• Aging and Recovery After Resistance-Exercise-Induced Muscle Damage: Current Evidence and Implications for Future Research

      Fernandes, John F. T.; Lamb, Kevin L; Norris, Jonathan P; Moran, Jason; Drury, Benjamin; Borges, Nattai; Twist, Craig; University of Chester; Hartpury University; University of Essex; The University of Newcastle (Australia); Derbyshire County Cricket Club
      Aging is anecdotally associated with a prolonged recovery from resistance training, though current literature remains equivocal. This brief review considers the effects of resistance training on indirect markers of muscle damage and recovery (i.e., muscle soreness, blood markers, and muscle strength) in older males. With no date restrictions, four databases were searched for articles relating to aging, muscle damage, and recovery. Data from 11 studies were extracted for review. Of these, four reported worse symptoms in older compared with younger populations, while two have observed the opposite, and the remaining studies (n = 6) proposed no differences between age groups. It appears that resistance training can be practiced in older populations without concern for impaired recovery. To improve current knowledge, researchers are urged to utilize more ecologically valid muscle-damaging bouts and investigate the mechanisms which underpin the recovery of muscle soreness and strength after exercise in older populations.
    • Analysis of physical demands during youth soccer match-play: Considerations of sampling method and epoch length

      Doncaster, Greg; Page, Richard; White, Paul; Svenson, Robert; Twist, Craig; Edge HIll University; Stoke City FC; University of Chester (Taylor and Francis, 2019-11-27)
      The purpose of this study was to examine the physical match profiles of professional soccer players using 3 and 5 min fixed and rolling averages as well as fixed 1 min averages, with considerations to training prescription. Twenty-nine, professional U23 soccer outfield players competed across 17 competitive matches during the 2017/18 season, equating to a total of 130 separate physical match profiles. Match activities were recorded using global positioning system (GPS) devices with integrated micro-electrical mechanical systems (MEMS), recording total distance (TD), high-speed running (HSR) and metabolic power (MP). For each individual match profile and variable, 1, 3 and 5 min peak, post-peak, and average values were calculated using fixed-time epochs (FIXED) and rolling averages (ROLL). Linear mixed models were employed to examine the differences in the dependent variables as a function of the method of measurement. Results revealed significantly higher peak values, for relative TD, relative HSR and relative MP when employing the ROLL sampling method, in comparison to the FIXED method, for both 3 min and 5 min epoch lengths. Analysis of epoch length revealed significantly higher peak values, across all positions, for relative TD, relative HSR and MP for 1 min epochs, in comparison to 3 min and 5 min epochs. The data offers a novel insight into the appropriate identification of physical demands during youth soccer match-play. Researchers and practitioners should consider the sampling method and epoch length when assessing the physical demands of competitive match-play, as well as when designing and prescribing sport-specific conditioning drills.
    • Anthropometric and physical performance characteristics of top-elite, elite and non-elite youth female team handball players

      Moss, Samantha L.; McWhannell, Nicola; Michalsik, Lars B.; Twist, Craig (2015-02-16)
      In order to maximise the potential for success, developing nations need to produce superior systems to identify and develop talent, which requires comprehensive and up-to-date values on elite players. This study examined the anthropometric and physical characteristics of youth female team handball players (16.07 ± 1.30 y) in non-elite (n= 47), elite (n= 37) and top-elite players (n= 29). Anthropometric profiling included sum of eight skinfolds, body mass, stature, girths, breadths and somatotype. Performance tests included 20 m sprint, counter movement jump, throwing velocity, repeated shuttle sprint and jump ability test, and Yo-Yo Intermittent Recovery Test Level 1. Youth top-elite players had greater body mass, lean mass, stature, limb girths and breadths than elite and non-elite players, while only stature and flexed arm were higher in elite compared to non-elite players (all P < 0.05). Sum of skinfolds and waist-to-hip ratio were similar between groups (P > 0.05). Top-elite performed better in most performance tests compared to both elite and non-elite players (P < 0.05), although maximal and repeated10 m sprints were similar between standard (P > 0.05). Elite outperformed non-elite players in throwing velocity only. Findings reveal that non-elite players compare unfavourably to top-elite international European players in many anthropometric and performance characteristics, and differ in few characteristics compared to elite European club team players. This study is useful for emerging team handball nations in improving talent identification processes.
    • 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.
    • Carbohydrate and caffeine improves high intensity running of elite rugby league interchange players during simulated match play

