Hypoalgesic Effects of Aerobic and Isometric Motor Imagery and Action Observation Exercises on Asymptomatic Participants: A Randomized Controlled Pilot Trial

EVALUATION OF DIFFICULTY IN WOMEN’S AEROBIC GYMNASTICS COMPETITIONS

ABSTRACT Introduction Feminine aerobic gymnastics is a highly artistic competition, and analyzing its difficulties is fundamental. Objective This work analyzes the difficulty of the movements of feminine aerobic gymnastics. This study aims to explore the choreographic characteristics of the difficulty of the movements and evaluate their difficulties. Methods Several female aerobics athletes are selected as volunteers for the research. The women’s aerobic gymnastics video points are classified, grouped, scored, and their actions combined, recorded, and organized. Mathematical statistics are used to analyze the difficulty of aerobics movements. Results The difficulty factor is the best quantitative scoring criterion to judge the competition results. The highest frequency in Group B was the right-angle split leg combination to support the 720° twist. The highest frequency in Group C was the 180° scissor transformation. The highest frequency in Group D was the unsupported vertical split. The five-person project difficulty score choice tended to be stable and high. Conclusion The transition types of difficulty action space in the competition of the women’s aerobics team are B-C-B, B-C-A, B, A. The difficulty score of the women’s aerobics team competition was significantly correlated with the final score. Level of evidence II; Therapeutic studies - investigating treatment outcomes.

Effects of Self-Efficacy and Outcome Expectations on Motor Imagery-Induced Thermal and Mechanical Hypoalgesia: A Single-Blind Randomised Controlled Trial

The main aim of this study was to assess whether self-efficacy (SE) and outcome expectations (OEs) modulate the hypoalgesic effect induced by motor imagery (MI). A total of 75 asymptomatic participants were randomly assigned to the positive (SE+, OE+), negative (SE-, OE-) or non-expectation (CG) groups. Heat pain threshold (HPT) and pain pressure threshold (PPT) were the main variables. Cold detection threshold (CDT), warm detection threshold (WDT), heart rate (HR) and perceived fatigue were the secondary variables. The variables were assessed preintervention, immediately postintervention and 10 min postintervention, except for HR, which was measured continuously during the intervention. Regarding HPT, significant within-group pre-post differences were found in the OE+ group, with a low effect size (p = 0.01, d = -0.39). With regard to ΔPPT, significant intergroup differences were found in Δpost-pre between the SE+ and CG groups (p = 0.012, d = 1.04) and also between SE+ and OE- (p = 0.006, d = 1.08), both with a large effect size. CG, SE-, and OE- groups had poorer CDT and WDT. Regarding HR, significant intergroup differences were found in the postintervention measurement between OE+ and SE-, with a large effect size (p = 0.016, d = 1.34). Lastly, no between-group differences were found regarding perceived fatigue (p > 0.05). The results obtained showed that positive expectations have a slight influence on the increase in heat and mechanical pain detection thresholds. Positive and non-expectancy groups showed an autonomic activation. The results also showed that negative expectations led to poorer perceptual processes.

Effects of Exercise-induced Hypoalgesia and Its Neural Mechanisms

PURPOSE

Exercise-induced hypoalgesia is frequently documented in the literature. However, the underlying neural mechanism of this phenomenon remains unclear. Here, we explored the effects of different intensities of isometric exercise on pain perception with a randomized controlled design and investigated its neural mechanisms through tracing the dynamic changes of heat-evoked brain responses.

METHODS

Forty-eight participants were randomly assigned to one of the three groups with different exercise intensities (i.e., high, low, and control). Their subjective pain reports and brain responses elicited by heat stimuli before and after exercise were assessed.

RESULTS

We observed 1) the increased pressure pain thresholds and heat pain thresholds on the dorsal surface of the hand and the biceps brachii muscle of the exercised limb (closed to the contracting muscle), and the decreased pressure pain ratings at the indexed finger of the unexercised limb; 2) more reduction of pain sensitivity on both the biceps brachii muscle and the dorsal surface of the hand induced by the high-intensity isometric exercise than the low-intensity isometric exercise; and 3) both the high-intensity and the low-intensity isometric exercise induced the reduction of N2 amplitudes and N2-P2 peak-to-peak amplitudes, as well as the reduction of event-related potential magnitudes elicited by the heat stimuli on the exercised limb.

CONCLUSIONS

The hypoalgesic effects induced by the isometric exercise were not only localized to the moving part of the body but also can be extended to the distal part of the body. The exercise intensities play a vital role in modulating these effects. Exercise-induced hypoalgesia could be related to the modulation of nociceptive information transmission via a spinal gating mechanism and also rely on a top-down descending pain inhibitory mechanism.