Athletes trained using stable compared to unstable surfaces exhibit distinct postural control profiles when assessed by traditional and nonlinear measures

The optimal method for improving postural balance in healthy young and older people: specific training for postural tasks encountered in personal physical practice

It is well known that regular exercise or physical activity (training) improves postural balance in healthy young and older subjects, but the optimal exercise or physical activity (i.e., likely to induce the greatest postural improvements) and the context in which it is carried out remain to be explored and determined for each population. The most beneficial adaptations would depend, in particular, on gestural conditions (body position, movement and gesture practiced) and material conditions (nature of the ground surface, sports equipment used, type of environment - stable or changing). In fact, the global postural adaptations induced by training do not result from the transfer between different trained and untrained postural tasks, but are the sum of the adaptations related to each trained postural task in healthy young and older subjects. Based on current knowledge, optimal training programs should include the full range of postural tasks encountered in personal physical practice for each population. To date, the method of implementing progressive postural balance tasks with different degrees of difficulty and instability has been used as the effective method to improve postural balance, but it should not be considered as the reference method. Instead, it should be considered as a complementary method to the one based on specific postural tasks. An intervention strategy is proposed for young and older adults consisting of three different steps (general, oriented and specific/ecologic training). However, some parameters still need to be explored and possibly reconsidered in future studies to improve postural balance in an optimal way.

Decision-Making Time and Neuromuscular Coordination in Youth and Senior Soccer Goalkeepers

The aim of this study was to compare soccer goalkeepers' decision-making times following a shot on goal and to determine goalkeepers' movement pattern structures using EMG in a typical game situation (two-on-one). Two groups of goalkeepers (n = 60) took part in the study: Group A, the senior group (22.00 ± 2.35 years of age), and Group B, the youth group (15.38 ± 1.32 years of age). The goalkeepers' decision-making times were measured by using EMG from the moment the attacker struck the ball until the completion of the saving action by the goalkeeper. Subsequently, the goalkeepers' movement pattern structure was determined (for both Groups A and B), and the values of muscle bioelectrical tension during a typical defensive situation in training conditions were revealed. The findings clearly indicate a significantly (p = 0.001) shorter decision-making time in experienced goalkeepers (250-260 ms) than in novices (300-320 ms). In addition, the movement pattern structure confirmed the hypotheses on the economization of effort and the visual-muscular coordination of the postural muscles (calf muscles) that affect soccer goalkeepers. The study also demonstrated a lower bioelectric tension of the gastrocnemius muscle (GAS.MED. RT-p = 0.008; GAS.LAT. RT-p = 0.030) in the expert goalkeepers.

The Importance of Posture And Body Composition for the Stability and Selected Motor Abilities of Professional Handball Players

The aim of the research was to analyze body composition, body posture and postural stability of professional male handball players and to determine the differences between players with correct and incorrect body posture, considering power of the lower limbs and agility, speed, and change of direction deficit. The study comprised 16 professional handball players. Body composition analysis was performed using the method of electrical bioimpedance. Body posture was examined using the Diers formetric III 4D optoelectronic method. Postural stability was tested via the Biodex Balance System. Players performed the following fitness tests assessing lower limb muscle power (LP, HS, CMJ), linear speed (SLS 20 m), and COD speed (Zig-Zag test, COD deficit). Only 31.25% of players demonstrated body posture with correct physiological curvatures, while 68.75% showed changes in body asymmetry. The group with correct body posture performed better in SLS 20m than the group with incorrect posture, yet in the Zig-Zag agility test, the difference in the results was not significant and this affected the COD deficit, which was higher. The vast majority of participants demonstrated postural defects and incorrect physiological curvatures of the spine. The occurrence of scoliotic posture was also observed. The body deflection angles indicated that athletes’ postural stability was good. However, it is worth noting that the majority demonstrated a tendency towards asymmetrical body deflections to the right or to the left, backwards direction. One-sided sports specialization leads to disturbances in the statics of the body, therefore, it becomes necessary to include postural re-education exercises in training.

