Physical demands of elite rugby league match-play and the subsequent impact on recovery

Whilst fatigue in the days after elite rugby league match-play has been well documented, the specific match actions which contribute to fatigue are not well understood. Thus, the purpose of this study was to examine the relationship between the physical demands of elite rugby league match-play and fatigue in the days after. Twenty-eight individual performances from an English Super League team were captured using a 10 Hz global positioning system (GPS). Upper and lower body neuromuscular fatigue, plasma creatine kinase (CK) and perceptual well-being were assessed 24 h before, immediately after, and at 12, 36 and 60 h after a competitive match. Backs covered more distance during sprinting (214.5 ± 117.6 m) and highintensity sprinting (129.6 ± 110.9 m) than forwards (142.9 ± 86.2 and 57.1 ± 67.6 m, respectively), whereas forwards experienced significantly more collisions than backs (75.1 ± 64.1 cf. 37.6 ± 18.8). CK concentration peaked at 12 h and remained significantly elevated up to 60 h post-match (p < 0.05). Large decrements in countermovement jump (CMJ) and small to moderate decrements in repeated plyometric push-up (RPP) performance were evident at 12 and 36 h post-match. Well-being questionnaire (WQ) score was significantly decreased up to 36 h post-match (p < 0.05), specifically large increases in perceived muscle soreness were found at 12 and 36 h. Duration (r = 0.8), total distance covered (r = 0.79) and efforts performed over 18 km·h-1 (r = 0.78) were strongly associated with CK concentration. High intensity accelerations (r = 0.47) and decelerations (r = 0.45) were significantly associated with CK concentration. Total collisions and repeated high-intensity effort (RHIE) bouts were associated with decrements in RPP (r = -0.49 and r = -0.51, respectively), CK concentration (r = 0.56 and r = 0.63, respectively) and perceived muscle soreness (r = -0.52 and r = -0.48, respectively). The findings suggest duration of match-play, high intensity running and collisions experienced were the strongest predictors of fatigue following elite rugby league match-play

The internal and external demands of multi-directional running and the subsequent effect on side cut biomechanics in male and female team sport athletes

The aim of this thesis was to examine the physiological and biomechanical responses to multi-directional running in male and female team sport athletes. Chapter 4 compared measures of energy expenditure derived from indirect calorimetry and microtechnology, as well as high power and high-speed activity, during linear and multi-directional running. Measured energy expenditure was higher during the multidirectional trial (9.0 ± 2.0 cf. 5.9 ± 1.4 kcal.min-1), whereas estimated energy expenditure was higher during the linear trial (8.7 ± 2.1 cf. 6.5 ± 1.5 kcal.min-1). Whilst measures of energy expenditure were strongly related (r > 0.89, p < 0.001), metabolic power underestimated energy expenditure by 52% (95% LoA: 20-93%) and 34% (95% LoA: 12-59%) during the multi-directional and linear trial, respectively. Time at high power was 41% (95% LoA: 4-92%) greater than time at high speed during the multidirectional trial, whereas time at high power was 5% (95% LoA: -17-9%) lower than time at high speed during the linear trial. Chapter 5 explored the internal and external responses to linear and multi-directional running, specifically examining if measures of high speed and high power reflect changes in internal load. High speed distance (p < 0.001) was higher during the linear trial, whereas time at high power (p = 0.046) and accelerations performed (p < 0.001) were higher during the multi-directional trial. Summated HR (-0.8; ±0.5, p = 0.003), B[La] (-0.9; ±0.6, p = 0.002) and RPE (-0.7; ±0.6, p = 0.024) were higher during the multi-directional trial. There was a large difference in the ratio of high speed:summated HR (1.5; ±0.5, p = 0.001) and high speed:total V̇O2 (2.6; ±1.2, p < 0.001) between linear and multi-directional running, whilst high power:summated HR (0.3; ±0.5, p = 0.246) and high power:total V̇O2 (0.1;±0.8, p = 0.727) were similar. A small decrement in knee flexor torque was observed after the multi-directional (0.4; ±0.4, p = 0.017) and linear (0.2; ±0.3, p = 0.077) trials, respectively. Collectively, Chapters 4 and 5 reveal that more directional changes induce a greater internal response, despite reducing the high-speed distance someone is likely to cover. High power better reflects internal responses to multidirectional running than high speed, but microtechnology cannot be used to determine the absolute energy cost of multi-directional running. Chapters 6 and 7 explored alterations in side cut biomechanics in males and females immediately (Chapter 6) and 48 h (Chapter 7) after multi-directional running. In Chapter 6, 20 m sprint time was higher (ES: 0.65 – 1.17, p < 0.001) after multidirectional running, indicating the presence of fatigue. Males and females displayed trivial to moderate changes in trunk flexion (0.16 – 0.28, p = 0.082), peak hip internal rotation (0.46 – 0.54, p = 0.090), and knee flexion (0.17 – 0.41, p = 0.055) and higher knee abduction (0.40 – 0.51, p = 0.045) and internal rotation (0.59 – 0.81, p = 0.038) angular velocities, during the weight acceptance phase of side cuts after multidirectional running. Peak hip extensor (0.19 – 0.29, p = 0.055) and knee internal rotation moment (0.22 – 0.34, p = 0.052) displayed trivial to small increases after multidirectional running, whereas peak hip external rotation (0.44 – 0.57, p = 0.011), knee extensor (0.33 – 0.45, p = 0.003) moment and knee to hip extensor ratio (0.15 – 0.45, p = 0.005) were lower. In addition, IGRF displayed trivial to moderate changes (0.04 – 0.79, p = 0.066) and lateral GRF was lower (0.29 – 0.85, p = 0.002) after multidirectional running. In Chapter 7, CK concentration (2.4 – 4.94, p = 0.009), perceived muscle soreness (4.2 – 4.8, p < 0.001) and 20 m sprint time (0.6 – 0.9, p < 0.001) were higher 48 h after multi-directional running, indicating the presence of EIMD. Males and females displayed trivial to moderate changes in peak torso flexion (0.13 – 0.35, p = 0.055), hip internal rotation angular velocity (0.43 – 0.64, p = 0.073) and more knee internal rotation (0.31 – 0.5, p = 0.009) 48 h after multi-directional running. A tendency for an interaction between sex and time was noted for peak knee flexion (p = 0.068) and internal rotation angular velocity (p =0.057), with males only displaying a moderate increase. Males and females also displayed a lower peak knee extensor moment (0.43 – 0.56, p = 0.001) and a small increase in extensor moment (0.21 –0.46, p = 0.066) and knee external rotation moment (0.34 – 0.78, p = 0.062). An interaction between sex and time was noted for IGRF (p = 0.037); there was a large increase in IGRF at 48 h in females (1.4) but not males (0.08). For the first time, these data highlight multi-directional running which elicits fatigue and EIMD causes alterations in side cut biomechanics which can persist for at least 48 h. Specifically, both males and females performed side cuts in a more extended position, with higher peak angular velocities, and peak knee external rotation moments and less knee extensor moments both immediately and 48 h after multi-directional running

