• The assessment of total energy expenditure during a 14-day ‘in-season’ period of professional rugby league players using the Doubly Labelled Water method

      Morehen, James C.; Bradley, Warren J.; Clarke, Jon; Twist, Craig; Hambly, Catherine; Speakman, John R.; Morton, James P.; Close, Graeme L.; Liverpool John Moores University; Widnes Vikings Rugby League; University of Chester; University of Aberdeen (Human Kinetics, 2016-10-31)
      Rugby League is a high-intensity collision sport competed over 80-minutes. Training loads are monitored to maximise recovery and assist in the design of nutritional strategies although no data are available on the Total Energy Expenditure (TEE) of players. We therefore assessed Resting Metabolic Rate (RMR) and TEE in six Super-League players over two consecutive weeks in-season including one-game per week. Fasted RMR was assessed followed by a baseline urine sample before oral administration of a bolus dose of hydrogen (deuterium 2H) and oxygen (18O) stable isotopes in the form of water (2H218O). Every 24 hours thereafter, players provided urine for analysis of TEE via DLW method. Individual training-load was quantified using session rating of perceived exertion (sRPE) and data were analysed using magnitude-based inferences. There were unclear differences in RMR between forwards and backs (7.7 ± 0.5 cf. 8.0 ± 0.3 MJ, respectively). Indirect calorimetry produced RMR values most likely lower than predictive equations (7.9 ± 0.4 cf. 9.2 ± 0.4 MJ, respectively). A most likely increase in TEE from week-1 to -2 was observed (17.9 ± 2.1 cf. 24.2 ± 3.4 MJ) explained by a most likely increase in weekly sRPE (432 ± 19 cf. 555 ± 22 AU), respectively. The difference in TEE between forwards and backs was unclear (21.6 ± 4.2 cf. 20.5 ± 4.9 MJ, respectively). We report greater TEE than previously reported in rugby that could be explained by the ability of DLW to account for all match and training-related activities that contributes to TEE.
    • Associations between selected training stress measures and fitness changes in male soccer players

      Rabbani, Alireza; Kargarfard, Mehdi; Castagna, Carlo; Clemente, Filipe M.; Twist, Craig; University of Chester (Human Kinetics, 2019-01-24)
      Purpose: The purpose of this study was to investigate the relationship of accumulated Global Positioning System (GPS)-accelerometer-based and heart rate (HR)-based training metrics to changes in high-intensity intermittent running capacity during an in-season phase in professional soccer players. Method: Eleven male professional players (mean ± SD, age: 27.2 ± 4.5 years) performed the 30-15 Intermittent Fitness Test (30-15IFT) before and after a five-week in-season training phase, and the final velocity (VIFT) was considered as players’ high-intensity intermittent running capacity. During all sessions, Edwards’ training impulse (Edwards’ TRIMP), Banister’s TRIMP, Z5 TRIMP, training duration, total distance covered, New Body Load (NBL), high-intensity running performance (distance covered above 14.4 km•h-1), and very high-intensity running performance (distance covered above 19.8 km•h-1) were recorded. Results: The players’ VIFT showed a most likely moderate improvement (+4.3%, 90% confidence limits [3.1; 5.5%], effect size ES, 0.70 [0.51; 0.89]). Accumulated NBL, Banister’s TRIMP and Edwards’ TRIMP showed large associations (r = 0.51 to 0.54) with changes in VIFT. Very large relationship was also observed between accumulated Z5 TRIMP (r= 0.72) with changes in VIFT. Large-to-nearly perfect within-individual relationships were observed between NBL and some of the other training metrics (i.e., Edwards’ TRIMP, Banister’s TRIMP, training duration, and total distance) in 10 out of 11 players. Conclusions: HR-based training metrics can be used to monitor high-intensity intermittent running capacity changes in professional soccer players. The dose-response relationship is also largely detected using accelerometer-based metrics (i.e., NBL) to track changes in high-intensity intermittent running capacity of professional soccer players.
    • Criterion and construct validity of an isometric mid-thigh pull dynamometer for assessing whole body strength in professional rugby league players

