How to activate the glutes best? Peak muscle activity of acceleration-specific pre-activation and traditional strength training exercises.

PURPOSE: Isometric training and pre-activation are proven to enhance acceleration performance. However, traditional strength training exercises do not mirror the acceleration-specific activation patterns of the gluteal muscles, characterized by ipsilateral hip extension during contralateral hip flexion. Therefore, the aim of the study was to determine gluteal muscle activity of acceleration-specific exercises compared to traditional strength training exercises. METHODS: In a cross-sectional study design, the peak electromyographic activity of two acceleration-specific exercises was investigated and compared to two traditional strength training exercises each for the gluteus maximus and medius. Twenty-four participants from various athletic backgrounds (13 males, 11 females, 26 years, 178 cm, 77 kg) performed four gluteus maximus [half-kneeling glute squeeze (HKGS), resisted knee split (RKS), hip thrust (HT), split squat (SS)] and four gluteus medius [resisted prone hip abduction (RPHA), isometric clam (IC), side-plank with leg abduction (SP), resisted side-stepping (RSS)] exercises in a randomized order. RESULTS: The RKS (p = 0.011, d = 0.96) and the HKGS (p = 0.064, d = 0.68) elicited higher peak gluteus maximus activity than the SS with large and moderate effects, respectively. No significant differences (p > 0.05) were found between the HT, RKS and HKGS. The RPHA elicited significantly higher gluteus medius activity with a large effect compared to RSS (p < 0.001, d = 1.41) and a moderate effect relative to the SP (p = 0.002, d = 0.78). CONCLUSION: The acceleration-specific exercises effectively activate the gluteal muscles for pre-activation and strength training purposes and might help improve horizontal acceleration due to their direct coordinative transfer.

Case Report: Training Monitoring and Performance Development of a Triathlete With Spinal Cord Injury and Chronic Myeloid Leukemia During a Paralympic Cycle.

Introduction: Paratriathlon allows competition for athletes with various physical impairments. The wheelchair category stands out from other paratriathlon categories, since competing in swimming, handcycling, and wheelchair racing entails substantial demands on the upper extremity. Therefore, knowledge about exercise testing and training is needed to improve performance and avoid overuse injuries. We described the training monitoring and performance development throughout a Paralympic cycle of an elite triathlete with spinal cord injury (SCI) and a recent diagnosis of chronic myeloid leukemia (CML). Case Presentation/Methods: A 30-year-old wheelchair athlete with 10-years experience in wheelchair basketball contacted us for guidance regarding testing and training in paratriathlon. Laboratory and field tests were modified from protocols used for testing non-disabled athletes to examine their physical abilities. In handcycling, incremental tests were used to monitor performance development by means of lactate threshold (P OBLA) and define heart rate-based training zones. All-out sprint tests were applied to calculate maximal lactate accumulation rate ( V ˙ La max ) as a measure of glycolytic capabilities in all disciplines. From 2017 to 2020, training was monitored to quantify training load (TL) and training intensity distribution (TID). Results: From 2016 to 2019, the athlete was ranked within the top ten at the European and World Championships. From 2017 to 2019, annual TL increased from 414 to 604 h and demonstrated a shift in TID from 77-17-6% to 88-8-4%. In this period, P OBLA increased from 101 to 158 W and V ˙ La max decreased from 0.56 to 0.36 mmol·l-1·s-1. TL was highest during training camps. In 2020, after he received his CML diagnosis, TL, TID, and P OBLA were 317 h, 94-5-1%, and 108 W, respectively. Discussion: TL and TID demonstrated similar values when compared with previous studies in para-swimming and long-distance paratriathlon, respectively. In contrast, relative TL during training camps exceeded those described in the literature and was accompanied by physical stress. Increased volumes at low intensity are assumed to increase P OBLA and decrease V ˙ La max over time. CML treatment and side effects drastically decreased TL, intensity, and performance, which ultimately hindered a qualification for Tokyo 2020/21. In conclusion, there is a need for careful training prescription and monitoring in wheelchair triathletes to improve performance and avoid non-functional overreaching.

The Science of Handcycling: A Narrative Review.