Different Gymnastic Balls Affect Postural Balance Rather Than Core-Muscle Activation: A Preliminary Study

Background: In proprioceptive training, unstable devices produce multidirectional perturbations that must be counterbalanced by the postural control systems and core-muscle activation. We investigated whether different sizes and shapes of three gymnastic balls could affect core-muscle activation and postural balance when performing the same exercise. Methods: Eleven young healthy subjects were assessed on the balls, assuming two body postures (bipedal seated and unipedal seated) and performing a dynamic exercise. Two balls were spherical with different diameters, and one was ovoid. Postural balance and muscle activation were assessed through center of pressure (CoP)-related parameters and surface electromyography. Results: Statistical analysis showed a significant effect of the gymnastic balls (p < 0.001) and the body postures (p < 0.001) for the CoP-related parameters, with the ovoid shape and the bipedal sitting representing the easiest conditions. Core-muscle activation was affected only by body postures, with a higher activation in the unipedal sitting (p < 0.01). In the dynamic exercise, significant differences were only detected for the CoP-related parameters (p < 0.001). Conclusions: The shapes and sizes of the gymnastic balls produced different degrees of destabilization under the same body posture but left the core-muscle activation unaltered. In the dynamic exercise, the conformation of the balls did not represent the main determinant in producing destabilizing effects.

Baseline Postural Control and Lower Extremity Injury Incidence Among Those With a History of Concussion

CONTEXT

Lower extremity musculoskeletal (LEMSK) injury may be more prevalent among those with a history of sport-related concussion (SRC).

OBJECTIVE

To investigate the relationship between baseline postural control metrics and the LEMSK injury incidence in National Collegiate Athletic Association Division I student-athletes with a history of SRC.

SETTING

National Collegiate Athletic Association Division I athletes.

DESIGN

Cohort study.

PATIENTS OR OTHER PARTICIPANTS

Of 84 total athletes (62 males), 42 had been previously diagnosed with an SRC, and 42 were matched controls based on age, sex, height, weight, and sport.

MAIN OUTCOME MEASURE(S)

During the preseason baseline evaluation, all participants performed 3 trials of eyes-open and eyes-closed upright quiet stance on a force platform. Medical charts were assessed for all the LEMSK injuries that occurred from preseason baseline to 1 year later. Center-of-pressure data in the anteroposterior and mediolateral directions were filtered before we calculated root mean square and mean excursion velocity; the complexity index was calculated from the unfiltered data. Factorial analysis-of-variance models were used to examine differences between groups and across conditions for root mean square; mean excursion velocity, complexity index, and tests of association to examine between-groups LEMSK differences; and logistic regression models to predict LEMSK.

RESULTS

Concussion history and injury incidence were related in the SRC group (P = .043). The complexity index of the SRC group was lower with eyes closed (14.08 ± 0.63 versus 15.93 ± 0.52) and eyes open (10.25 ± 0.52 vs 11.80 ± 0.57) in the mediolateral direction than for the control participants (P < .05). Eyes-open root mean square in the mediolateral direction was greater for the SRC group (5.00 ± 0.28 mm) than the control group (4.10 ± 0.22 mm). Logistic regression models significantly predicted LEMSK only in control participants.

CONCLUSIONS

These findings may suggest that LEMSK after SRC cannot be predicted from postural-control metrics at baseline.

Important Movement Concepts: Clinical Versus Neuroscience Perspectives

Human movement is complex, presenting clinical and research challenges regarding how it is described and investigated. This paper discusses the commonalities and differences on how human movement is conceptualized from neuroscientific and clinical perspectives with respect to postural control; the limitations of linear measures; movement efficiency with respect to metabolic energy cost and selectivity; and, how muscle synergy analysis may contribute to our understanding of movement variability. We highlight the role of sensory information on motor performance with respect to the base of support and alignment, illustrating a potential disconnect between the clinical and neuroscientific perspectives. The purpose of this paper is to discuss the commonalities and differences in how movement concepts are defined and operationalized by Bobath clinicians and the neuroscientific community to facilitate a common understanding and open the dialogue on the research practice gap.

