Postural Balance Following Aerobic Fatigue Tests: A Longitudinal Study Among Young Athletes

Temporal adaptation of the postural control following a prolonged fin swimming

PURPOSE

Postural control deteriorates following a transition between two environments, highlighting a sensory conflict when returning to natural conditions. Aquatic immersion offers new perspectives for studying postural control adaptation in transitional situations. Our aim is to study immediate and post-task static postural control adaptation on land after a prolonged fin swimming exercise in total immersion.

METHODS

Standing static postural control was assessed in 14 professional or recreational SCUBA divers (11 men, 3 women; 33.21 ± 10.70 years), with eyes open and closed, before, immediately after, and in the following 20 min following a fully-immersed 45-min fin swimming exercise. Centre-of-pressure metrics (COP) including average position, amplitude, velocity, length and 95% ellipse were evaluated in medial-lateral (x-axis) and anterior-posterior (y-axis) directions with a force platform. The Romberg ratio was also assessed for each metric.

RESULTS

A two-way repeated measures analysis of variance revealed a significant effect of the measurement period on COPx vel (p = 0.01), COPy vel (p < 0.01) and Length (p < 0.01), and of the visual condition on COPy vel (p < 0.01) and Length (p < 0.01). Eyes closed measures were systematically higher than eyes open measures despite there being no significant difference in the Romberg ratio in all periods. Post-immersion, the velocity and total trajectory of the centre of pressure remained systematically lower than baseline values in both visual conditions.

CONCLUSION

Post-immersion, COP velocity and length significantly decreased, suggesting a sensory reweighting strategy potentially associated with ankle stiffening.

Exploring how arm movement moderates the effect of lower limb muscle fatigue on dynamic balance in healthy youth

Background

In young adults, there is evidence that free arm movements do not help to compensate muscle fatigue-induced deteriorations in dynamic balance performance. However, the postural control system in youth is immature, and as a result, the use of arm movements may provide a compensatory "upper body strategy" to correct fatigue-related balance impairments. Thus, the purpose of the present study was to compare the effects of free vs. restricted arm movement on dynamic balance performance prior and following exercise-induced muscle fatigue.

Methods

Forty-three healthy youth (19 females; mean age: 12.8 ± 1.9 years) performed the Y Balance Test-Lower Quarter before and immediately after a fatiguing exercise (i.e., repetitive vertical bipedal box jumps until failure) using two different arm positions: free (move the arms freely) and restricted (keep the arms akimbo) arm movement.

Results

Muscle fatigue (p ≤ 0.033; 0.10 ≤ η p 2 ≤ 0.33) and restriction of arm movement (p ≤ 0.005; 0.17 ≤ η p 2 ≤ 0.46) resulted in significantly deteriorated dynamic balance performance. However, the interactions between the two did not reach the level of significance (p ≥ 0.091; 0.01 ≤ η p 2 ≤ 0.07).

Conclusion

Our findings indicate that the use of an "upper body strategy" (i.e., free arm position) has no compensatory effect on muscle fatigue-induced dynamic balance deteriorations in healthy youth.

The Function of the Proprioceptive, Vestibular and Visual Systems Following Fatigue in Individuals With and Without Chronic Ankle Instability

To maintain postural balance, the proprioceptive, vestibular, and visual systems continuously provide body position and movement data to the central nervous system. In this study, our main aim was to examine, for the first time, the influence of anaerobically or aerobically induced fatigue on these separate functions in persons with and without chronic ankle instability (CAI). We obtained assessments pre- and post-fatigue protocols from 60 physical education students (Mage = 24.3, SD = 3.4) Twenty-seven students had CAI, and 33 students did not have CAI). To measure proprioception, we used the AMEDA device; for vision, we used near point of convergence (NPC); and, for vestibular function, we used subjective visual vertical (SVV). We found a pre-post proprioception (AMEDA) effect in the aerobic group (p < .001), and a visual (NPC) effect in both anaerobic and aerobic participant groups (both p < .001). There were no visual system (NPC) fatigue effect differences among aerobic or anerobic participants who had or did not have CAI (p = .047); there was a significant aerobic fatigue effect on proprioception (AMEDA) (p = .010) that favored participants without CAI. There was a significant interaction effect between time of testing and CAI for visual (NPC) (p = .003) in the aerobic group only. In both the anaerobic and aerobic groups, post-fatigue vestibular function (AMEDA) was significantly lower for those with than those without CAI (anaerobic: p = .030; and aerobic: p =.016). Thus, post-fatigue, participants with CAI showed worse proprioceptive, visual, and vestibular function than those without CAI. Future investigators should further examine each movement sense system in individuals with CAI.

