Wavelet coherence as a measure of trunk stabilizer muscle activation in wheelchair fencers

Trunk and glenohumeral joint adaptations to manual wheelchair propulsion over a cross-slope: An exploratory study

BACKGROUND

Cross-slopes are often encountered by manual wheelchair users propelling within an urban setting. While propulsion over cross-slopes is more difficult than on level surfaces, little is known about how the users counter the downhill turning tendency of the wheelchair over cross-slopes. This study aimed to identify the adaptations of the manual wheelchair users to the presence of cross-slopes and examine how these might impact shoulder injury.

METHODS

Nine manual wheelchair users propelled themselves across a cross-slope and over a level surface. The trunk and glenohumeral joint kinematics, as well as the handrim contact tangential force were compared between both conditions for the uphill and downhill limbs.

FINDINGS

The uphill arm technique used to counter the downhill turning tendency varied greatly in terms of potential injury risk and efficiency between participants. Trunk flexion increased the turning tendency of the manual wheelchair, yet only one participant decreased his flexion when rolling over the cross-slope. Various potential pathomecanisms related to the trunk lateral flexion and the glenohumeral kinematics over a cross-slope were identified.

INTERPRETATION

Both the uphill arm technique and trunk kinematics are important to propel over a cross-slope both efficiently and safely. Accordingly, tips about posture and kinematics are needed to teach this skill to manual wheelchair users. Additionally, as wheelchair positioning seems to influence the cross-slope skill, more research is needed to explore the impact of positioning devices (e.g., lateral supports) and wheelchair modifications (e.g., power assist wheels, handrim projections) on this skill.

A standard operating procedure for the physical performance analysis of wheelchair fencer: a scoping review

INTRODUCTION

Wheelchair fencing (WF) is a very practiced sport within the Paralympic world. A careful analysis of the characteristics and data of a WF athlete can be useful for coaches and movement experts to better plan a training program. The objective of the study was to evaluate physical fitness assessment methods adopted in WF and to propose a standard operating procedures (SOP).

EVIDENCE ACQUISITION

Original articles written in English were included in this review, and the population studied was composed of athletes who practiced WF. Studies were searched from PubMed, Web of Science, and Scopus databases using keywords and Boolean operators. Eight studies were included in this review.

EVIDENCE SYNTHESIS

Most of the studies converge and agree on the physical, physiological, and technical characteristics of a WF athlete.

CONCLUSIONS

The scientific literature referring to this sport is very scarce, hence the need for new original studies to optimize the SOP proposed.

Correlations between the EMG Structure of Movement Patterns and Activity of Postural Muscles in Able-Bodied and Wheelchair Fencers

The study involved Paralympic wheelchair fencers (N = 7) in two disability categories, and able-bodied female epee fencers (N = 7), members of the polish paralympic fencing teams. The performance of postural muscles and sword arm muscles in both groups of fencers, and of the front and rear leg muscles in the able-bodied fencers, was examined using surface electromyography with an accelerometer and the OptiTrack motion analysis system, as well as ground force reaction platforms. The activation sequence of individual muscles was determined and the structure of movement patterns in able-bodied and wheelchair fencers was formulated. A statistically significant correlation was found between the complex motor reaction time and latissimus dorsi muscle activation (p = 0.039, Z = -2.062) in wheelchair fencers. High correlations between the vertical force and EMG signal values of the gastrocnemius caput laterale muscle (0.85 for p = 0.022) were found in able-bodied fencers. A heuristic analysis indicated the significance of postural muscles in the movement patterns of wheelchair and able-bodied fencers. These muscles play a crucial role in the anticipatory postural adjustment of the trunk during technical fencing actions, including attacks on the opponent's body.

Age-Related Differences in Intermuscular Coherence EMG-EMG of Ankle Joint Antagonist Muscle Activity during Maximal Leaning

BACKGROUND

Intermuscular synchronization is one of the fundamental aspects of maintaining a stable posture and is of great importance in the aging process. This study aimed to assess muscle synchronization and postural stabilizer asymmetry during quiet standing and the limits of stability using wavelet analysis. Intermuscular synchrony and antagonistic sEMG-sEMG (surface electromyography) coherence asymmetry were evaluated in the tibialis anterior and soleus muscles.