The effects of total ankle arthroplasty on postural stability and loading symmetry in quiet stance

Ankle osteoarthritis is a debilitating condition affecting about 1% of the population with approximately 50,000 new instances annually. One treatment is total ankle arthroplasty (TAA), however, its effects on balance are not well understood. This study analyzed balance over a two-year period following TAA. 408 subjects (177 left, 231 right ankles) diagnosed with end-stage ankle osteoarthritis performed quiet standing trials while center of pressure (COP) data were collected. Data were compared across three time points (pre-op, 1-year, and 2-years post-op) and between surgical and non-surgical limbs using a linear mixed model with significance set at P = 0.05. COP excursions in the feet-together condition were not significantly different between limbs after 2 years in anteroposterior or mediolateral directions (P = 0.06, 0.08) after being significantly different between limbs in the anteroposterior (P = 0.014) and mediolateral direction (P < 0.001) pre-op. The vertical ground reaction force significantly decreased across time in the non-surgical limb, while reciprocally increasing in the surgical limb (P < 0.001). After 2 years, no significant difference in vertical ground reaction force between limbs existed (P = 0.20). Limb asymmetry indices decreased at each time point in both conditions (all P < 0.001) and were not significantly different from zero after 2 years in the feet-together condition (P = 0.290). In conclusion, surgical limb balance improved compared to pre-op, resulting in increased symmetry between limbs after 2 years. Vertical ground reaction forces on both limbs converge and limb asymmetry indices approach zero two years post-op. Differences in the COP excursion-loading symmetry relationship between limbs could be useful for identifying instability in other pathologies.

Transitions sit to stand and stand to sit in persons post-stroke: Path of centre of mass, pelvic and limb loading - A pilot study

BACKGROUND

To explore the movement patterns utilized by persons post stroke from the simultaneous perspective of pelvic and limb loading with the path of centre of mass during the movement transitions sit to stand and stand to sit.

METHODS

A descriptive pilot study where kinetic and kinematic data were collected and compared between the contribution made by the less affected versus more affected lower limb and trunk during sit to stand and stand to sit following stroke. Movement analysis was undertaken using force-plates and a 3D VICON motion capture system.

FINDINGS

Data were successfully collected on nine subjects of whom four presented with left side more affected and eight were male. Two patterns were demonstrated for pelvic loading, four patterns for limb loading and five patterns for deviation of centre of mass. There were no consistent patterns of movement demonstrated dependent upon the more or less affected side. There was no consistent relationship between pelvic and limb loading and deviation of centre of mass throughout the movement phases.

INTERPRETATION

In contrast to assumptions often made with respect to limb loading, we found large variability in movement patterns utilized by person's with a hemiparetic presentation during sit to stand and stand to sit. The findings suggest that movement problems encountered by persons post-stroke are complex and identifies limitations with respect to current measurement techniques.

Postural Stability in Goalkeepers of the Polish National Junior Handball Team

The aim of the study was to assess postural stability of goalkeepers from the Polish national junior handball team. Eleven juniors of the Polish national handball team (age 16.82 ± 1.6 years, body height 191.27 ± 3.1 cm, body mass 88.41 ± 12.26 kg, BMI 24.18 ± 3.22 kg/m2) were selected for the study. The Biodex Balance System and AccuGait AM¬TI platform were used to evaluate postural stability. The obtained results indicated good postural stability of the subjects. During the Biodex Balance System platform tests, all subjects presented very good postural stability and maintained within Zone A. Postural sway was greater in the sagittal plane compared to the frontal one. Most of the participants demonstrated slight backward tilts, but maintained in Quadrant IV. During the AccuGait AMTI platform trial, Path Length and Average COP Speed significantly increased in the test performed with closed eyes. Furthermore, there were significant positive correlations between the number of variables obtained during the Biodex Balance System and AccuGait AMTI tests. Proper and stable posture are necessary conditions to be met to carry out most free movements and locomotion. They play a significant role in the game of a handball goalkeeper and for that reason, postural stability testing of handball goalkeepers is an important element of coordination training. Thus, the use of postural stability exercises implementing the biofeedback method on stabilo and dynamometric platforms is practical and justifiable.