Another Look at Fatigued Individuals with and without Chronic Ankle Instability: Posturography and Proprioception

Fatigue can impair function of the three sensory systems (vestibular, visual, and somatosensory) that control postural balance. Yet impairment may be greater among individuals with than those without chronic ankle instability (CAI). The present study used posturography assessment to extend previous findings demonstrating reduced function of the three systems in CAI participants following fatigue. Our aim in this study was to examine the influence of anaerobic and aerobic protocols on the function of these three sensory systems in individuals with and without CAI. We assessed 60 healthy physical education students (Mage = 24.3, SD = 3.4) by a Tetrax® Posturography device for Stability-Index and Fourier-frequencies [low sway (F1) visual input, medium-low sway (F2-F4) vestibular input, medium-high sway (F5-F6) somatosensory input] and by the Active Movement Extent Discrimination Assessment (AMEDA) for active ankle somatosensory ability, before and after performing anaerobic or aerobic protocols. Among participants, 45% were identified with CAI. We found significant Time effect (pre-post), CAI effect, and CAI X Time interactions for Fourier frequencies, Stability-Index, and AMEDA scores, indicating greater pre-post deterioration for those with CAI compared to those without CAI (p < .05). CI (95%) showed that, although there was a Time effect for F1, F2-F4, and F5-F6, only F5-F6 frequencies (i.e., somatosensory input) showed the CAI effect and the Time X CAI interaction. Thus, participants with and without CAI showed reduced visual, vestibular, and somatosensory ability following fatigue. While we found greater deterioration in both passive and active somatosensory ability (F5-6 and AMEDA) among individuals with CAI compared with those with no-CAI, we recommend intervention programs for improving vestibular abilities following fatigue in both those with and without CAI.

Effects of Aerobic and Anaerobic Fatigue Exercises on Postural Control and Recovery Time in Female Soccer Players

Sixteen female soccer players (age = 20.19 ± 1.52 years; body mass = 56.52 ± 4.95 kg; body height = 164.81 ± 4.21 cm) with no history of lower extremity injury participated in the study. The Biodex SD Balance system was used to determine the non-dominant single-leg stability. In anaerobic exercise, each subject performed four maximal cycling efforts against a resistance equivalent to 0.075 kg/body mass for 30 s with three-minute rest intervals. In aerobic exercise, subjects performed the Bruce protocol on a motorized treadmill. After each exercise, subjects subsequently performed a single-leg stability test and then repeated the same test for four times with five-minute passive rest periods. In accordance with the results, it was found that the impairment observed right after the aerobic loading was higher (p < 0.001) compared to the anaerobic one. However, the time-related deterioration in both aerobic and anaerobic loadings was similar. The B-pre value was lower than B_post and B₅ (p < 0.01) and B₁₀ (p < 0.05) in both conditions. Subjects could reach the initial balance level at B₁₅ after aerobic and anaerobic loadings. The lactate level did not reach resting value even after 20 min of both fatigue protocols. Although the fatigue after aerobic and aerobic exercise negatively affects a single-leg dynamic balance level, single leg balance ability returns to the baseline status after 10 min of passive recovery duration.

Evaluation of Visual Field and Balance Function Alterations in Patients Who Underwent Dermatochalasis Surgery

Purpose

To compare perioperative visual field (VF), balance functions (BF), and changes in the other ocular parameters in patients undergoing upper eyelid dermatochalasis (DC) surgery.

Methods

One hundred and fifty-eight eyes of 79 patients who underwent DC surgery were included in the study. The VF, BF, intraocular pressure (IOP), pachymetry (PM), macular, and optic nerve measurements were recorded. Measurements were repeated at postoperative month 1. The preoperative and postoperative ocular measurements and the balance data were compared.

Results

Nineteen of 79 (24.05%) patients were male and 60 of 79 (75.95%) were female, while the mean age of the patients was 58.65 ± 7.38 years. There were statistically significant differences in terms of VF and macular thickness between the preoperative and postoperative values. The improvements in mean defect, standard loss variance, and mean sensitivity values of global VF parameters in both eyes were statistically significant after surgery. Central macular thickness, mean macular thickness, and macular volume decreased significantly in all eyes after surgery (p < 0.05).

Conclusions

Although a marked improvement was observed in VF and peripheral vision after surgery, no significant change was found in BF parameters including primarily falling risk. The significant change in the macular parameters was only remarkable, and we think that the decrease was due to subtle vasospasm. There is a need for further comprehensive studies including especially patients older than 65 with a view to understanding the effect of DC surgery on BF.

A balance and proprioception intervention programme to enhance combat performance in military personnel

BACKGROUND

Optimal functioning of the lower extremities under repeated movements on unstable surfaces is essential for military effectiveness. Intervention training to promote proprioceptive ability should be considered in order to limit the risk for musculoskeletal injuries. The aim of this study was to assess the effect of a proprioceptive intervention programme on static and dynamic postural balance among Israel Defense Forces combat soldiers.

METHODS

Twenty-seven male soldiers, aged 18-20 years, from a physical fitness instructor's course, were randomly divided into two groups matched by age and army unit. The intervention group (INT) underwent 4 weeks of proprioceptive exercises for 10 min daily; the control group underwent 4 weeks of upper body stretching exercises for 10 min daily. All participants were tested pre and postintervention for both static and dynamic postural balance.

RESULTS

Significant interaction (condition*pre-post-test*group) was found for static postural balance, indicating that for the INT group, in condition 3 (on an unstable surface-BOSU), the post-test result was significantly better compared with the pretest result (p<0.05). Following intervention, the INT group showed significant correlations between static postural stability in condition 2 (eyes closed) and the dynamic postural stability (length of time walked on the beam following fatigue) (r ranged from 0.647 to 0.822; p<0.05).

CONCLUSIONS

The proprioceptive intervention programme for combat soldiers improved static postural balance on unstable surfaces, and improved the correlation between static postural balance in the eyes closed condition and dynamic postural balance following fatigue. Further longitudinal studies are needed to verify the relationship between proprioception programmes, additional weight bearing and the reduction of subsequent injuries in combat soldiers.