• The Application of Critical Power, the Work Capacity above Critical Power (W'), and its Reconstitution: A Narrative Review of Current Evidence and Implications for Cycling Training Prescription

      Chorley, Alan; Lamb, Kevin L; University of Chester
      The two-parameter critical power (CP) model is a robust mathematical interpretation of the power–duration relationship, with CP being the rate associated with the maximal aerobic steady state, and W' the fixed amount of tolerable work above CP available without any recovery. The aim of this narrative review is to describe the CP concept and the methodologies used to assess it, and to summarize the research applying it to intermittent cycle training techniques. CP and W' are traditionally assessed using a number of constant work rate cycling tests spread over several days. Alternatively, both the 3-min all-out and ramp all-out protocols provide valid measurements of CP and W' from a single test, thereby enhancing their suitability to athletes and likely reducing errors associated with the assumptions of the CP model. As CP represents the physiological landmark that is the boundary between heavy and severe intensity domains, it presents several advantages over the de facto arbitrarily defined functional threshold power as the basis for cycle training prescription at intensities up to CP. For intensities above CP, precise prescription is not possible based solely on aerobic measures; however, the addition of the W' parameter does facilitate the prescription of individualized training intensities and durations within the severe intensity domain. Modelling of W' reconstitution extends this application, although more research is needed to identify the individual parameters that govern W' reconstitution rates and their kinetics
    • Changes in physical activity and sedentary behaviour due to enforced covid-19-related lockdown and movement restrictions: A protocol for a systematic review and meta-analysis

      Kite, Chris; Lagojda, Lukasz; Clark, Cain C T; Uthman, Olalekan; Denton, Francesca; McGregor, Gordon; Harwood, Amy E; Atkinson, Lou; Broom, David R; Kyrou, Ioannis; et al. (MDPI, 2021-05-14)
      Prolonged lockdown/restriction measures due to the COVID-19 pandemic have reportedly impacted opportunities to be physically active for a large proportion of the population in affected countries globally. The exact changes to physical activity and sedentary behaviours due to these measures have not been fully studied. Accordingly, the objective of this PROSPERO-registered systematic review is to evaluate the available evidence on physical activity and sedentary behaviours in the general population during COVID-19-related lockdown/restriction measures, compared to prior to restrictions being in place. Defined searches to identify eligible studies published in English, from November 2019 up to the date of submission, will be conducted using the following databases: CENTRAL, MEDLINE, EMBASE, CINAHL, SPORTDiscus, PSYCinfo, Coronavirus Research Database, Public Health Database, Publicly Available Content Database, SCOPUS, and Google Scholar. The applied inclusion criteria were selected to identify observational studies with no restrictions placed on participants, with outcomes regarding physical activity and/or sedentary behaviour during lockdown/restriction measures, and with comparisons for these outcomes to a time when no such measures were in place. Where appropriate, results from included studies will be pooled and effect estimates will be presented in random effects meta-analyses. To the best of our knowledge, this will be the first systematic review to evaluate one complete year of published data on the impact of COVID-19-related lockdown/restriction measures on physical activity and sedentary behaviour. Thus, this systematic review and meta-analysis will constitute the most up-to-date synthesis of published evidence on any such documented changes, and so will comprehensively inform clinical practitioners, public health agencies, researchers, policymakers and the general public regarding the effects of lockdown/restriction measures on both physical activity and sedentary behaviour.
    • Exercise-induced muscle damage and recovery in young and middle-aged males with different resistance training experience

      Fernandes, John; Lamb, Kevin L.; Twist, Craig (MDPI, 2019-05-29)
      This study compared the time course of recovery after a squatting exercise in trained young (YG; n = 9; age 22.3 ± 1.7 years) and trained (MT; n = 9; 39.9 ± 6.2 years) and untrained (MU; n = 9; age 44.4 ± 6.3 years) middle-aged males. Before and at 24 and 72 h after 10 × 10 squats at 60% one-repetition maximum (1RM), participants provided measurements of perceived muscle soreness (VAS), creatine kinase (CK), maximal voluntary contraction (MVC), voluntary activation (VA), and resting doublet force of the knee extensors and squatting peak power at 20% and 80% 1RM. When compared to the YG males, the MT experienced likely and very likely moderate decrements in MVC, resting doublet force, and peak power at 20% and 80% 1RM accompanied by unclear differences in VAS, CK, and VA after the squatting exercise. MU males, compared to MT, experienced greater alterations in peak power at 20% and 80% 1RM and VAS. Alterations in CK, MVC, VA, and resting doublet force were unclear at all time-points between the middle-aged groups. Middle-aged males experienced greater symptoms of muscle damage and an impaired recovery profile than young resistance trained males. Moreover, regardless of resistance training experience, middle-aged males are subject to similar symptoms after muscle-damaging lower-body exercise.
    • From Surveillance to Intervention: Overview and Baseline Findings for the Active City of Liverpool Active Schools and SportsLinx (A-CLASS) Project

