Variability of motion in individuals with mechanical or functional ankle instability during a stop jump maneuver

Selection criteria for patients with chronic ankle instability in controlled research: a position statement of the International Ankle Consortium

The International Ankle Consortium is an international community of researchers and clinicians whose primary scholastic purpose is to promote scholarship and dissemination of research-informed knowledge related to pathologies of the ankle complex. The constituents of the International Ankle Consortium and other similar organizations have yet to properly define the clinical phenomenon known as chronic ankle instability (CAI) and its related characteristics for consistent patient recruitment and advancement of research in this area. Although research on CAI and awareness of its impact on society and healthcare systems have grown substantially in the last 2 decades, the inconsistency in participant/patient selection criteria across studies presents a potential obstacle to addressing the problem properly. This major gap within the literature limits the ability to generalize this evidence to the target patient population. Therefore, there is a need to provide standards for patient/participant selection criteria in research focused on CAI, with justifications using the best available evidence.

A systematic review and meta-analysis of dynamic tests and related force plate parameters used to evaluate neuromusculoskeletal function in foot and ankle pathology

BACKGROUND

Force plates are commonly used to register ground reaction forces in order to assess neuromusculoskeletal function of the ankle joint. There exists a great variety in dynamic tests on force plates and in parameters calculated from ground reaction forces in order to evaluate neuromusculoskeletal function of the ankle. The purpose of this study was to evaluate which dynamic tests and force plate parameters are most sensitive to differences between and within groups with regard to foot and ankle pathology.

METHODS

A systematic review and meta-analysis was performed evaluating studies that compared force plate parameters of dynamic tests between patients with foot and ankle pathology, and healthy controls. Data were pooled per parameter and test category. Given the clinical heterogeneity, we constructed comprehensive recommendation criteria to indicate a 'proven relevant parameter' or 'candidate relevant parameter'.

RESULTS

A total of 34 studies were included, and 58 relevant comparisons were identified. Results were subdivided by test category: walking, running, landing (in anteroposterior direction), sideways (movement in mediolateral direction) and termination (movement in anteroposterior direction). The 'walking' test showed significant differences in a great variety of pathologies, with the magnitude and timing of the 'second peak vertical force' as proven relevant parameters. The 'landing' test detected differences due to ankle instability, with 'time to stabilization in anteroposterior direction' as proven relevant parameter.

INTERPRETATION

This study provides recommendations concerning the potential of various dynamic tests and force plate parameters as a tool to compare neuromusculoskeletal function between patients with foot and ankle pathology and healthy controls.

Hip kinematics during a stop-jump task in patients with chronic ankle instability

CONTEXT

Chronic ankle instability (CAI) commonly develops after lateral ankle sprain. Movement pattern differences at proximal joints may play a role in instability.

OBJECTIVE

To determine whether people with mechanical ankle instability (MAI) or functional ankle instability (FAI) exhibited different hip kinematics and kinetics during a stop-jump task compared with "copers."

DESIGN

Cross-sectional study.

SETTING

Sports medicine research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Sixty-three recreational athletes, 21 (11 men, 10 women) per group, matched for sex, age, height, mass, and limb dominance. All participants reported a history of a moderate to severe ankle sprain. The participants with MAI and FAI reported 2 or more episodes of giving way at the ankle in the last year and decreased functional ability; copers did not. The MAI group demonstrated clinically positive anterior drawer and talar tilt tests, whereas the FAI group and copers did not.

INTERVENTION(S)

Participants performed a maximum-speed approach run and a 2-legged stop jump followed by a maximum vertical jump.

MAIN OUTCOME MEASURE(S)

An electromagnetic tracking device synchronized with a force plate collected data during the stance phase of a 2-legged stop jump. Hip motion was measured from initial contact to takeoff into the vertical jump. Group differences in hip kinematics and kinetics were assessed.