      Clarke, Jon; Highton, Jamie M.; Close, Graeme L.; Twist, Craig; University of Chester; Warrington Wolves RLFC; Liverpool John Moores University (Lippincott, Williams & Wilkins, 2016-11-19)
      Carbohydrate and caffeine improves high intensity running of elite rugby league interchange players during simulated match play
    • Carbohydrate-protein ingestion during self-regulated simulated multiple-sprint sport activity

      Highton, Jamie M.; Nicholas, Ceri; Twist, Craig; Lamb, Kevin L.; University of Chester (2011-09)
    • Changes in anthropometry and performance, and their inter-relationships, across three seasons in elite youth rugby league players

      Waldron, Mark; Worsfold, Paul R.; Twist, Craig; Lamb, Kevin L.; University of New England, Australia ; University of Chester ; University of Chester ; University of Chester (Lippincott, Williams & Wilkins, 2014-11-30)
      This study investigated changes in anthropometry and performance, and their inter-relationships, across three consecutive seasons (under-15 to under-17 age group) in elite youth rugby league players. Each player took part in annual anthropometrical and performance assessments, comprising measurements of stature; body mass; limb lengths and circumference; skinfolds, predicted muscle cross-sectional area (CSA); 20 m speed, counter-movement jump height, vertical power and aerobic power. Lean body mass % changed (P < 0.05) between the under-15 (70.9 ± 5.9 %), under-16 (72.0 ± 5.8 %) and the under-17 age groups (74.1 ± 5.7 %). Likewise, predicted quadriceps muscle cross-sectional area (CSA) also changed (P < 0.05) between each age group (under-15 = 120.9 ± 37.8 cm2; under-16 = 133.2 ± 36.0 cm2; under-17 = 154.8 ± 28.3 cm2). Concomitant changes between the under-15 and under-16 group were found for 20 m speed (3.5 ± 0.1 cf. 3.4 ± 0.2 s; P = 0.008) and predicted jumping power (3611.3 ± 327.3 W cf. 4081.5 ± 453.9 W; P = 0.003). Both lean body mass and quadriceps muscle CSA consistently, related to both 20 m sprint time and jumping power, with r-values ranging between -0.39 to –0.63 (20 m sprint time) and 0.55 to 0.75 (jumping power). Our findings demonstrate the importance of gains in lean body mass across later-adolescence that support the ability to generate horizontal speed and predicted vertical power. This information should inform the expectations and subsequent training programs of elite rugby league practitioners.
    • Changes in locomotive rates during senior elite rugby league matches

      Sykes, Dave; Twist, Craig; Nicholas, Ceri; Lamb, Kevin L.; University of Chester (Taylor & Francis, 2011-08-05)
      The aim of this study was to quantify the changes in locomotive rates across the duration of senior elite rugby league matches.
    • A comparison of load-velocity and load-power relationships between well-trained young and middle-aged males during three popular resistance exercises.

      Fernandes, John; Lamb, Kevin L.; Twist, Craig (Lippincott, Williams & Wilkins, 2018-05-05)
      This study examined the load-velocity and load-power relationships among 20 young (age 21.0 ± 1.6 y) and 20 middle-aged (age 42.6 ± 6.7 y) resistance trained males. Participants performed three repetitions of bench press, squat and bent-over-row across a range of loads corresponding to 20 to 80% of one repetition maximum (1RM). Analysis revealed effects (P < 0.05) of group and load x group on barbell velocity for all three exercises, and interaction effects on power for squat and bent-over-row (P < 0.05). For bench press and bent-over-row, the young group produced higher barbell velocities, with the magnitude of the differences decreasing as load increased (ES; effect size 0.0 to 1.7 and 1.0 to 2.0, respectively). Squat velocity was higher in the young group than the middle-aged group (ES 1.0 to 1.7) across all loads, as was power for each exercise (ES 1.0 to 2.3). For all three exercises, both velocity and 1RM were correlated with optimal power in the middle-aged group (r = .613 to .825, P < 0.05), but only 1RM was correlated with optimal power (r = .708 to .867, P < 0.05) in the young group. These findings indicate that despite their resistance training, middle-aged males were unable to achieve velocities at low external loads and power outputs as high as the young males across a range of external resistances. Moreover, the strong correlations between 1RM and velocity with optimal power suggest that middle-aged males would benefit from training methods which maximise these adaptations.
    • A comparison of the FitroDyne and GymAware rotary encoders for quantifying peak and mean velocity during traditional multi-jointed exercises