      Dobbin, Nicholas; Hunwicks, Richard; Jones, Ben; Till, Kevin; Highton, Jamie M.; Twist, Craig; University of Chester, Rugby Football League, Leeds Beckett University (Human Kinetics, 2018-02-31)
      Purpose: The purpose of this study was to examine the criterion and construct validity of an isometric mid-thigh pull dynamometer to assess whole body strength in professional rugby league players. Methods: Fifty-six male rugby league players, (33 senior and 23 youth professional players) performed four isometric mid-thigh pull efforts (i.e. two on the dynamometer and two on the force platform) in a randomised and counterbalanced order. Results: Isometric peak force was underestimated (P<0.05) using the dynamometer compared to the force platform (95% LoA: -213.5 ± 342.6 N). Linear regression showed that peak force derived from the dynamometer explained 85% (adjusted R2 = 0.85, SEE = 173 N) of the variance in the dependent variable, with the following prediction equation derived: predicted peak force = [1.046 * dynamometer peak force] + 117.594. Cross-validation revealed a non-significant bias (P>0.05) between the predicted and peak force from the force platform, and an adjusted R2 (79.6%), that represented shrinkage of 0.4% relative to the cross-validation model (80%). Peak force was greater for the senior compared to youth professionals using the dynamometer (2261.2 ± 222 cf. 1725.1 ± 298.0 N, respectively; P<0.05). Conclusion: The isometric mid-thigh pull assessed using a dynamometer underestimates criterion peak force but is capable of distinguishing muscle function characteristics between professional rugby league players of different standards.
    • The discriminant validity of standardised testing battery and its ability to differentiate anthropometric and physical characteristics between youth, academy and senior professional rugby league players

      Dobbin, Nicholas; Moss, Samantha L.; Highton, Jamie M.; Twist, Craig; University of Chester (Human Kinetics, 2019-01-31)
      Purpose: To assess a standardised testing battery’s ability to differentiate anthropometric and physical qualities between youth, academy and senior rugby league players, and determine the discriminant validity of the battery. Methods: A total of 729 rugby league players from multiple clubs within England categorised as youth (n = 235), academy (n = 362) and senior (n = 132) players completed a standardised testing battery that included the assessment of anthropometric and physical characteristics during preseason. Data was analysed using magnitude-based inferences and discriminant analysis. Results: Academy players were most likely taller and heavier than youth players (effect size (ES) = 0.64 to 1.21), with possibly to most likely superior CMJ, medicine ball throw and prone Yo-Yo IR1 performance (ES = 0.23 to 1.00). Senior players were likely to most likely taller and heavier (ES = 0.32 to 1.84), with possibly to most likely superior 10 and 20 m sprint times, CMJ, CoD, medicine ball throw and prone Yo-Yo IR1 compared to youth and academy (ES = -0.60 to 2.06). The magnitude of difference appeared to be influenced by playing position. For the most part, the battery possessed discriminant validity with an accuracy of 72.2%. Conclusion: The standardised testing battery differentiates anthropometric and physical qualities of youth, academy and senior players as a group and, in most instances, within positional groups. Furthermore, the battery is able to discriminate between playing standards with good accuracy and might be included in future assessments and rugby league talent identification.
    • The effects of in-season, low-volume sprint interval training with and without sport-specific actions on the physical characteristics of elite academy rugby league players

      Dobbin, Nick; Highton, Jamie M.; Moss, Samantha; Twist, Craig (Human Kinetics, 2020-05-01)
      Purpose: To determine the utility of a running and rugby-specific, in-season sprint interval interventions in professional rugby league players. Methods: Thirty-one professional academy rugby players were assigned to a rugby-specific (SITr/s, n = 16) or running (SITr, n = 15) sprint interval training group. Measures of speed, power, change of direction (CoD) ability, prone Yo-Yo IR1 performance and heart rate recovery (HRR) were taken before and after the 2-week intervention as were sub-maximal responses to the prone Yo-Yo IR1. Internal, external and perceptual responses were collected during SITr/s/SITr, with wellbeing and neuromuscular function assessed before each session. Results: Despite contrasting (possible to most likely) internal, external and perceptual responses to the SIT interventions, possible to most likely within-group improvements in physical characteristics, HRR and sub-maximal responses to the prone Yo-Yo IR1 were observed after both interventions. Between-group analysis favoured the SITr/s intervention (trivial to moderate) for changes in 10 m sprint time, CMJ, change of direction and medicine ball throw as well as sub-maximal (280-440 m) high metabolic power, PlayerLoad™ and acceleratory distance during the prone Yo-Yo IR1. Overall changes in wellbeing or neuromuscular function were unclear. Conclusion: Two-weeks of SITr/s and SITr was effective for improving physical characteristics, HRR and sub-maximal responses to the prone Yo-Yo IR1, with no clear change in wellbeing and neuromuscular function. Between-group analysis favoured the SITr/s group, suggesting that the inclusion of sport- specific actions should be considered for in-season conditioning of rugby league players.
    • Estimates of Energy Intake and Expenditure in Elite Female Touch Players During an International Tournament