RESULTS

The MAI group demonstrated greater hip flexion at initial contact and at maximum (P = .029 and P = .017, respectively) and greater hip external rotation at maximum (P = .035) than the coper group. The MAI group also demonstrated greater hip flexion displacement than both the FAI (P = .050) and coper groups (P = .006). No differences were noted between the FAI and coper groups in hip kinematic variables or among any of the groups in ground reaction force variables.

CONCLUSIONS

The MAI group demonstrated different hip kinematics than the FAI and coper groups. Proximal joint motion may be affected by ankle joint function and laxity, and clinicians may need to assess proximal joints after repeated ankle sprains.

Principal component based analysis of biomechanical inter-trial variability in individuals with chronic ankle instability

BACKGROUND

Biomechanical variability during movement may influence joint stability in individuals with chronic ankle instability (CAI). The purpose of this study was to compare the kinematic and the kinetic inter-trial variability between healthy and CAI individuals.

METHODS

Eleven individuals with CAI and 11 matched controls performed five repetitions of a single-leg landing task. Biomechanical data were collected from 100 ms before to 200 ms after touchdown, and were used to calculate touchdown angles, peak angles and moments at the ankle joint in the frontal and sagittal planes. In addition, principal component analyses were used to quantify kinematic and kinetic patterns in the same planes across the 300 ms time window. Five trial averages and inter-trial variability were calculated for all variables for each subject. Independent t-tests were used to compare variables between groups.

FINDINGS

The CAI group displayed greater inter-trial variability for principal component scores in the sagittal and frontal planes. The sagittal plane principal component captured a phase shift in plantar-flexion motion before touchdown, while the frontal plane principal component captured the general magnitude of motion during the entire movement. The CAI group therefore exhibited greater inter-trial variability in the sagittal plane before touchdown and in the frontal plane during the entire movement.

INTERPRETATION

While average motions did not differ between groups, the CAI group displayed greater kinematic inter-trial variability when analyzed with the principal component analysis. More variable joint motions may indicate less dynamic stability in the CAI group, which may originate from greater ligamentous laxity or diminished neuromotor control.

Sway activity and muscle recruitment order during transition from double to single-leg stance in subjects with chronic ankle instability

Subjects with CAI (chronic ankle instability) are slower in activating their leg muscles when shifting weight (from double to single leg stance; DLS and SLS). We examined if these delays are associated with longer transition/stabilization times. This was tested by analyzing the center of pressure (COP) trajectory data (1) in the DLS phase before onset of transition, (2) in the quasi-stable phase of the SLS, immediately after the transition phase but before time to stabilization (TTS) and (3) in the SLS phase after TTS. Data were recorded from 20 subjects with CAI and 20 controls. The TTS was longer for the CAIs than for controls (3.25 vs. 2.28 s in EO and 3.41 vs. 2.51 s in EC; p<0.001). Similarly, the time of transition (TTR) was prolonged in CAIs (1.48 vs. 1.14 s in EO and 1.53 vs. 1.20 s in EC; p<0.05). These prolonged periods came in parallel with an increase in the ML sway in the quasi-stable phase (mean displacement 2.20 vs. 1.75 cm in EO; 3.37 vs. 2.62 cm in EC; significant for EC p<0.05). The TTR in CAIs was positively correlated with time onsets of the adductor longus muscle during transitions with EC (R=0.51, p=0.03). The findings support the use of a weight-shifting paradigm for the evaluation of balance control in CAI. Specifically, we underscore the transition phase and quasi-stable phase of the SLS as promising time windows for documenting balance control deficits in CAI.

Movement variability during single leg jump landings in individuals with and without chronic ankle instability

BACKGROUND

Repeated episodes of giving way at the ankle may be related to alterations in movement variability.

METHODS

Eighty-eight recreational athletes (39 males, 49 females) were placed in 4 groups: mechanically unstable, functionally unstable, copers, and controls based on ankle injury history, episodes of giving way, and joint laxity. Lower extremity kinematics and ground reaction forces were measured during single leg landings from a 50% maximum vertical jump in the anterior, lateral, and medial directions. Ensemble curves of 10 trials were averaged and coefficients of variation were identified for ankle, knee, hip, and trunk motion in 3 planes. A log(e) (ln) transformation was performed on the data. Mixed model analyses of variance (ANOVAs) with Tukey post-hoc tests were utilized with Bonferroni corrections to α ≤ 0.008.

