Rhys Thatcher

A modified TRIMP to quantify the in-season training load of team sport players

Abstract The aims of the study were to modify the training impulse (TRIMP) method of quantifying training load for use with intermittent team sports, and to examine the relationship between this modified TRIMP (TRIMPMOD) and changes in the physiological profile of team sport players during a competitive season. Eight male field hockey players, participating in the English Premier Division, took part in the study (mean±s: age 26±4 years, body mass 80.8±5.2 kg, stature 1.82±0.04 m). Participants performed three treadmill exercise tests at the start of the competitive season and mid-season: a submaximal test to establish the treadmill speed at a blood lactate concentration of 4 mmol · l−1; a maximal incremental test to determine maximal oxygen uptake ([Vdot]O2max) and peak running speed; and an all-out constant-load test to determine time to exhaustion. Heart rate was recorded during all training sessions and match-play, from which TRIMPMOD was calculated. Mean weekly TRIMPMOD was correlated with the change in [Vdot]O2max and treadmill speed at a blood lactate concentration of 4 mmol · l−1 from the start of to mid-season (P<0.05). The results suggest that TRIMPMOD is a means of quantifying training load in team sports and can be used to prescribe training for the maintenance or improvement of aerobic fitness during the competitive season.

Influence of blood donation on O2 uptake on-kinetics, peak O2 uptake and time to exhaustion during severe-intensity cycle exercise in humans

We hypothesized that the reduction of O2‐carrying capacity caused by the withdrawal of ∼450 ml blood would result in slower phase II O2 uptake kinetics, a lower and a reduced time to exhaustion during severe‐intensity cycle exercise. Eleven healthy subjects (mean ±s.d. age 23 ± 6 years, body mass 77.2 ± 11.0 kg) completed ‘step’ exercise tests from unloaded cycling to a severe‐intensity work rate (80% of the difference between the predetermined gas exchange threshold and the ) on two occasions before, and 24 h following, the voluntary donation of ∼450 ml blood. Oxygen uptake was measured breath‐by‐breath, and kinetics estimated using non‐linear regression techniques. The blood withdrawal resulted in a significant reduction in haemoglobin concentration (pre: 15.4 ± 0.9 versus post: 14.7 ± 1.3 g dl−1; 95% confidence limits (CL): −0.04, −1.38) and haematocrit (pre: 44 ± 2 versus post: 41 ± 3%; 95% CL: −1.3, −5.1). Compared to the control condition, blood withdrawal resulted in significant reductions in (pre: 3.79 ± 0.64 versus post: 3.64 ± 0.61 l min−1; 95% CL: −0.04, − 0.27) and time to exhaustion (pre: 375 ± 129 versus post: 321 ± 99 s; 95% CL: −24, −85). However, the kinetic parameters of the fundamental response, including the phase II time constant (pre: 29 ± 8 versus post: 30 ± 6 s; 95% CL: 5, −3), were not altered by blood withdrawal. The magnitude of the slow component was significantly reduced following blood donation owing to the lower attained. We conclude that a reduction in blood O2‐carrying capacity, achieved through the withdrawal of ∼450 ml blood, results in a significant reduction in and exercise tolerance but has no effect on the fundamental phase of the on‐kinetics during severe‐intensity exercise.

