=0.63; ES=0.10±0.40).

Conclusions: Collegiate athletes with a history of ankle sprain demonstrated poorer executive function specifically related to visual attention and inhibitory control. Future studies should explore dynamic postural control assessments with integrated dual-task paradigms to assess the interaction between neurocognition and sensorimotor control in athletes with a history of ankle sprain.