Conceptualizing movement by expert Bobath instructors in neurological rehabilitation

RATIONALE, AIMS, AND OBJECTIVES

Movement, a core aspect of physiotherapy practice, and integral to the clinical reasoning process has undergone limited theoretical development. Instead, research has focused on intervention effectiveness embedded within the positivist paradigm. The purpose of this study was to explore how expert neurorehabilitation therapists conceptualize movement as part of their clinical reasoning.

METHOD

A qualitative interpretive descriptive approach consisting of stimulated recall using video-recorded treatment sessions and in-depth interviews was used. Theoretical sampling was used to recruit members of the International Bobath Instructors Training Association (IBITA) who are recognized experts in neurorehabilitation. Interview transcripts were transcribed verbatim. Data analysis was progressive, iterative, and inductive.

RESULTS

Twenty-two IBITA instructors from 7 different countries volunteered to participate. They ranged in clinical experience from 12 to 40 years and instructor experience from 1 to 35 years. The conceptualization of movement by the IBITA instructors involves the following elements: (1) movement comprises the whole person and the whole body, not just individual body segments; (2) active alignment of body segments is integral to movement performance; and (3) efficient movement requires the relative integration of postural control/stability and selective movement/mobility.

CONCLUSIONS

The IBITA instructors conceptualize movement from a person-centred perspective. The integration of postural control and selective movement, with alignment and variability as key components, forms the foundation of their understanding of movement. Further investigation into the role of postural control in movement recovery post central nervous system lesion is required. Likewise, the dimensions of movement critical to the conceptualization of movement are not well understood from the perspective of the physiotherapist or persons with neurological impairments.

Center of pressure profiles in unilateral compared to bilateral end-stage ankle osteoarthritis patients

Ankle osteoarthritis (OA) compromises ankle joint stability in regards to static balance. Unilateral and bilateral osteoarthritis patients often exhibit different limb-loading patterns during static balance tasks. Symmetrical loading has been posited to improve balance performance. Therefore, the purpose of this study was to quantify balance performance in both ankle osteoarthritis patient groups. Twenty-two unilateral and twenty-one bilateral ankle osteoarthritis patients performed three 10-s quiet standing trials with their feet together. Ground reaction force data were collected from force platforms with one under each foot. Center of pressure excursion in the anteroposterior and mediolateral directions as well as the resultant center of pressure were calculated using custom Matlab software. A 2 × 2 repeated measures ANOVA with Cohen's d were used to analyze the differences between groups (unilateral vs. bilateral) and between limbs (affected vs. unaffected) (α = 0.05). No significant differences were found between limbs or groups in either the anteroposterior or mediolateral direction for any measured variable. Though not statistically different, moderate to large effect sizes were observed for mean resultant distance between unilateral and bilateral (d = 0.096, d: 1.0) as well as anteroposterior excursion (p = 0.077, d: 1.731) and mean velocity (p = 0.084, d: 1.50) between affected and unaffected limbs. These large effect sizes suggested clinically relevant differences may exist, particularly in the anteroposterior direction. These findings may suggest that center of pressure is a better measure of postural strategy while center of mass measures may be more representative of postural steadiness. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2749-2754, 2017.

Directing clinical care using lower extremity biomechanics in patients with ankle osteoarthritis and ankle arthroplasty

