• 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.
    • Effort Perception

      Lamb, Kevin L.; Eston, Roger; Parfitt, Gaynor; University of Chester; University of South Australia (Oxford University Press, 2017-04-27)
      Research addressing children's perceptions of exercise effort (their ‘perceived exertion’) has appeared steadily in the scientific literature over the last 30 years. Accepting that the established Borg adult rating of perceived exertion (RPE) scale was not appropriate for children, investigators set about developing child-specific scales which employed numbers, words and/or images that were more familiar and understandable. Numerous studies have examined the validity and reliability of such scales as the CERT, PCERT and OMNI amongst children aged 5 to 16, across different modes of exercise (cycling, running, stepping, resistance exercise), protocols (intermittent vs. continuous, incremental vs. non-incremental) and paradigms (estimation vs. production). Such laboratory-based research has enabled the general conclusion that children can, especially with practice, use effort perception scales to differentiate between exercise intensity levels, and to self-regulate their exercise output to match various levels indicated on them. However, inconsistencies in the methodological approaches adopted diminish the certainty of some of the interpretations made by researchers. In addition, though often mentioned, the would-be application of effort perception in physical education and activity/health promotion contexts has been relatively ignored. Accordingly, the scope for research in this applied domain is now considerable.
    • Misperception: No evidence to dismiss RPE as regulator of moderate-intensity exercise

      Eston, Roger; Coquart, J.; Lamb, Kevin L.; Parfitt, Gaynor; University of South Australia; Universite´ de Rouen; University of Chester (American College of Sports Medicine, 2015-12-01)
      Dear Editor-in-Chief, Shaykevich et al. (7) demonstrate the efficacy of auditory feedback anchored at 75% of age-predicted HRmax to regulate intensity (claimed as ‘‘moderate’’) during several 20-min bouts of cycling. Their technical approach is novel, but 76% HRmax is the upper limit of moderate intensity, so given the large error in age-predicted HRmax, it is unlikely that their exercise bandwidth was ‘‘moderate’’ for all participants. This is not our major concern, but it reveals one among other inaccuracies: the most serious include training, interpretation, and inferences relating to the RPE.
    • Muscle function after exercise-induced muscle damage: Considerations for athletic performance in children and adults

      Eston, Roger; Byrne, Christopher; Twist, Craig; University of Wales, Bangor ; DSO National Laboratories, Republic of Singapore ; NEWI/University of Wales, Bangor (Elsevier, 2004)
    • Neuromuscular function after exercise-induced muscle damage: Theoretical and applied implications

      Byrne, Christopher; Twist, Craig; Eston, Roger; DSO National Laboratories, Republic of Singapore ; NEWI/University of Wales, Bangor ; University of Wales, Bangor (Adis, 2004)
      Exercise-induced muscle damage is a well documented phenomenon particularly resulting from eccentric exercise. When eccentric exercise is unaccustomed or is performed with an increased intensity or duration, the symptoms associated with muscle damage are a common outcome and are particularly associated with participation in athletic activity. Muscle damage results in an immediate and prolonged reduction in muscle function, most notably a reduction in force-generating capacity, which has been quantified in human studies through isometric and dynamic isokinetic testing modalities. Investigations of the torque-angular velocity relationship have failed to reveal a consistent pattern of change, with inconsistent reports of functional change being dependent on the muscle action and/or angular velocity of movement. The consequences of damage on dynamic, multi-joint, sport-specific movements would appear more pertinent with regard to athletic performance, but this aspect of muscle function has been studied less often. Reductions in the ability to generate power output during single-joint movements as well as during cycling and vertical jump movements have been documented. In addition, muscle damage has been observed to increase the physiological demand of endurance exercise and to increase thermal strain during exercise in the heat. The aims of this review are to summarise the functional decrements associated with exercise-induced muscle damage, relate these decrements to theoretical views regarding underlying mechanisms (i.e. sarcomere disruption, impaired excitation-contraction coupling, preferential fibre type damage, and impaired muscle metabolism), and finally to discuss the potential impact of muscle damage on athletic performance.
    • Reliability of ratings of perceived exertion during progressive treadmill exercise.

      Lamb, Kevin L.; Eston, Roger; Corns, David; University College Chester (Elsevier, 1999-10)
      OBJECTIVE: To assess the test-retest reliability (repeatability) of Borg's 6-20 rating of perceived exertion (RPE) scale using a more appropriate statistical technique than has been employed in previous investigations. The RPE scale is used widely in exercise science and sports medicine to monitor and/or prescribe levels of exercise intensity. The "95% limits of agreement" technique has recently been advocated as a better means of assessing within-subject (trial to trial) agreement than traditional indicators such as Pearson and intraclass correlation coefficients. METHODS: Sixteen male athletes (mean (SD) age 23.6 (5.1) years) completed two identical multistage (incremental) treadmill running protocols over a period of two to five days. RPEs were requested and recorded during the final 15 seconds of each three minute stage. All subjects successfully completed at least four stages in each trial, allowing the reliability of RPE responses to be examined at each stage. RESULTS: The 95% limits of agreement (bias +/- 1.96 x SDdiff) were found to widen as exercise intensity increased: 0.88 (2.02) RPE units (stage 1), 0.25 (2.53) RPE units (stage 2), -0.13 (2.86) RPE units (stage 3), and -0.13 (2.94) RPE units (stage 4). Pearson correlations (0.81, 0.72, 0.65, and 0.60) and intraclass correlations (0.82, 0.80, 0.77, and 0.75) decreased as exercise intensity increased. CONCLUSIONS: These findings question the test-retest reliability of the RPE scale when used to monitor subjective estimates of exercise intensity in progressive (or graded) exercise tests.
    • Statistical analyses in the physiology of exercise and kinanthropometry

      Winter, Edward; Eston, Roger; Lamb, Kevin L. (Routledge, 2001-10-01)
    • The validity of predicting maximal oxygen uptake from a perceptually-regulated graded exercise test

      Eston, Roger; Lamb, Kevin L.; Parfitt, Gaynor; King, Nicholas; University of Exeter ; University of Chester ; University of Exeter ; University of Wales, Bangor (Springer-Verlag, 2005-04-07)
      The purpose of this study was to assess the validity of predicting maximal oxygen uptake from sub-maximal values elicited during a perceptually-regulated exercise test. We hypothesised that the strong relationship between the ratings of perceived exertion (RPE) and would enable to be predicted and that this would improve with practice. Ten male volunteers performed a graded exercise test (GXT) to establish followed by three sub-maximal RPE production protocols on a cycle ergometer, each separated by a period of 48 h.