      Fernandes, John; Lamb, Kevin L.; Clark, Cain; Moran, Jason; Drury, Ben; Garcia-Ramos, Amador; Twist, Craig; University of Chester & Hartpury University (Lippincott, Williams & Wilkins, 2018-11-05)
      The FitroDyne and GymAware rotary encoders are being increasingly used in resistance training to monitor movement velocity, but how closely their velocity outcomes agree is unknown. Consequently, this study aimed to determine the level of agreement between the FitroDyne and GymAware for the assessment of movement velocity in three resistance training exercises. Fifteen males performed three repetitions of bench press, back squat and bent-over-row exercises at 10% one repetition maximum increments (from 20 to 80%). For each repetition, the FitroDyne and GymAware recorded peak and mean barbell velocity (cm.s-1). Though strongly correlated (r = 0.79 to 1.00), peak velocity values for the GymAware were significantly lower than the FitroDyne for all exercises and loads. Importantly, the random errors between the devices, quantified via Bland and Altman's 95% limits of agreement, were unacceptable, ranging from ± 3.8 to 25.9 cm.s-1. Differences in mean velocity were smaller (and non-significant for most comparisons) and highly correlated (r = 0.86 to 1.00) between devices. Notwithstanding smaller random errors than for the peak values, mean values still reflected poor agreement (random errors between ± 2.1 to 12.0 cm.s-1). These findings suggest that the FitroDyne and GymAware cannot record peak or mean velocity with acceptable agreement, and should neither be employed interchangeably nor their data compared.
    • The concurrent validity of a rugby-specific Yo-Yo Intermittent Recovery Test (Level 1) for assessing match-related running performance

      Dobbin, Nick; Highton, Jamie M.; Moss, Samantha L.; Hunwicks, Richard; Twist, Craig; University of Chester; Rugby Football League, Leeds (Lippincott, Williams & Wilkins, 2018-06-01)
      This study investigated the concurrent validity of a rugby-specific high-intensity intermittent running test (HIIR) against the internal, external and perceptual responses to simulated match-play. Thirty-six rugby league players (age 18.5 ± 1.8 years; stature 181.4 ± 7.6 cm; body mass 83.5 ± 9.8 kg) completed the prone Yo-Yo IR1, of which sixteen also completed the Yo-Yo IR1, and 2 x ~20 min bouts of a simulated match-play (RLMSP-i). Most likely reductions in relative total, low-speed and high-speed distance, mean speed and time above 20 W·kg-1 (HMP) were observed between bouts of the RLMSP-i. Likewise, rating of perceived exertion (RPE) and percentage of peak heart rate (%HRpeak) were very likely and likely higher during the second bout. Pearson’s correlations revealed a large relationship for the change in relative distance (r = 0.57-0.61) between bouts with both Yo-Yo IR1 tests. The prone Yo-Yo IR1 was more strongly related to the RLMSP-i for change in repeated sprint speed (r = 0.78 cf. 0.56), mean speed (r = 0.64 cf. 0.36), HMP (r = 0.48 cf. 0.25), fatigue index (r = 0.71 cf. 0.63), %HRpeak (r = -0.56 cf. -0.35), RPEbout1 (r = -0.44 cf. -0.14), and RPEbout2 (r = -0.68 cf. -0.41) than the Yo-Yo IR1, but not for blood lactate concentration (r = -0.20 to -0.28 cf. -0.35 to -0.49). The relationships between prone Yo-Yo IR1 distance and measure of load during the RLMSP-i suggests it possesses concurrent validity and is more strongly associated with measures of training or match load than the Yo-Yo IR1 using rugby league 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.
    • Deteriorations in physical qualities during a 10-week unsupervised off-season period in academy rugby union players