The aim of this narrative review is to provide insight as to the history, biomechanics, and physiological characteristics of competitive handcycling. Furthermore, based upon the limited evidence available, this paper aims to provide practical training suggestions by which to develop competitive handcycling performance. Handbike configuration, individual physiological characteristics, and training history all play a significant role in determining competitive handcycling performance. Optimal handcycling technique is highly dependent upon handbike configuration. As such, seat positioning, crank height, crank fore-aft position, crank length, and handgrip position must all be individually configured. In regard to physiological determinants, power output at a fixed blood lactate concentration of 4 mmol·L-1, relative oxygen consumption, peak aerobic power output, relative upper body strength, and maximal anaerobic power output have all been demonstrated to impact upon handcycling performance capabilities. Therefore, it is suggested that that an emphasis be placed upon the development and frequent monitoring of these parameters. Finally, linked to handcycling training, it is suggested that handcyclists should consider adopting a concurrent strength and endurance training approach, based upon a block periodization model that employs a mixture of endurance, threshold, interval, and strength training sessions. Despite our findings, it is clear that several gaps in our scientific knowledge of handcycling remain and that further research is necessary in order to improve our understanding of factors that determine optimal performance of competitive handcyclists. Finally, further longitudinal research is required across all classifications to study the effects of different training programs upon handcycling performance.

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.

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

The aim of this study was to assess muscle activity patterns (MAPs) in handcycling in terms of reliability and their alterations due to increasing workload. A total of 12 able-bodied triathletes performed an incremental step test until subjective exhaustion in a racing handcycle that was mounted on an ergometer. During the test, muscular activity of 10 muscles of the upper extremity and trunk was measured using surface electromyography (sEMG). MAPs were examined by calculating integrated EMG (iEMG), the onset, offset and range of activation (RoA). Parameters of MAPs were analysed using intraclass correlation coefficient (ICC) and two-way ANOVA with repeated measures. ICCs ranged from 0.775 to 0.999 indicating 'good' to 'excellent' reliability. All muscles increased their iEMG from low to high intensity with differing effect-sizes. Several muscles showed an earlier onset and increased RoA. MAPs in handcycling are highly reliable and alterated due to increasing workload in able-bodied participants. Whereas muscular effort can be examined in a single cycle, muscle activation characteristics require at least six to ten consecutive revolutions to achieve 'good' or 'excellent' reliability. At high intensity, many muscles demonstrated an earlier onset and larger RoA. Future studies should validate these findings in several elite handcyclists and investigate all-out sprint exercises.

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 (⩒Lamax) and peak power output (POmax) 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). POmax and ⩒Lamax demonstrated high reliability in HC (ICC = 0.972, ICC = 0.828) and C (ICC = 0.937, ICC = 0.872). POmax (d = -2.54, P < 0.0005) and ⩒Lamax (d = -1.62, P < 0.0005) were lower in HC compared to C. POmax and ⩒Lamax 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 POmax (r = 0.442, P = 0.066) and ⩒Lamax (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. ⩒Lamax and POmax during sprint exercise are highly reliable and demonstrate a correlation in both HC and C. However, since ⩒Lamax and POmax are significantly higher in C and not correlated between HC and C, ⩒Lamax and POmax seem to be extremity-specific.

Biomechanics of handcycling propulsion in a 30-min continuous load test at lactate threshold: Kinetics, kinematics, and muscular activity in able-bodied participants.

PURPOSE: This study aims to investigate the biomechanics of handcycling during a continuous load trial (CLT) to assess the mechanisms underlying fatigue in upper body exercise. METHODS: Twelve able-bodied triathletes performed a 30-min CLT at a power output corresponding to lactate threshold in a racing recumbent handcycle mounted on a stationary ergometer. During the CLT, ratings of perceived exertion (RPE), tangential crank kinetics, 3D joint kinematics, and muscular activity of ten muscles of the upper extremity and trunk were examined using motion capturing and surface electromyography. RESULTS: During the CLT, spontaneously chosen cadence and RPE increased, whereas crank torque decreased. Rotational work was higher during the pull phase. Peripheral RPE was higher compared to central RPE. Joint range of motion decreased for elbow-flexion and radial-duction. Integrated EMG (iEMG) increased in the forearm flexors, forearm extensors, and M. deltoideus (Pars spinalis). An earlier onset of activation was found for M. deltoideus (Pars clavicularis), M. pectoralis major, M. rectus abdominis, M. biceps brachii, and the forearm flexors. CONCLUSION: Fatigue-related alterations seem to apply analogously in handcycling and cycling. The most distal muscles are responsible for force transmission on the cranks and might thus suffer most from neuromuscular fatigue. The findings indicate that peripheral fatigue (at similar lactate values) is higher in handcycling compared to leg cycling, at least for inexperienced participants. An increase in cadence might delay peripheral fatigue by a reduced vascular occlusion. We assume that the gap between peripheral and central fatigue can be reduced by sport-specific endurance training.