      Marsh, Nicola; Dobbin, Nick; Twist, Craig; Curtis, Chris; St Mary’s University; University of Chester (Human Kinetics, 2017-12-31)
      This study assessed energy intake and expenditure of international female Touch players during an international tournament. Energy intake (food diary) and expenditure (accelerometer, global positioning system) were recorded for 16 female Touch players during a four-day tournament, competing in 8.0 ± 1.0 matches; two on days one, two and four, and three on day three. Total daily energy expenditure (43.6 ± 3.1 Kcal.kg-1 body mass (BM)) was not different (P > 0.05) from energy intake (39.9 ± 9.4 Kcal.kg-1 BM). Carbohydrate intakes were below current recommendations (6-10 g.kg-1 BM) on days one (4.4 ± 0.6 g.kg-1 BM) and three (4.7 ± 1.0 g.kg-1 BM) and significantly below (P < 0.05) on day two (4.1 ± 1.0 g.kg-1 BM). Protein and fat intakes were consistent with recommendations (protein; 1.2 - 2.0 g.kg-1 BM, fat; 20 - 35 % total Kcal) across days one to three (protein; 1.9 ± 0.8, 2.2 ± 0.8 & 2.0 ± 0.7 g.kg-1 BM, fat; 35.6 ± 6.8, 38.5 ± 6.4 & 35.9 ± 5.4 % total Kcal). Saturated fat intakes were greater (P < 0.05) than recommendations (10 % total Kcal) on days one to three (12.4 ± 2.9, 14.2 ± 5.1 & 12.7 ± 3.5 % total Kcal). On average, female Touch players maintained energy balance. Carbohydrate intakes appeared insufficient and might have contributed to the reduction (P < 0.05) in high-intensity running on day three. Further research might investigate the applicability of current nutrition recommendations and the role of carbohydrate in multi-match, multi-day tournaments.
    • Factors affecting the anthropometric and physical characteristics of elite academy rugby league players: a multi-club study.

      Dobbin, Nicholas; Moss, Samantha L.; Highton, Jamie M.; Twist, Craig; University of Chester (Human Kinetics, 2019-01-24)
      Purpose: To investigate the factors affecting the anthropometric and physical characteristics of elite academy rugby league players. Methods: One hundred and ninety-seven elite academy rugby league players (age = 17.3 ± 1.0 years) from five Super League clubs completed measures of anthropometric and physical characteristics during a competitive season. The interaction between, and influence of contextual factors on characteristics was assessed using linear mixed modelling. Results: Associations were observed between several anthropometric and physical characteristics. All physical characteristics improved during preseason and continued to improve until mid-season where thereafter 10 m sprint (η2 = 0.20 cf. 0.25), CMJ (η2 = 0.28 cf. 0.30) and prone Yo-Yo Intermittent Recovery Test (Yo-Yo IR) (η2 = 0.22 cf. 0.54) performance declined. Second (η2 = 0.17) and third (η2 = 0.16) years were heavier than first years, whilst third years had slower 10 m sprint times (η2 = 0.22). Large positional variability was observed for body mass, 20 m sprint time, medicine ball throw, countermovement jump, and prone Yo-Yo IR1. Compared to bottom-ranked teams, top demonstrated superior 20 m (η2 = -0.22) and prone Yo-Yo IR1 (η2 = 0.26) performance whilst middle-ranked teams reported higher CMJ height (η2 = 0.26) and prone Yo-Yo IR1 distance (η2 = 0.20), but slower 20 m sprint times (η2 = 0.20). Conclusion: These findings offer practitioners designing training programmes for academy rugby league players insight into the relationships between anthropometric and physical characteristics and how they are influenced by playing year, league ranking, position and season phase.
    • Influence of Knowledge of Task Endpoint on Pacing and Performance During Simulated Rugby League Match Play

