Reliability of muscular activation patterns and their alterations during incremental handcycling in able-bodied participants

Characterization of muscle oxygenation response in well-trained handcyclists

PURPOSE

 Peripheral responses might be important in handcycling, given the involvement of small muscles compared to other exercise modalities. Therefore, the goal of this study was to compare changes in muscle oxygen saturation (∆SmO2) and deoxyhemoglobin level (∆[HHb]) between different efforts and muscles.

METHODS

 Handcyclists participated in a Wingate, a maximal incremental test and a 20-min time-trial (TT). Oxygen uptake (VO2) as well as ∆SmO2, ∆[HHb], deoxygenation and reoxygenation rates in the triceps brachii (TB), biceps brachii (BB), anterior deltoid (AD) and extensor carpi radialis brevis (ER) were measured.

RESULTS

 ER ∆[HHb]max was 37% greater in the incremental test than in the Wingate (ES = 0.392, P = 0.031). TT mean power (W/kg) was associated with BB ∆SmO2min measured in the incremental test (r = -0.998 [-1.190, -0.806], P = 0.002) and in the Wingate (r = -0.994 [-1.327, -0.661], P = 0.006). MAP (W/kg) was associated with Wingate BB ∆SmO2min (r = -0.983 [-0.999, -0.839], P = 0.003), and Wingate peak (r = 0.649 [0.379, 0.895], P = 0.008) and mean power (W/kg) (r = 0.925 [0.752, 0.972], P = 0.003) was associated with right handgrip force. The strongest physiological predictor for TT performance was BB ∆SmO2min in the incremental test (P = 0.002, r2 = 0.993, SEE 0.016 W/kg), Wingate BB ∆SmO2min for MAP (P = 0.003, r2 = 0.956, SEE 0.058 W/kg) and right handgrip force for Wingate peak power (P = 0.005, r2 = 0.856, SEE 0.551 W/kg).

CONCLUSION

 Peripheral aerobic responses (muscle oxygenation) were predictive of handcycling performance.

Association between upper-limb isometric strength and handcycling performance in elite athletes

This study investigated the association among isometric upper-limb strength of handcyclists and sport-specific performance outcomes. At two international events, 62 athletes were tested on upper-limb strength, measured with an isometric-strength setup and with Manual Muscle Test (MMT). Horizontal force (Fz), effectiveness, rate of development, variability, and asymmetries were calculated for upper-limb pull and push. Performance measures were mean (POmean) and peak (POpeak) 20-s sprint power output and average time-trial velocity (TTvelocity). Regression models were conducted to investigate which pull and push strength variables associated strongest with performance measures. Additional regression analyses were conducted with an MMT sum score as predictor. Push and pull Fz showed the strongest associations with all outcomes. Combined push and pull Fz explained (p < .001) 80-81% of variance of POmean and POpeak. For TTvelocity, only push Fz was included in the model explaining 29% of the variance (p < .001). MMT models revealed weaker associations with sprint PO (R2 = .38-.40, p < .001) and TTvelocity (R2 = .18, p = 0.001). The findings confirmed the relevance of upper-limb strength on handcycling performance and the significance of ratio-scaled strength measures. Isometric strength outcomes are adequate sport-specific indicators of impairment in handcycling classification, but future research should corroborate this notion and its potential to discriminate between sports classes.

Effects of 7-week Resistance Training on Handcycle Performance in Able-bodied Males

The effect of an upper body resistance training program on maximal and submaximal handcycling performance in able-bodied males was explored. Eighteen able-bodied men were randomly assigned to a training group (TG: n=10) and a control group (CG: n=8). TG received 7 weeks of upper body resistance training (60% of 1 repetition maximum (1RM), 3×10 repetitions, 6 exercise stations, 2 times per week). CG received no training. Peak values for oxygen uptake (V˙O_2peak), power output (PO_peak), heart rate (HR_peak), minute ventilation (V˙O_Epeak) and respiratory exchange ratio (RER_peak), submaximal values (HR, V˙O₂, RER, PO, and gross mechanical efficiency (GE)), and time to exhaustion (TTE) were determined in an incremental test pre- and post-training. Maximal isokinetic arm strength and 1RM tests were conducted. Ratings of perceived exertion (RPE) were assessed. A two-way repeated measures ANOVA and post-hoc comparisons were performed to examine the effect of time, group and its interaction (p<0.05). TG improved on PO_peak (8.55%), TTE (10.73%), and 1RM (12.28-38.98%). RPE at the same stage during pre- and post-test was lower during the post-test (8.17%). Despite no improvements in V˙O_2peak, training improved PO_peak, muscular strength, and TTE. Upper body resistance training has the potential to improve handcycling performance.