Energy expenditure, metabolic power and high speed activity during linear and multi-directional running

Objectives: The purpose of the study was to compare measures of energy expenditure derived from indirect calorimetry and micro-technology, as well as high power and high speed activity during linear and multi-directional running. Design: Repeated measures Methods: Twelve university standard team sport players completed a linear and multi-directional running condition. Estimated energy expenditure, as well as time at high speed (> 14.4 km.h-1) and high power (> 20 W.kg-1) were quantified using a 10 Hz micro-technology device and compared with energy expenditure derived from indirect calorimetry. Results: Measured energy expenditure was higher during the multi-directional condition (9.0 ± 2.0 cf. 5.9 ± 1.4 kcal.min-1), whereas estimated energy expenditure was higher during the linear condition (8.7 ± 2.1 cf. 6.5 ± 1.5 kcal.min-1). Whilst measures of energy expenditure were strongly related (r > 0.89, p < 0.001), metabolic power underestimated energy expenditure by 52% (95% LoA: 20-93%) and 34% (95% LoA: 12-59%) during the multi-directional and linear condition, respectively. Time at high power was 41% (95% LoA: 4-92%) greater than time at high speed during the multi-directional condition, whereas time at high power was 5% (95% LoA: -17-9%) lower than time at high speed during the linear condition. Conclusions: Estimated energy expenditure and time at high metabolic power can reflect changes in internal load. However, micro-technology cannot be used to determine the energy cost of intermittent running

The Relationship Between Match-Play Characteristics of Elite Rugby League and Indirect Markers of Muscle Damage

As accepted for publicationPurpose: Whilst exercise-induced muscle damage (EIMD) after a rugby league match has been well documented, the specific match actions that contribute to EIMD are unclear. Accordingly, the purpose of this study was to examine the relationship between the physical demands of elite rugby league matches and subsequent EIMD. Methods: Twenty-eight performances were captured using 10 Hz global positioning systems. Upper and lower body neuromuscular fatigue, creatine kinase (CK) and perceived muscle soreness were assessed 24 h before and at 12, 36 and 60 h after a competitive match. Results: High-intensity running was moderately higher in backs (6.6 ± 2.6 m•min-1) compared to forwards (5.1 ± 1.6 m•min-1), whereas total collisions were moderately lower (31.1 ± 13.1 cf. 54.1 ± 37.0). Duration (r = 0.9, CI: 0.77 to 0.96), total distance covered (r = 0.86, CI: 0.7 to 0.95) and distance covered over 18 km•h-1 (r = 0.76, CI: 0.51 to 0.91) were associated with increased CK concentration post-match. Total collisions and repeated high-intensity efforts (RHIE) were associated with large decrements in upper body neuromuscular performance (r = -0.48, CI: -0.74 to 0.02 and r = -0.49, CI: -0.77 to 0.05, respectively), muscle soreness (r = -0.68, CI: -0.87 to -0.1 and r = -0.66, CI: -0.89 to 0.21, respectively), and CK concentration (r = 0.67, CI: 0.42 to 0.85 and r = 0.73, CI: 0.51 to 0.87, respectively). Conclusion: Match duration, high-intensity running and collisions were associated with variations in EIMD markers, suggesting recovery is dependent on individual match demands

Can Player Tracking Devices Monitor Changes in Internal Response During Multidirectional Running?