      Mullen, Thomas; Twist, Craig; Highton, Jamie M.; University of Chester (Human Kinetics, 2017-10-31)
      Purpose: To examine the influence of knowledge of exercise duration on pacing and performance during simulated rugby league match play. Methods: Thirteen male university rugby players completed 3 simulated rugby league matches (RLMSP-i) on separate days in a random order. In a control trial, participants were informed that they would be performing 2 × 23-min bouts (separated by 20 min) of the RLMSP-i (CON). In a second trial, participants were informed that they would be performing 1 × 23-min bout of the protocol but were then asked to perform another 23-min bout (DEC). In a third trial, participants were not informed of the exercise duration and performed 2 × 23-min bouts (UN). Results: Distance covered and high-intensity running were higher in CON (4813 ± 167 m, 26 ± 4.1 m/min) than DEC (4764 ± 112 m, 25.2 ± 2.8 m/min) and UN (4744 ± 131 m, 24.4 m/min). Compared with CON, high-intensity running and peak speed were typically higher for DEC in bout 1 and lower in bout 2 of the RLMSP-i, while UN was generally lower throughout. Similarly, DEC resulted in an increased heart rate, blood lactate, and rating of perceived exertion than CON in bout 1, whereas these variables were lower throughout the protocol in UN. Conclusions: Pacing and performance during simulated rugby league match play depend on an accurate understanding of the exercise endpoint. Applied practitioners should consider informing players of their likely exercise duration to maximize running.
    • ‘Life in the Travelling Circus’: A Study of Loneliness, Work Stress, and Money Issues in Touring Professional Golf

      Fry, John; Bloyce, Daniel; Myerscough College; University of Chester (Human Kinetics, 2017-06-31)
      This article examines the effects of globalization on the well-being of migrant professional athletes. Interviews with 20 touring professional golfers reveal that players experience many of the personal problems – such as loneliness, isolation, low decision latitude, low social support, and effort-reward imbalance – which have been identified as “strong predictors of mental ill-health” (Leka & Jain, 2010, p. 65). Feelings of loneliness and isolation developed as players were regularly apart from family and friends, and spent most of their time with other golfers whom they had somewhat superficial relationships with. These feelings coupled with, for many, uncertain income generated through golf added further to their work-related anxieties. Overall, results highlight the importance of considering how workplace anxieties and vulnerabilities impact on athlete migrants’ health and well-being.
    • A Narrative Review on Female Physique Athletes: The Physiological and Psychological Implications of Weight Management Practices

      Alwan, Nura; Moss, Samantha L.; Elliott-Sale, Kisrty; Davies, Ian; Kevin, Enright; Liverpool John Moores University; University of Chester; Nottingham Trent University (Human Kinetics, 2019-06-13)
      Physique competitions are events in which aesthetic appearance and posing ability are valued above physical performance. Female physique athletes are required to possess high lean body mass and extremely low fat mass in competition. As such, extended periods of reduced energy intake and intensive training regimens are utilised with acute weight loss practices at the end of the pre-competition phase. This represents an increased risk for chronic low energy availability and associated symptoms of Relative Energy Deficiency in Sport, compromising both psychological and physiological health. Available literature suggests that a large proportion of female physique athletes report menstrual irregularities (e.g., amenorrhea and oligomenorrhea), which are unlikely to normalise immediately post-competition. Furthermore, the tendency to reduce intakes of numerous essential micronutrients is prominent among those using restrictive eating patterns. Following competition reduced resting metabolic rate, and hyperphagia, are also a concern for these female athletes, which can result in frequent weight cycling, distorted body image and disordered eating/eating disorders. Overall, female physique athletes are an understudied population and the need for more robust studies to detect low energy availability and associated health effects is warranted. This narrative review aims to define the natural female physique athlete, explore some of the physiological and psychological implications of weight management practices experienced by female physique athletes and propose future research directions.
    • The physiological and perceptual effects of stochastic simulated rugby league match play

