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Julia Zakrzewski and Keith Tolfrey
Consensus on the exercise protocol used to measure Fatmax (exercise intensity corresponding to maximum fat oxidation (MFO)) in children has not been reached. The present study compared Fatmax estimated using the 3 min incremental cycling protocol (3-INC) and a protocol consisting of several 10 min constant work rate exercise bouts (10-CWR) in 26 prepubertal children. Group Fatmax values were the same for 3-INC and 10-CWR (55% VO2peak) and 95% limits of agreement (LoA) were ± 7% VO2peak. Group MFO values were similar between protocols, although 95% LoA were -94 to 113 mg·min−1. While 3-INC provides a valid estimation of Fatmax compared with 10-CWR, caution should be exercised when estimating MFO in prepubertal children.
Rachel Massie, James Smallcombe, and Keith Tolfrey
Purpose: Chronic exercise programs can induce adaptive compensatory behavioral responses through increased energy intake (EI) and/or decreased free-living physical activity in adults. These responses can negate the benefits of an exercise-induced energy deficit; however, it is unclear whether young people experience similar responses. This study examined whether exercise-induced compensation occurs in adolescent girls.
Methods: Twenty-three adolescent girls, heterogeneous for weight status, completed the study. Eleven adolescent girls aged 13 years completed a 12-week supervised exercise intervention (EX). Twelve body size–matched girls comprised the nonexercise control group (CON). Body composition, EI, free-living energy expenditure (EE), and peak oxygen uptake (
Joey C. Eisenmann and Keith Tolfrey
Victoria L. Goosey-Tolfrey, Nicholas J. Diaper, Jeanette Crosland, and Keith Tolfrey
Wheelchair tennis players, competing in hot and humid environments, are faced with an increased risk of heat-related illness and impaired performance. This study examined the effects of head and neck cooling garments on perceptions of exertion (RPE), thermal sensation (TS), and water consumption during wheelchair exercise at 30.4 ± 0.6°C.
Eight highly trained wheelchair tennis players (1 amputee and 7 spinal cord injured) completed two 60-min, intermittent sprint trials; once with cooling (COOL) and once without cooling (CON) in a balanced cross-over design. Players could drink water ad libitum at five predetermined intervals during each trial. Heart rate, blood lactate concentration, peak speed, TS, and RPE were recorded during the trials. Body mass and water consumption were measured before and after each trial.
Water consumption was lower in COOL compared with CON (700 ± 393 mL vs. 1198 ± 675 mL respectively; P = 0.042). Trends in data suggested lower RPE and TS under COOL conditions (N.S.). Total sweat losses ranged from 200 to 1300 mL; this equated to ~1% dehydration after water consumption had been accounted for when averaged across all trials. The ad libitum drinking volumes matched and, in some cases, were greater than the total sweat losses.
These results suggest that there is a counterproductive effect of head and neck cooling garments on water consumption. However, despite consuming volumes of water at least equivalent to total sweat loss, changes in body mass suggest an incidence of mild dehydration during wheelchair tennis in the heat.
Keith Tolfrey, Julia K. Zakrzewski-Fruer, and James Smallcombe
Three publications were selected based on the strength of the research questions, but also because they represent different research designs that are used with varying degrees of frequency in the pediatric literature. The first, a prospective, longitudinal cohort observation study from 7 to 16 years with girls and boys reports an intrinsic reduction in absolute resting energy expenditure after adjustment for lean mass, fat mass, and biological maturity. The authors suggest this could be related to evolutionary energy conservation, but may be problematic now that food energy availability is so abundant. The second focuses on the effect of acute exercise on neutrophil reactive oxygen species production and inflammatory markers in independent groups of healthy boys and men. The authors suggested the boys experienced a “sensitized” neutrophil response stimulated by the exercise bout compared with the men; moreover, the findings provided information necessary to design future trials in this important field. In the final study, a dose-response design was used to examine titrated doses of high intensity interval training on cardiometabolic outcomes in adolescent boys. While the authors were unable to identify a recognizable dose-response relationship, there are several design strengths in this study, which was probably underpowered.