A Role for Trunk Function in Elite Recumbent Handcycling Performance?

Handcycling classification considers trunk function, but there is limited scientific evidence of trunk involvement in recumbent performance. This study investigated the association between trunk function and recumbent handcycling performance of athletes without upper-limb impairments (H3-H4 sport classes). The study was divided into two parts. First, 528 time-trial results from 81 handcyclists with spinal cord injury (SCI) were obtained between 2014 and 2020. Average time-trial velocity was used as performance measure and SCI level as trunk function determinant. Multilevel regression analysis was performed to analyse differences in performance among SCI groups while correcting for lesion completeness, sex, and age. Second, in 26 handcyclists, standardised trunk flexion strength was measured with a handheld dynamometer. Peak and mean power-output from a sprint test and time-trial average velocity were used as performance measures. Spearman correlations were conducted to investigate the association between trunk strength and performance. Results showed that the different SCI groups did not exhibit significant differences in performance. Furthermore, trunk flexion strength and performance exhibited non-significant weak to moderate correlations (for time-trial speed: rs = 0.36; p = 0.07). Results of both analyses suggest that trunk flexion strength does not seem to significantly impact recumbent handcycling performance in athletes without upper-limb impairments.

Wearable Sensors in Sports for Persons with Disability: A Systematic Review

The interest and competitiveness in sports for persons with disabilities has increased significantly in the recent years, creating a demand for technological tools supporting practice. Wearable sensors offer non-invasive, portable and overall convenient ways to monitor sports practice. This systematic review aims at providing current evidence on the application of wearable sensors in sports for persons with disability. A search for articles published in English before May 2020 was performed on Scopus, Web-Of-Science, PubMed and EBSCO databases, searching titles, abstracts and keywords with a search string involving terms regarding wearable sensors, sports and disability. After full paper screening, 39 studies were included. Inertial and EMG sensors were the most commonly adopted wearable technologies, while wheelchair sports were the most investigated. Four main target applications of wearable sensors relevant to sports for people with disability were identified and discussed: athlete classification, injury prevention, performance characterization for training optimization and equipment customization. The collected evidence provides an overview on the application of wearable sensors in sports for persons with disability, providing useful indication for researchers, coaches and trainers. Several gaps in the different target applications are highlighted altogether with recommendation on future directions.

Sport Biomechanics Applications Using Inertial, Force, and EMG Sensors: A Literature Overview

In the last few decades, a number of technological developments have advanced the spread of wearable sensors for the assessment of human motion. These sensors have been also developed to assess athletes' performance, providing useful guidelines for coaching, as well as for injury prevention. The data from these sensors provides key performance outcomes as well as more detailed kinematic, kinetic, and electromyographic data that provides insight into how the performance was obtained. From this perspective, inertial sensors, force sensors, and electromyography appear to be the most appropriate wearable sensors to use. Several studies were conducted to verify the feasibility of using wearable sensors for sport applications by using both commercially available and customized sensors. The present study seeks to provide an overview of sport biomechanics applications found from recent literature using wearable sensors, highlighting some information related to the used sensors and analysis methods. From the literature review results, it appears that inertial sensors are the most widespread sensors for assessing athletes' performance; however, there still exist applications for force sensors and electromyography in this context. The main sport assessed in the studies was running, even though the range of sports examined was quite high. The provided overview can be useful for researchers, athletes, and coaches to understand the technologies currently available for sport performance assessment.