      Mullen, Thomas; Twist, Craig; Highton, Jamie; University of Chester
      Purpose: To examine responses to a simulated rugby league protocol designed to include more stochastic commands, and therefore require greater vigilance, than traditional team sport simulation protocols. Methods: Eleven male university rugby players completed two trials (randomised and control) of a rugby league movement simulation protocol, separated by 7-10 days. The control trial (CON) consisted of 48 repeated ~115 s cycles of activity. The stochastic simulation (STOCH) was matched for the number and types of activity performed every 5.45 min in CON, but included no repeated cycles of activity. Movement using GPS, heart rate, RPE and Stroop test performance were assessed throughout. MVC peak torque, voluntary activation (%) and global task load were assessed after exercise. Results: The mean mental demand of STOCH was higher than CON (Effect size (ES) = 0.56; ±0.69). Mean sprint speed was higher in STOCH (22.5 ± 1.4 vs. 21.6 ± 1.6 km∙h-1; ES = 0.50; ±0.55), which was accompanied by a higher RPE (14.3 ± 1.0 vs. 13.0 ± 1.4; ES = 0.87; ±0.67) and a greater number of errors in the Stroop Test (10.3 ± 2.5 vs. 9.3 ± 1.4 errors; ES = 0.65; ±0.83). MVC peak torque (CON = -48.4 ± 31.6 N∙m, STOCH = -39.6 ± 36.6 N∙m) and voluntary activation (CON = -8.3 ± 4.8%, STOCH = -6.0 ± 4.1%) was similarly reduced in both trials. Conclusions: Providing more stochastic commands, which requires greater vigilance, might alter performance and associated physiological, perceptual and cognitive responses to team sport simulations.
    • Physiological, perceptual and performance responses associated with self-selected versus standardized recovery periods during a repeated sprint protocol in elite youth football players: A preliminary study

      Gibson, Neil; Brownstein, Callum; Ball, Derek; Twist, Craig; Heriot-Watt University; Northumbria University; University of Chester (Human Kinetics, 2017-05-31)
      Purpose: To examine the physiological and perceptual responses of youth footballers to a repeated sprint protocol employing standardized and self-selected recovery. Methods: Eleven male participants (13.7 ± 1.1 years) performed a repeated sprint assessment comprising 10 x 30 m efforts. Employing a randomized crossover design, repeated sprints were performed using 30 s and self-selected recovery periods. Heart rate was monitored continuously with ratings of perceived exertion (RPE) and lower body muscle power measured 2 min after the final sprint. The concentration of blood lactate was measured at 2, 5 and 7 minutes post sprinting. Magnitude of effects were reported using effect size (ES) statistics ± 90% confidence interval and percentage differences. Differences between trials were examined using paired student t-tests (p < 0.05). Results: Self-selected recovery resulted in most likely shorter recovery times (57.7%; ES 1.55 ± 0.5; p < 0.01), a most likely increase in percentage decrement (65%; ES 0.36 ±1 0.21; p = 0.12), very likely lower heart rate recovery (-58.9%; ES -1.10 ± 0.72; p = 0.05), and likely higher blood lactate concentration (p = 0.08-0.02). Differences in lower body power and RPE were unclear (p > 0.05). Conclusion: Self-selected recovery periods compromise repeated sprint performance.
    • Player responses to match and training demands during an intensified fixture schedule in professional rugby league: A case study.

      Twist, Craig; Highton, Jamie M.; Daniels, Matthew; Mill, Nathan; Close, Graeme L.; University of Chester; St Helens RFC; Liverpool John Moores (Human Kinetics, 2017-09-30)
      Player loads and fatigue responses are reported in 15 professional rugby league players (24.3 ± 3.8 y) during a period of intensified fixtures. Repeated measures of internal and external loads, perceived well-being, and jump flight time were recorded across 22 d, comprising 9 training sessions and matches on days 5, 12, 15, and 21 (player exposure: 3.6 ± 0.6 matches). Mean training loads (session rating of perceived exertion × duration) between matches were 1177, 1083, 103, and 650 AU. Relative distance in match 1 (82 m/min) and match 4 (79 m/min) was very likely lower in match 2 (76 m/min) and likely higher in match 3 (86 m/min). High-intensity running (≥5.5 m/s) was likely to very likely lower than match 1 (5 m/min) in matches 2–4 (2, 4, and 3 m/min, respectively). Low-intensity activity was likely to very likely lower than match 1 (78 m/min) in match 2 (74 m/min) and match 4 (73 m/min) but likely higher in match 3 (81 m/min). Accumulated accelerometer loads for matches 1–4 were 384, 473, 373, and 391 AU, respectively. Perceived well-being returned to baseline values (~21 AU) before all matches but was very likely to most likely lower the day after each match (~17 AU). Prematch jump flight times were likely to most likely lower across the period, with mean values of 0.66, 0.65, 0.62, and 0.64 s before matches 1–4, respectively. Across a 22-d cycle with fixture congestion, professional rugby league players experience cumulative neuromuscular fatigue and impaired match running performance.
    • The Relationship Between Match-Play Characteristics of Elite Rugby League and Indirect Markers of Muscle Damage

      Oxendale, Chelsea; Twist, Craig; Daniels, Matthew; Highton, Jamie M.; University of Chester; St Helens Rugby League Club (Human Kinetics, 2016)
      Purpose: 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.
    • Sex-related changes in physical performance, wellbeing and neuromuscular function of elite Touch players during a four-day international tournament.