From Crossref journal articles via Jisc Publications RouterHistory: epub 2022-07-07, issued 2022-07-07Publication status: PublishedFunder: no funding associate

Can Player Tracking Devices Monitor Changes in Internal Response During Multidirectional Running?

This is an Accepted Manuscript of an article published by Taylor & Francis in Research Quarterly for Exercise and Sport on 07/07/2022, available online: 10.1080/02701367.2022.2092049Purpose: We examined the movement, physiological and muscle function responses to running with and without (i.e. linear) multiple directional changes to understand which measures of external demands better reflected changes in the internal response. Methods: Twelve team sport athletes completed a linear and multidirectional running trial during which movement characteristics, oxygen consumption (), blood lactate (B[La]) and heart rate (HR) were measured. Isometric peak torque of knee extensors and flexors was also assessed before and after each trial. Results: High speed running distance was higher during the linear trial (p < 0.001), whereas time at high metabolic power (p = 0.046), number of accelerations (p < 0.001), summated HR (p = 0.003) and B[La] (p = 0.002) were higher during the multidirectional trial. Integrated external to internal ratios of high-speed running: summated HR and high-speed running: total were different between multidirectional and linear trials (p ≤ 0.001). Conversely, high metabolic power: summated HR and high metabolic power: total were similar (p ≥ 0.246). Small decrements in knee flexor (p = 0.003) and extensor torque (p = 0.004) were observed after both trials. Conclusion: Time at high metabolic power better reflects the increased internal response during running with more directional changes than high speed runnin

The Unsuitability of Energy Expenditure Derived From Microtechnology for Assessing Internal Load in Collision-Based Activities

As accepted for publicationThis aim of this study was to examine the validity of energy expenditure derived from micro-technology when measured during a repeated effort rugby protocol. Sixteen male rugby players completed a repeated effort protocol comprising 3 sets of 6 collisions during which movement activity and energy expenditure (EEGPS) were measured using micro-technology. In addition, energy expenditure was also estimated from open circuit spirometry (EEVO2). Whilst related (r = 0.63, 90%CI 0.08-0.89), there was a systematic underestimation of energy expenditure during the protocol (-5.94 ± 0.67 kcalmin-1) for EEGPS (7.2 ± 1.0 kcalmin-1) compared to EEVO2 (13.2 ± 2.3 kcalmin-1). High-speed running distance (r = 0.50, 95%CI -0.66-0.84) was related to EEVO2, while Player Load was not (r = 0.37, 95%CI -0.81-0.68). Whilst metabolic power might provide a different measure of external load than other typically used micro-technology metrics (e.g. high-speed running, Player Load), it underestimates energy expenditure during intermittent team sports that involve collisions

Effect of movement‐evoked and tonic experimental pain on muscle force production

From Crossref journal articles via Jisc Publications RouterHistory: received 2023-05-24, accepted 2023-09-19, epub 2023-10-06, issued 2023-10-06, published 2023-10-06Article version: VoRPublication status: PublishedFunder: Wellcome Trust; FundRef: https://doi.org/10.13039/10.13039/100010269AbstractIntroductionWhen performing an exercise or a functional test, pain that is evoked by movement or muscle contraction could be a stronger stimulus for changing how individuals move compared to tonic pain. We investigated whether the decrease in muscle force production is larger when experimentally‐induced knee pain is directly associated to the torque produced (movement‐evoked) compared to a constant painful stimulation (tonic).MethodsTwenty‐one participants performed three isometric knee extension maximal voluntary contractions without pain (baseline), during pain, and after pain. Knee pain was induced using sinusoidal electrical stimuli at 10 Hz over the infrapatellar fat pad, applied continuously or modulated proportionally to the knee extension torque. Peak torque and contraction duration were averaged across repetitions and normalized to baseline.ResultsDuring tonic pain, participants reported lower pain intensity during the contraction than at rest (p &lt; 0.001), whereas pain intensity increased with contraction during movement‐evoked pain (p &lt; 0.001). Knee extension torque decreased during both pain conditions (p &lt; 0.001), but a larger reduction was observed during movement‐evoked compared to tonic pain (p &lt; 0.001). Participants produced torque for longer during tonic compared to movement‐evoked pain (p = 0.005).ConclusionOur results indicate that movement‐evoked pain was a more potent stimulus to reduce knee extension torque than tonic pain. The longer contraction time observed during tonic pain may be a result of a lower perceived pain intensity during muscle contraction. Overall, our results suggest different motor adaptation to tonic and movement‐evoked pain and support the notion that motor adaptation to pain is a purposeful strategy to limit pain. This mechanistic evidence suggests that individuals experiencing prevalently tonic or movement‐evoked pain may exhibit different motor adaptations, which may be important for exercise prescription