Biomechanics of all-out handcycling exercise: kinetics, kinematics and muscular activity of a 15-s sprint test in able-bodied participants

This study aims to quantify the kinematics, kinetics and muscular activity of all-out handcycling exercise and examine their alterations during the course of a 15-s sprint test. Twelve able-bodied competitive triathletes performed a 15-s all-out sprint test in a recumbent racing handcycle that was attached to an ergometer. During the sprint test, tangential crank kinetics, 3D joint kinematics and muscular activity of 10 muscles of the upper extremity and trunk were examined using a power metre, motion capturing and surface electromyography (sEMG), respectively. Parameters were compared between revolution one (R1), revolution two (R2), the average of revolution 3 to 13 (R3) and the average of the remaining revolutions (R4). Shoulder abduction and internal-rotation increased, whereas maximal shoulder retroversion decreased during the sprint. Except for the wrist angles, angular velocity increased for every joint of the upper extremity. Several muscles demonstrated an increase in muscular activation, an earlier onset of muscular activation in crank cycle and an increased range of activation. During the course of a 15-s all-out sprint test in handcycling, the shoulder muscles and the muscles associated to the push phase demonstrate indications for short-duration fatigue. These findings are helpful to prevent injuries and improve performance in all-out handcycling.

Maximal lactate accumulation rate and post-exercise lactate kinetics in handcycling and cycling

The aim of this study was to assess lactate kinetics, maximal lactate accumulation rate (⩒La_max) and peak power output (PO_max) in a 15-s all-out exercise in handcycling (HC) and cycling (C) in terms of (1) reliability, (2) differences and (3) correlations between HC and C. Eighteen female and male competitive triathletes performed two trials (separated by one week) of a 15-s all-out sprint test in HC and C. Tests were performed in a recumbent racing handcycle and on the participants' own road bike that were attached to an ergometer. Reliability was assessed using intraclass correlation coefficient (ICC). PO_max and ⩒La_max demonstrated high reliability in HC (ICC = 0.972, ICC = 0.828) and C (ICC = 0.937, ICC = 0.872). PO_max (d = -2.54, P < 0.0005) and ⩒La_max (d = -1.62, P < 0.0005) were lower in HC compared to C. PO_max and ⩒La_max correlated in HC (r = 0.729, P = 0.001) and C (r = 0.710, P = 0.001). There was no significant correlation between HC and C in PO_max (r = 0.442, P = 0.066) and ⩒La_max (r = 0.455, P = 0.058). Whereas the exchange velocity of lactate (k₁) was similar in HC and C, the removal velocity (k₂) was significantly higher in HC. ⩒La_max and PO_max during sprint exercise are highly reliable and demonstrate a correlation in both HC and C. However, since ⩒La_max and PO_max are significantly higher in C and not correlated between HC and C, ⩒La_max and PO_max seem to be extremity-specific.

Normalising surface EMG of ten upper-extremity muscles in handcycling: Manual resistance vs. sport-specific MVICs

Muscular activity in terms of surface electromyography (sEMG) is usually normalised to maximal voluntary isometric contractions (MVICs). This study aims to compare two different MVIC-modes in handcycling and examine the effect of moving average window-size. Twelve able-bodied male competitive triathletes performed ten MVICs against manual resistance and four sport-specific trials against fixed cranks. sEMG of ten muscles [M. trapezius (TD); M. pectoralis major (PM); M. deltoideus, Pars clavicularis (DA); M. deltoideus, Pars spinalis (DP); M. biceps brachii (BB); M. triceps brachii (TB); forearm flexors (FC); forearm extensors (EC); M. latissimus dorsi (LD) and M. rectus abdominis (RA)] was recorded and filtered using moving average window-sizes of 150, 200, 250 and 300 ms. Sport-specific MVICs were higher compared to manual resistance for TB, DA, DP and LD, whereas FC, TD, BB and RA demonstrated lower values. PM and EC demonstrated no significant difference between MVIC-modes. Moving average window-size had no effect on MVIC outcomes. MVIC-mode should be taken into account when normalised sEMG data are illustrated in handcycling. Sport-specific MVICs seem to be suitable for some muscles (TB, DA, DP and LD), but should be augmented by MVICs against manual/mechanical resistance for FC, TD, BB and RA.