      Twist, Craig; Williams, Jack; Dobbin, Nick; University of Chester; Manchester Metropolitan University
      Purpose: To determine the changes in physical qualities of academy rugby union players over a 10-week unsupervised off-season period. Methods: Body mass, jump height, sprint performance, and intermittent running (30:15 IFT) of 64 academy rugby union players (age = 17.2 ± 0.4 y) were recorded before and after the off-season. Results: Changes in body mass (+1.4 ± 1.3 kg), countermovement jump (-2.2 ± 1.2 cm), squat jump (-1.5 ± 1.8 cm), 10 m sprint (+0.06 ± 0.05 s), 40 m sprint (+0.13 ± 0.11 s) and 30:15 IFT (-0.8 ± 0.8 kmh-1) were observed (P < 0.001, d = -1.77 to 0.47). Only changes in body mass were greater in forwards than backs (P = 0.036, d = 0.46). Players with higher end-of-season body mass, squat jump and 30:15 IFT had greater off-season changes (P = < 0.001 to 0.044; d = 0.63 to 0.94), whilst the pre-post difference in body mass influenced CMJ (P = 0.005, d = 0.75) and 10 m momentum change (P <0.001, d = 1.61). Conclusion: Understanding the individuality of the changes in physical qualities of academy rugby union players during the off-season is important to ensure players return safely to pre-season training loads.
    • 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 effect of carbohydrate-protein ingestion on simulated multiple-sprint sport performance

      Highton, Jamie M.; Nicholas, Ceri; Twist, Craig; Lamb, Kevin L.; University of Chester (2011-04)
    • The effects of a carbohydrate-protein beverage on muscle function and performance following simulated multiple-sprint sport activity

      Highton, Jamie M.; Nicholas, Ceri; Twist, Craig; Lamb, Kevin L.; University of Chester (2010-09)
    • Effects of a four-week touch rugby and self-paced interval running intervention on health markers in active young men.

      Dobbin, Nick; Bloyce, Daniel; Hughes, Stephen; Twist, Craig (Springer, 2020-03-29)
      Background: Modified team sport activity has been proposed as effective exercise modality for promoting markers of health that are comparable or greater than continuous forms of activity. However, research using modified team sports is currently limited to sedentary populations using 2-3 sessions across a minimum of 8 weeks. Aim: To investigate the effects of a four-week touch rugby and self-paced interval running intervention on a range of health markers in active men. Methods: Sixteen participants (age 26.4 ± 6.4 years) were matched for age, demographic and physical activity before completing a single touch rugby (n = 8) or running (n = 8) session per week for four weeks. Measures of systolic and diastolic blood pressure, resting heart rate (RHR), body composition and biochemical status were recorded pre- and post-intervention. Results: ANCOVA analysis revealed between-group differences for impedance (P = 0.027), fat mass (P = 0.008), percentage body fat (P = 0.008) and fat free mass (P = 0.002), with greater changes after touch rugby. Systolic blood pressure decreased for both groups with greater reductions observed after touch rugby (P = 0.002). No between-group difference was observed for RHR, interleukin-6 or C-reactive protein (P > 0.05). Contrasting internal, external and perceptual loads were observed. Conclusion: The results of this study suggest that a single session of touch rugby over a 4-week period elicited greater improvements in body composition and SBP that self-paced running, with both equally beneficial for improving RHR, diastolic blood pressure and improved inflammatory status in active young men.
    • The effects of exercise-induced muscle damage on maximal intensity intermittent exercise performance