      McWhannell, Nicola; Foweather, Lawrence; Graves, Lee; Henaghan, Jayne; Ridgers, Nicola D.; Stratton, Gareth; University of Chester; Liverpool John Moores University, Laude Lady Elizabeth Junior School, Deakin University, Swansea University (MDPI, 2018-03-23)
      This paper outlines the implementation of a programme of work that started with the development of a population-level children’s health, fitness and lifestyle study in 1996 (SportsLinx) leading to selected interventions one of which is described in detail: the Active City of Liverpool, Active Schools and SportsLinx (A-CLASS) Project. The A-CLASS Project aimed to quantify the effectiveness of structured and unstructured physical activity (PA) programmes on children’s PA, fitness, body composition, bone health, cardiac and vascular structures, fundamental movement skills, physical self-perception and self-esteem. The study was a four-arm parallel-group school-based cluster randomised controlled trial (clinical trials no. NCT02963805), and compared different exposure groups: a high intensity PA (HIPA) group, a fundamental movement skill (FMS) group, a PA signposting (PASS) group and a control group, in a two-schools-per-condition design. Baseline findings indicate that children’s fundamental movement skill competence levels are low-to-moderate, yet these skills are inversely associated with percentage body fat. Outcomes of this project will make an important contribution to the design and implementation of children’s PA promotion initiatives.
    • Influence of Playing Standard on Upper- and Lower-Body Strength, Power, and Velocity Characteristics of Elite Rugby League Players

      Fernandes, John; Daniels, Matthew; Myler, Liam; Twist, Craig (MDPI, 2019-04-17)
      Background: To compare load–velocity and load–power relationships among first grade (n = 26, age 22.9 ± 4.3 years), academy (n = 23, age 17.1 ± 1.0 years), and scholarship (n = 16, age 15.4 ± 0.5 years) Super League rugby league players. Methods: Participants completed assessments of maximal upper- and lower-body strength (1RM) and peak velocity and power at 20, 40, 60, and 80 kg during bench press and squat exercises, in a randomised order. Results: Bench press and squat 1RM were highest for first grade players compared with other standards (effect size (ES) = −0.43 to −3.18). Peak velocities during bench and squat were greater in the higher playing standards (ES = −0.39 to −3.72 range), except for the squat at 20 and 40 kg. Peak power was higher in the better playing standards for all loads and exercises. For all three groups, velocity was correlated to optimal bench press power (r = 0.514 to 0.766), but only 1RM was related to optimal power (r = 0.635) in the scholarship players. Only squat 1RM in the academy was related to optimal squat power (r = 0.505). Conclusions: Peak velocity and power are key physical qualities to be developed that enable progression from junior elite rugby league to first grade level. Resistance training should emphasise both maximal strength and velocity components, in order to optimise upper- and lower-body power in professional rugby league players.
    • Low body fat does not influence recovery after muscle-damaging lower-limb plyometrics in young male team sport athletes

      Fernandes, John; Lamb, Kevin; Twist, Craig; University of Chester
      Aim: This study assessed the influence of fat mass to fat-free mass ratio (FM:FFM) on recovery from plyometric exercise. Method: After assessment of body composition, 20 male team sport players (age 20.7 1.1 years; body mass 77.1 11.5 kg) were divided into low- (n = 10; 0.11 0.03) and normal- (n = 10; 0.27 0.09) fat groups based on FM:FFM ratio. Thereafter, participants completed measurements of knee extensor torque at 60 and 240 s􀀀1, countermovement jump flight time, plasma creatine kinase (CK) activity and perceived muscle soreness (VAS) before and at 0, 24 and 48 h after 10 10 maximal plyometric vertical jumps. Results: Evidence of muscle damage was confirmed by alterations in VAS, peak torque at 60 and 240 s􀀀1 and flight time at 0, 24 and 48 h after plyometric exercise (P < 0.05). CK was increased at 0 and 24 h (P < 0.05) but returned to baseline values by 48 h. No time by group e ects were observed for any of the dependent variables (P > 0.05). Conclusion: The current findings indicate that while muscle damage was present after plyometric exercise, the magnitude was similar across the two body composition groups. Applied practitioners can allow for a similar recovery time after plyometric exercise in those with low and normal body fat.