FINDINGS

At the knee, controls were more variable than functionally unstable and copers for knee rotation before initial contact, and were more variable during stance than functionally unstable in knee rotation (P ≤ 0.008). Interactions during stance revealed controls were more variable than functionally unstable in lateral jumps for hip flexion, and than mechanically and functionally unstable in hip abduction in the anterior direction (P≤0.008). Controls were more variable than all other groups in hip flexion and than mechanically unstable in hip abduction (P ≤0 .008).

INTERPRETATION

Individuals with ankle instability demonstrated less variability at the hip and knee compared to controls during single leg jump landings. Inability to effectively utilize proximal joints to perform landing strategies may influence episodes of instability.

Foot clearance in walking and running in individuals with ankle instability

BACKGROUND

Foot positioning before heel strike has been attributed to chronic ankle instability injury mechanics, and may play a role in developing and perpetuating chronic ankle instability.

PURPOSE

This study was undertaken to determine if a group of individuals with mechanical instability (MI) or a group with functional instability (FI) of the ankle joint demonstrate less foot-floor clearance and a more inverted and plantar flexed position of the foot during the terminal swing phase of the running and walking cycles when compared with a group of ankle sprain copers who had an injury but no residual instability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Three-dimensional motion analysis was performed on 3 groups (n = 11 male athletes each) differentiated based on ankle injury history and ligamentous laxity during walking and running on a raised platform.

RESULTS

The MI group (14.8° ± 12.0°) demonstrated greater maximum foot external rotation than the FI (3.2° ± 6.0°) and coper groups (2.9° ± 11.0°) (P = .01; η(p) (2) = .25) during running and greater rotation than the coper group during walking (3.3° ± 6.1° vs -4.5° ± 4.1°; P = .03; η(p) (2) = .21). The FI group (6.1° ± 3.2°) had greater plantar flexion at minimum than the MI group (0.1° ± 3.5°) during walking (P = .02; η(p) (2) = .25). Other group differences demonstrated large effect sizes, but not statistical significance, including unstable groups having lower minimum metatarsal height than copers during running.

CONCLUSION

Differences in foot and leg position during terminal swing were observed between MI and FI groups and copers. Greater plantar flexion and lower minimum metatarsal height may increase risk for inadvertent contact and thus episodes of instability.

CLINICAL RELEVANCE

Rehabilitation programs may need to address terminal swing to improve mechanics and avoid potential episodes of giving way at the ankle.

Activity modulations of trunk and lower limb muscles during impact-absorbing landing

This study aimed to investigate the activity patterns of trunk and lower limb muscles during impact-absorbing landing. Electromyogram activities of the trunk and lower limb muscles along with kinematic and ground reaction forces were measured while subjects (n=17) performed 10 landings from a height of 35 cm. Landing motions were divided into three phases: 100 ms preceding ground contact (GC) (PRE phase), from GC through 100 ms (ABSORPTION phase), and from the end of the ABSORPTION phase until the vertical position of the center of mass was minimized (BRAKING phase). During the PRE phase, the rectus abdominis, external oblique, and medial gastrocnemius were highly activated. Upon GC, the hip and knee joints were in a flexed position; the ankle joints, in a plantarflexed position. After GC, peak timings of muscle activities and lower limb joint rotations were characterized by distal-to-proximal sequential patterns. The peak vertical ground reaction force in the ABSORPTION phase relative to body weight positively correlated with the activity levels of the vastus lateralis and gluteus maximus in the PRE phase and that of rectus abdominis in the ABSORPTION phase. These findings indicate that the intensities and peak timings of muscle activities in the trunk and lower limb are coordinated to absorb landing impact.