      Twist, Craig; Eston, Roger; University College Chester ; University of Exeter (Spring-Verlag, 2009-05-18)
      Exercise-induced muscle damage (EIMD) is a common occurrence following activities with a high eccentric component. Alterations to the torque-velocity relationship following EIMD would appear to have serious implications for athletic performance, particularly as they relate to impairment of maximal intensity exercise. However, this has been studied infrequently. The purpose of this study was to assess the effects of EIMD on maximal intermittent sprint performance. Ten male participants (age 22.4±3.2 years, height 178.6±5.2 cm, mass 80.6±10.7 kg) performed 10×6 s cycle ergometer sprints, interspersed with 24 s recovery against a load corresponding to 0.10 kp/kg and 10×10 m sprints from a standing start, each with 12 s active (walking) recovery. All variables were measured immediately before and at 30 min, 24, 48 and 72 h following a plyometric exercise protocol comprising of 10×10 maximal counter movement jumps. Repeated measures ANOVA showed significant changes over time (all P<0.05) for perceived soreness, plasma creatine kinase activity (CK), peak power output (PPO), sprint time and rate of fatigue. Soreness was significantly higher (P<0.01) than baseline values at all time intervals (3.1, 4.9, 5.5 and 3.2 at 30 min, 24, 48 and 72 h, respectively). CK was significantly elevated (P<0.05) at 24 h (239 IU/l) and 48 h (245 IU/l) compared to baseline (151 IU/l). PPO was significantly lower (P<0.05) than baseline (1,054 W) at all time intervals (888, 946, 852 and 895 W, at 30 min, 24, 48 and 72 h, respectively). The rate of fatigue over the ten cycling sprints was reduced compared to baseline, with the greatest reduction of 48% occurring at 48 h (P<0.01). This was largely attributed to the lower PPO in the initial repetitions, resulting in a lower starting point for the rate of fatigue. Values returned to normal at 72 h. Sprint times over 10 m were higher (P<0.05) at 30 min, 24 h and 48 h compared to baseline (1.96 s) with values corresponding to 2.01, 2.02 and 2.01 at 30 min, 24 h and 48 h, respectively. Values returned to baseline by 72 h. The results provide further evidence that, following a plyometric, muscle-damaging exercise protocol, the ability of the muscle to generate power is reduced for at least 3 days. This is also manifested by a small, but statistically significant reduction in very short-term (?2 s) intermittent sprint running performance. These findings have implications for appropriate training strategies in multiple sprint sports.
    • Effects of exercise-induced muscle damage on resting metabolic rate, sub-maximal running and post-exercise oxygen consumption

      Burt, Dean G.; Lamb, Kevin L.; Nicholas, Ceri; Twist, Craig; Staffordshire University; University of Chester (Taylor & Francis, 2013-04-08)
      Exercise-induced muscle damage (EIMD), described as the acute weakness of the musculature after unaccustomed eccentric exercise, increases oxidative metabolism at rest and during endurance exercise. However, it is not known whether oxygen uptake during recovery from endurance exercise is increased when experiencing symptoms of EIMD. Therefore, the purpose of this study was to investigate the effects of EIMD on physiological and metabolic responses before, during and after sub-maximal running. After a 12 h fast, eight healthy male participants completed baseline measurements comprising resting metabolic rate (RMR), indirect markers of EIMD, 10 min of sub-maximal running and 30 min of recovery to ascertain excess post-exercise oxygen consumption (EPOC). Measurements were then repeated at 24 and 48 h after 100 Smith-machine squats. Data analysis revealed significant (PB0.05) increases in muscle soreness and creatine kinase (CK) and decreases in peak knee extensor torque at 24 and 48 h after squatting exercise. Moreover, RMR, physiological, metabolic and perceptual responses during sub-maximal running and EPOC were increased in the two days after squatting exercise (PB0.05). It is suggested that the elevated RMR was a consequence of a raised energy requirement for the degradation and resynthesis of damaged muscle fibres. The increased oxygen demand during sub-maximal running after muscle damage was responsible for the increase in EPOC. Individuals engaging in unaccustomed resistance exercise that results in muscle damage should be mindful of the increases in resting energy expenditure and increased metabolic demand to exercise in the days that follow.