Ben T. Stephenson, Sven P. Hoekstra, Keith Tolfrey, and Victoria L. Goosey-Tolfrey
Purpose: Paratriathletes may display impairments in autonomic (sudomotor and/or vasomotor function) or behavioral (drinking and/or pacing of effort) thermoregulation. As such, this study aimed to describe the thermoregulatory profile of athletes competing in the heat. Methods: Core temperature (T c) was recorded at 30-second intervals in 28 mixed-impairment paratriathletes during competition in a hot environment (air temperature = 33°C, relative humidity = 35%–41%, and water temperature = 25°C–27°C), via an ingestible temperature sensor (BodyCap e-Celsius). Furthermore, in a subset of 9 athletes, skin temperature was measured. Athletes’ wetsuit use was noted while heat illness symptoms were self-reported postrace. Results: In total, 22 athletes displayed a T c ≥ 39.5°C with 8 athletes ≥40.0°C. There were increases across the average T c for swim, bike, and run sections (P ≤ .016). There was no change in skin temperature during the race (P ≥ .086). Visually impaired athletes displayed a significantly greater T c during the run section than athletes in a wheelchair (P ≤ .021). Athletes wearing a wetsuit (57% athletes) had a greater T c when swimming (P ≤ .032), whereas those reporting heat illness symptoms (57% athletes) displayed a greater T c at various time points (P ≤ .046). Conclusions: Paratriathletes face significant thermal strain during competition in the heat, as evidenced by high T c, relative to previous research in able-bodied athletes and a high incidence of self-reported heat illness symptomatology. Differences in the T c profile exist depending on athletes’ race category and wetsuit use.
Ben T. Stephenson, Christof A. Leicht, Keith Tolfrey, and Victoria L. Goosey-Tolfrey
Purpose: In able-bodied athletes, several hormonal, immunological, and psychological parameters are commonly assessed in response to intensified training due to their potential relationship to acute fatigue and training/nontraining stress. This has yet to be studied in Paralympic athletes. Methods: A total of 10 elite paratriathletes were studied for 5 wk around a 14-d overseas training camp whereby training load was 137% of precamp levels. Athletes provided 6 saliva samples (1 precamp, 4 during camp, and 1 postcamp) for cortisol, testosterone, and secretory immunoglobulin A; weekly psychological questionnaires (Profile of Mood State [POMS] and Recovery-Stress Questionnaire for Athletes [RESTQ-Sport]); and daily resting heart rate and subjective wellness measures including sleep quality and quantity. Results: There was no significant change in salivary cortisol, testosterone, cortisol:testosterone ratio, or secretory immunoglobulin A during intensified training (P ≥ .090). Likewise, there was no meaningful change in resting heart rate or subjective wellness measures (P ≥ .079). Subjective sleep quality and quantity increased during intensified training (P ≤ .003). There was no significant effect on any POMS subscale other than lower anger (P = .049), whereas there was greater general recovery and lower sport and general stress from RESTQ-Sport (P ≤ .015). Conclusions: There was little to no change in parameters commonly associated with the fatigued state, which may relate to the training-camp setting minimizing external life stresses and the careful management of training loads from coaches. This is the first evidence of such responses in Paralympic athletes.
Ben T. Stephenson, Eleanor Hynes, Christof A. Leicht, Keith Tolfrey, and Victoria L. Goosey-Tolfrey
Purpose: To gain an exploratory insight into the relation between training load (TL), salivary secretory immunoglobulin A (sIgA), and upper respiratory tract illness (URI) in elite paratriathletes. Methods: Seven paratriathletes were recruited. Athletes provided weekly saliva samples for the measurement of sIgA over 23 consecutive weeks (February to July) and a further 11 consecutive weeks (November to January). sIgA was compared to individuals’ weekly training duration, external TL, and internal TL, using time spent in predetermined heart-rate zones. Correlations were assessed via regression analyses. URI was quantified via weekly self-report symptom questionnaire. Results: There was a significant negative relation between athletes’ individual weekly training duration and sIgA secretion rate (P = .028), with changes in training duration accounting for 12.7% of the variance (quartiles: 0.2%, 19.2%). There was, however, no significant relation between external or internal TL and sIgA parameters (P ≥ .104). There was no significant difference in sIgA when URI was present or not (101% vs 118% healthy median concentration; P ≥ .225); likewise, there was no difference in sIgA when URI occurred within 2 wk of sampling or not (83% vs 125% healthy median concentration; P ≥ .120). Conclusions: Paratriathletes’ weekly training duration significantly affects sIgA secretion rate, yet the authors did not find a relation between external or internal TL and sIgA parameters. Furthermore, it was not possible to detect any link between sIgA and URI occurrence, which throws into question the potential of using sIgA as a monitoring tool for early detection of illness.