METHODS

The study involved 20 elderly (aged 65 ± 3.6) and 20 young (aged 21 ± 1.3) subjects. The task was to perform a maximum forward bend in a standing position. The prone test was divided into three phases: quiet standing (10 s), dynamic learning, and maintenance of maximum leaning (20 s). Wavelet analysis of coherence was performed in the delta and beta bands.

RESULTS

Young subjects modulated interface coherences to a greater extent in the beta band. Analysis of postural stability during standing tasks showed that only the parameter R2b (the distance between the maximal and minimal position central of pressure), as an indicator for assessing the practical limits of stability, was found to be significantly associated with differences in aging.

CONCLUSION

The results showed differences in the beta and delta band oscillations between young and older subjects in a postural task involving standing quietly and leaning forward.

Thermovision as a Tool for Athletes to Verify the Symmetry of Work of Individual Muscle Segments

In the presented research, we characterised the temperature profiles and the degree of preparation for exercise of individual muscle groups of athletes We hypothesise that by means of thermal imaging studies, the effectiveness of the warm-up can be monitored to determine whether the effort of individual muscles is equal and symmetrical, which can help to avoid a potential injury. In the study, thermographic imaging was performed on a group of athletes exercising on a rowing ergometer involving almost 80% of the muscle parts of the human body for intense and symmetrical exercise. Thermovision studies have confirmed, based on the increased temperature of the muscle areas, that the rowing ergometer involves many muscle groups in training. Moreover, based on the shape of the temperature function obtained from individual body regions of interest, it was shown that conventional exercise on a rowing ergometer causes almost symmetrical work of the right and left sides of the body. Obtained temperature changes in most of the studied muscle areas showed minimum temperature reached the beginning of training—mostly phases 1 and 2. During the subsequent phases, the temperature increase was monitored, stopping at resting temperature. Significantly, temperature variations did not exceed 0.5 °C in all post-training phases. Statistical analyses did not show any significant differences in the symmetry of right and left muscle areas corresponding to the muscle location temperature. Thermal imaging may be an innovative wholly non-invasive and safe method, because checking induces adaptation processes, which may become indicators of an athlete’s efficiency. The imaging can be continuously repeated, and automatic comparison of average temperature or temperature difference may provide some clues that protect athletes from overtraining or serious injuries.

Electromyography, Wavelet Analysis and Muscle Co-Activation as Comprehensive Tools of Movement Pattern Assessment for Injury Prevention in Wheelchair Fencing

The aim of the study was to determine the correct movement patterns of fencing techniques in wheelchair fencers. Through a comprehensive analysis, the key muscles in the kinematic chain exposed to potential injuries were identified. The study participants were 16 wheelchair fencers, divided into two groups representing two categories of disability: Group A (N = 7) comprising fencers with mild paraplegia, having freedom of movement of the trunk and arms; and Group B (N = 9) comprising fencers with a spinal cord injury and partial paresis of the arms. EMG and an accelerometer were used as the main research tools. The EMG electrodes were placed on the muscles of the sword arm as well as on the left and right sides of the abdomen and torso. The EMG signal was transformed using wavelet analysis, and the muscle activation time and co-activation index (CI) were determined. In Group A fencers, first the back and abdominal muscles were activated, while in Group B, it was the deltoid muscle. The wavelet coherence analysis revealed intermuscular synchronization at 8–20 Hz for Group A fencers and at 5–15 Hz for Group B fencers. In Group A fencers, the co-activation index was 50.94 for the right-side back and abdominal muscles, 50.75 for the ECR-FCR, and 47.99 for the TRI-BC pairs of upper limb muscles. In contrast, Group B fencers demonstrated higher CI values (50.54) only for the postural left-side muscle pairs. Many overload injuries of the shoulder girdle, elbow, postural muscles, spine, and neck have been found to be preventable through modification of current training programs dominated by specialist exercises. Modern wheelchair fencing training should involve neuromuscular coordination and psychomotor exercises. This will facilitate the individualization of training depending on the fencer’s degree of disability and training experience.