      Dobbin, Nick; Highton, Jamie M.; Thorpe, M.; Twist, Craig; University of Chester; Manchester Metropolitan University
      Purpose: To examine the within- and between-sex physical performance, wellbeing and neuromuscular function responses across a four-day international touch rugby (Touch) tournament. Methods: Twenty females and twenty-one males completed measures of wellbeing (fatigue, soreness, sleep, mood, stress) and neuromuscular function (countermovement jump (CMJ) height, peak power output (PPO) and peak force (PF)) during a 4-day tournament with internal, external and perceptual loads recorded for all matches. Results: Relative and absolute total, low- (females) and high-intensity distance was lower on day 3 (males and females) (ES = -0.37 to -0.71) compared to day 1. Mean heart rate was possibly to most likely reduced during the tournament (except day 2 males) (ES = -0.36 to -0.74), whilst RPE-TL was consistently higher in females (ES = 0.02 to 0.83). The change in mean fatigue, soreness and overall wellbeing were unclear to most likely lower (ES = -0.33 to -1.90) across the tournament for both sexes, with greater perceived fatigue and soreness in females on days 3-4 (ES = 0.39 to 0.78). Jump height and PPO were possibly to most likely lower across days 2-4 (ES = -0.30 to -0.84), with greater reductions in females (ES = 0.21 to 0.66). Wellbeing, CMJ height, and PF were associated with changes in external, internal and perceptual measures of load across the tournament (2 = -0.37 to 0.39). Conclusions: Elite Touch players experience reductions in wellbeing, neuromuscular function and running performance across a 4-day tournament, with notable differences in fatigue and running between males and females, suggesting sex-specific monitoring and intervention strategies are necessary.
    • Slowing the Reconstitution of W′ in Recovery With Repeated Bouts of Maximal Exercise

      Chorley, Alan; Bott, Richard; Marwood, Simon; Lamb, Kevin L.; University of Chester; Liverpool Hope University (Human Kinetics, 2019-02-01)
      Purpose: This study examined the partial reconstitution of the work capacity above critical power (W′) following successive bouts of maximal exercise using a new repeated ramp test, against which the fit of an existing W′ balance (W'bal) prediction model was tested. Methods: Twenty active adults, consisting of trained cyclists (n = 9; age 43 [15] y, V˙ O2max 61.9 [8.5] mL·kg−1·min−1) and untrained cyclists (n = 11; age 36 [15] y, V˙ O2max 52.4 [5.8] mL·kg−1·min−1) performed 2 tests 2 to 4 d apart, consisting of 3 incremental ramps (20 W·min−1) to exhaustion interspersed with 2-min recoveries. Results: Intratrial differences between recoveries demonstrated significant reductions in the amount of W′ reconstituted for the group and both subsets (P < .05). The observed minimal detectable changes of 475 J (first recovery) and 368 J (second recovery) can be used to monitor changes in the rate of W′ reconstitution in individual trained cyclists. Intertrial relative reliability of W′ reconstitution was evaluated by intraclass correlation coefficients for the group (≥.859) and the trained (≥.940) and untrained (≥.768) subsets. Absolute reliability was evaluated with typical error (TE) and coefficient of variation (CV) for the group (TE ≤ 559 J, CV ≤ 9.2%), trained (TE ≤ 301 J, CV ≤ 4.7%), and untrained (TE ≤ 720 J, CV ≤ 12.4%). Conclusions: The reconstitution of W′ is subject to a fatiguing effect hitherto unaccounted for in W'bal prediction models. Furthermore, the W'bal model did not provide a good fit for the repeated ramp test, which itself proved to be a reliable test protocol.
    • The Unsuitability of Energy Expenditure Derived From Microtechnology for Assessing Internal Load in Collision-Based Activities

      Highton, Jamie M.; Mullen, Thomas; Norris, Jonathan; Oxendale, Chelsea; Twist, Craig (Human Kinetics, 2016-05-25)
      This 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 kcalmin-1) for EEGPS (7.2 ± 1.0 kcalmin-1) compared to EEVO2 (13.2 ± 2.3 kcalmin-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.