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.

Evaluation of a sport-specific field test to determine maximal lactate accumulation rate and sprint performance parameters in running.

OBJECTIVES: The aim of this study was to examine the reliability of maximal lactate accumulation rate (V˙Lamax) and sprint performance parameters in running and assess different approaches to determine alactic time interval (talac). DESIGN: Sixteen competitive runners (female=5; male=11) performed three trials (T1, T2 and T3) of an all-out 100-m sprint test separated by 48h. METHODS: Time to cover the 100m was determined by using a photoelectric light-barrier (t100,LB) and a stop-watch (t100,SW). Throughout the sprints, velocity was measured using a laser velocity guard (LAVEG) to estimate maximal velocity (vmax) and power (Pmax). The talac was calculated as the time when power decreased by 3.5% (tpmax-3.5%) and interpolated based on the sprint time (tinter,LB and tinter,SW). Reliability was assessed using intraclass correlation coefficient (ICC), typical error (TE) and smallest worthwhile change (SWC). RESULTS: After initial familiarisation, t100, tinter, vmax, Pmax and V˙Lamax attained excellent reliability (ICC≥0.90), whereas tpmax-3.5% attained moderate reliability (ICC=0.518). The reliability of V˙Lamax was higher when tinter,LB or tinter,SW were used (ICC=0.960) compared to using tpmax-3.5% (ICC=0.928). At T1, V˙Lamax was significantly higher when stop-watch measurements were used. There was no difference between tpmax-3.5% and the interpolated time intervals and the associated V˙Lamax-estimates. CONCLUSIONS: In running, V˙Lamax and sprint performance parameters can easily and high-reliably be measured using this sport-specific field test. Interpolating talac results in similar and more reliable values of V˙Lamax. To improve the reliability and accuracy of the stop-watch estimate, a familiarisation should be performed.

Lactate kinetics in handcycling under various exercise modalities and their relationship to performance measures in able-bodied participants.

PURPOSE: The aim of this study was to expand exercise testing in handcycling by (1) examining different approaches to determine lactate kinetics in handcycling under various exercise modalities and (2) identifying relationships between parameters of lactate kinetics and selected performance measures. METHODS: Twelve able-bodied nationally competitive triathletes performed a familiarisation, a sprint test, an incremental step test, and a continuous load trial at a power output corresponding to a lactate concentration (La) of 4 mmol l-1 (PO4) in a racing handcycle that was mounted on an ergometer. During the tests, La and heart rate (HR) were determined. As performance measures, maximal power output during the 15-s All-Out sprint test (POmax,AO15) and maximal power output during the incremental test (POmax,ST) were determined. As physiological parameters, coefficients of lactate kinetics, maximal lactate accumulation rate ([Formula: see text]Lamax), maximal La following the sprint test and incremental test (Lamax,AO15, Lamax,ST) and the increase in La within the last 20 min of the continuous trial (LaCrit,CT) were determined. RESULTS: Mean values of POmax,AO15 (545.6 ± 69.9 W), POmax,ST (131.3 ± 14.9 W), PO4 (86.73 ± 12.32 W), [Formula: see text]Lamax (0.45 ± 0.11 mmol l-1 s-1), Lamax,AO15 (6.64 ± 1.32 mmol l-1), Lamax,ST (9.64 ± 2.24 mmol l-1) and LaCrit,CT (0.74 ± 0.74 mmol l-1) were in accordance to literature. [Formula: see text]Lamax was positively correlated with Lamax,AO15 and POmax,AO15 and negatively correlated with POmax,ST. POmax,ST was negatively correlated with Lamax,AO15. PO4 was negatively correlated with Lamax,ST. CONCLUSIONS: [Formula: see text]Lamax was identified as a promising parameter for exercise testing in handcycling that can be supplemented by other parameters describing lactate kinetics following a sprint test.