Ankle osteoarthritis is a debilitating disease with approximately 50,000 new cases per year leading to skeletal deformity, severe and recurrent pain, cartilage breakdown, and gait dysfunction limiting patient mobility and well-being. Although many treatments (total ankle arthroplasty [TAA], ankle fusion [arthrodesis], and ankle distraction arthroplasty) relieve pain, it is not clear that these procedures significantly improve patient mobility. The goal of the research presented here is to summarize what is presently known about lower extremity gait mechanics and outcomes and to quantify the impact of ankle osteoarthritis and TAA have on these measures using an explicitly holistic and mechanistic approach. Our recent studies have explored physical performance and energy recovery and revealed unexpected patterns and sequelae to treatment including incomplete restoration of gait function. These studies demonstrated for the first time the extreme levels and range of gait and balance dysfunction present in ankle osteoarthritis patients as well as quantifying the ways in which the affected joint alters movement and loading patterns not just in the painful joint, but throughout both the ipsilateral and contralateral lower extremity. Through this work, we determined that relieving pain alone through TAA is not enough to restore normal walking mechanics and balance due to underlying causes including limited ankle range of motion and balance deficits leading to long-term disability despite treatment. The results indicate the need to consider additional therapeutic interventions aimed at restoring balance, ankle range of motion, and movement symmetry in order to improve long-term health and function. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2345-2355, 2017.

Repetitive head impacts do not affect postural control following a competitive athletic season

Evidence suggests that Repetitive Head Impacts (RHI) directly influence the brain over the course of a single contact collision season yet do not significantly impact a player's performance on the standard clinical concussion assessment battery. The purpose of this study was to investigate changes in static postural control after a season of RHI in Division I football athletes using more sensitive measures of postural control as compared to a non-head contact sports. Fourteen Division I football players (CON) (age=20.4±1.12years) and fourteen non-contact athletes (NON) (2 male, 11 female; age=19.85±1.21years) completed a single trial of two minutes of eyes open quiet upright stance on a force platform (1000Hz) prior to athletic participation (PRE) and at the end of the athletic season (POST). All CON athletes wore helmets outfitted with Head Impact Telemetry (HIT) sensors and total number of RHI and linear accelerations forces of each RHI were recorded. Center of pressure root mean square (RMS), peak excursion velocity (PEV), and sample entropy (SampEn) in the anteroposterior (AP) and mediolateral (ML) directions were calculated. CON group experienced 649.5±496.8 mean number of impacts, 27.1±3.0 mean linear accelerations, with ≈1% of total player impacts exceeded 98g over the course of the season. There were no significant interactions for group x time RMS in the AP (p=0.434) and ML (p=0.114) directions, PEV in the AP (p=0.262) and ML (p=0.977) directions, and SampEn in the AP (p=0.499) and ML (p=0.984) directions. In addition, no significant interactions for group were observed for RMS in the AP (p=0.105) and ML (p=0.272) directions, PEV in the AP (p=0.081) and ML (p=0.143) directions, and SampEn in the AP (p=0.583) and ML (p=0.129) directions. These results suggest that over the course of a single competitive season, RHI do not negatively impact postural control even when measured with sensitive non-linear metrics.

Athletes who train on unstable compared to stable surfaces exhibit unique postural control strategies in response to balance perturbations

BACKGROUND

Athletes have been shown to exhibit better balance compared to non-athletes (NON). However, few studies have investigated how the surface on which athletes train affects the strategies adopted to maintain balance. Two distinct athlete groups who experience different types of sport-specific balance training are stable surface athletes (SSA) such as basketball players and those who train on unstable surfaces (USA) such as surfers. The purpose of this study was to investigate the effects of training surface on dynamic balance in athletes compared to NON.

METHODS

Eight NON, eight SSA, and eight USA performed five 20-s trials in each of five experimental conditions including a static condition and four dynamic conditions in which the support surface translated in the anteroposterior (AP) or mediolateral (ML) planes using positive or negative feedback paradigms. Approximate entropy (ApEn) and root mean square distance (RMS) of the center of pressure (CoP) were calculated for the AP and ML directions. Four 3 × 5 (group × condition) repeated measures ANOVAs were used to determine significant effects of group and condition on variables of interest.

RESULTS

USA exhibited smaller ApEn values than SSA in the AP signals while no significant differences were observed in the ML CoP signals. Generally, the negative feedback conditions were associated with significantly greater RMS values than the positive feedback conditions.

CONCLUSION

USA exhibit unique postural strategies compared to SSA. These unique strategies seemingly exhibit a direction-specific attribute and may be associated with divergent motor control strategies.