The manifestations of fatigue during fast bowling in cricket were systematically evaluated using subjective reports by cricket experts and quantitative data published from scientific studies. Narratives by international players and team physiotherapists were sourced from the Internet using criteria for opinion-based evidence. Research articles were evaluated for high-level fast bowlers who delivered 5- to 12-over spells with at least 1 quantitative fatigue measure. Anecdotes indicate that a long-term loss of bowling speed, tiredness, mental fatigue, and soreness occur. Scientific research shows that ball-release speed, bowling accuracy, bowling action (technique), run-up speed, and leg-muscle power are generally well maintained during bowling simulations. However, bowlers displaying excessive shoulder counterrotation toward the end of a spell also show a fall in accuracy. A single notable study involving bowling on 2 successive days in the heat showed reduced ball-release speed (–4.4 km/h), run-up speed (–1.3 km/h), and accuracy. Moderate to high ratings of perceived exertion transpire with simulations and match play (6.5–7.5 Borg CR-10 scale). Changes of blood lactate, pH, glucose, and core temperature appear insufficient to impair muscle function, although several potential physiological fatigue factors have not been investigated. The limited empirical evidence for bowling-induced fatigue appears to oppose player viewpoints and indicates a paradox. However, this may not be the case since bowling simulations resemble the shorter formats of the game but not multiday (test match) cricket or the influence of an arduous season, and comments of tiredness, mental fatigue, and soreness signify phenomena different from what scientists measure as fatigue.
Ed Maunder, Andrew E. Kilding and Simeon P. Cairns
Ed Maunder, Paul B. Laursen and Andrew E. Kilding
To compare the physiological and performance effects of ad libitum cold-fluid (CF) and ice-slurry (IS) ingestion on cycling time-trial (TT) performance in the heat.
Seven well-trained male triathletes and cyclists completed 2 maximaleffort 40-km cycling TTs in hot (35°C) and humid (60% relative humidity) conditions. In randomized order, participants ingested CF or IS (initial temperatures 4°C and –1°C, respectively) ad libitum during exercise. At each 5-km interval, time elapsed, power output, rectal and skin temperature, heart rate, and perceptual measures were recorded. The actual CF and IS temperatures during the 40-km TT were determined post hoc.
Performance time (2.5% ± 2.6%, ES = 0.27) and mean power (–2.2% ± 3.2%, ES = –0.15) were likely worse in the IS trial. Differences in thermoregulatory and cardiovascular measures were largely unclear between trials, while feeling state was worse in the later stages of the IS trial (ES = –0.31 to –0.95). Fluid-ingestion volume was very likely lower in the IS trial (–29.7% ± 19.4%, ES = –0.97). The temperatures of CF and IS increased by 0.37°C/min and 0.02°C/min, respectively, over the mean TT duration.
Ad libitum ingestion of CF resulted in improved 40-km cycling TT performance compared with IS. Participants chose greater fluid-ingestion rates in the CF trial than in the IS trial and had improved feeling state. These findings suggest that ad libitum CF ingestion is preferable to IS during cycling TTs under conditions of environmental heat stress.
Ed Maunder, Andrew E. Kilding, Christopher J. Stevens and Daniel J. Plews
A common practice amongst endurance athletes is to purposefully train in hot environments during a ‘heat stress camp’. However, combined exercise-heat stress poses threats to athlete wellbeing, and therefore heat stress training has the potential to induce maladaptation. This case study describes the monitoring strategies used in a successful three-week heat stress camp undertaken by two elite Ironman triathletes, namely resting heart rate variability, self-report wellbeing, and careful prescription of training based on previously collected physiological data. Despite the added heat stress, training volume very likely increased in both athletes, and training load very likely increased in one of the athletes, whilst resting HRV and self-report wellbeing were maintained. There was also some evidence of favourable metabolic changes during routine laboratory testing following the camp. We therefore recommend that practitioners working with endurance athletes embarking on a heat stress training camp consider using the simple strategies employed in the present case study to reduce the risk of maladaptation and non-functional overreaching.