Effects of Instructional and Motivational Self-talk on the Vertical Jump

Tod, DA, Thatcher, R, McGuigan, M, and Thatcher, J. Effects of instructional and motivational self-talk on the vertical jump. J Strength Cond Res 23(1): 196-202, 2009-The purpose of this study was to investigate the effects of instructional and motivational self-talk on performance and the kinematics of the vertical jump. After completing a 10-minute warm-up on a stationary bike, 12 men (mean ± SD; 20.8 ± 3.0 years, 77.8 ± 13.5 kg, 1.78 ± 0.07 m) and 12 women (22.1 ± 5.8 years, 62.6 ± 6.7 kg, 1.65 ± 0.05 m) performed 4 vertical jumps, 3 minutes apart, on a force plate set at a 1000-Hz sampling frequency. Before each trial, participants engaged in 1 of 4 counterbalanced interventions, verbalized out loud, which included motivational self-talk, instructional self-talk, neutral self-talk, or no instruction. One-way analysis of variance with repeated measures, followed by paired t-tests with a Bonferroni adjustment, were used to analyze data. Both instructional (0.415 m) and motivational (0.414 m) self-talk led to greater center-of-mass displacement than neutral self-talk (0.403 m, p = 0.001 and 0.003, respectively, alpha set at 0.008). Both instructional (263.9 N·s) and motivational self-talk (261.2 N·s) led to greater impulse than neutral self-talk (254.1 N·s, p = 0.005 and 0.004, respectively, alpha set at 0.025). Both instructional self-talk (582.6°·s−1) and motivational self-talk (592.3°·s−1) led to quicker angular rotation about the knee than neutral self-talk (565.8°·s−1, p = 0.001 and 0.018, respectively, alpha set at 0.025). These results may indicate that self-talk leads to greater angular velocity about the knee, thus generating greater impulse and increased jump height-a conjecture that needs empirical testing. Self-talk may contribute to improved performance in sports requiring power-based skills.

Effects of bovine colostrum supplementation on upper respiratory illness in active males.

Bovine colostrum (COL) has been advocated as a nutritional countermeasure to exercise-induced immune dysfunction and increased risk of upper respiratory illness (URI) in athletic populations, however, the mechanisms remain unclear. During winter months, under double-blind procedures, 53 males (mean training load±SD, 50.5±28.9 MET-hweek(-1)) were randomized to daily supplementation of 20g of COL (N=25) or an isoenergetic/isomacronutrient placebo (PLA) (N=28) for 12weeks. Venous blood was collected at baseline and at 12weeks and unstimulated saliva samples at 4 weeks intervals. There was a significantly lower proportion of URI days and number of URI episodes with COL compared to PLA over the 12weeks (p<0.05). There was no effect of COL on in vitro neutrophil oxidative burst, salivary secretory IgA or salivary antimicrobial peptides (p>0.05), which does not support previously suggested mechanisms. In a subset of participants (COL=14, PLA=17), real-time quantitative PCR, targeting the 16S rRNA gene showed there was an increase in salivary bacterial load over the 12 weeks period with PLA (p<0.05) which was not as evident with COL. Discriminant function analysis of outputs received from serum metabolomics showed changes across time but not between groups. This is the first study to demonstrate that COL limits the increased salivary bacterial load in physically active males during the winter months which may provide a novel mechanism of immune-modulation with COL and a relevant marker of in vivo (innate) immunity and risk of URI.

Zinc carnosine works with bovine colostrum in truncating heavy exercise–induced increase in gut permeability in healthy volunteers

BACKGROUND Heavy exercise causes gut symptoms and, in extreme cases, heat stroke that is due to the increased intestinal permeability of luminal toxins. OBJECTIVE We examined whether zinc carnosine (ZnC), a health-food product taken alone or in combination with bovine colostrum (a natural source of growth factors), would moderate such effects. DESIGN Eight volunteers completed a 4-arm, double-blind, placebo-controlled crossover protocol (14 d of placebo, ZnC, colostrum, or ZnC plus colostrum) before undertaking standardized exercise 2 and 14 d after the start of treatment. Changes in epithelial resistance, apoptosis signaling molecules, and tight junction (TJ) protein phosphorylation in response to a 2°C rise in body temperature were determined with the use of Caco-2 and HT29 intestinal cells. RESULTS Body temperature increased 2°C, and gut permeability (5-h urinary lactulose:rhamnose ratios) increased 3-fold after exercise (from 0.32 ± 0.016 baseline to 1.0 ± 0.017 at 14 d; P < 0.01). ZnC or colostrum truncated the rise by 70% after 14 d of treatment. The combination treatment gave an additional benefit, and truncated exercise induced increase at 2 d (30% reduction; P < 0.01). A 2°C temperature rise in in vitro studies caused the doubling of apoptosis and reduced epithelial resistance 3-4-fold. ZnC or colostrum truncated these effects (35-50%) with the greatest response seen with the combination treatment (all P < 0.01). Mechanisms of action included increasing heat shock protein 70 and truncating temperature-induced changes in B cell leukemia/lymphoma-2 associated X protein α and B cell lymphoma 2. ZnC also increased total occludin and reduced phosphorylated tyrosine claudin, phosphorylated tyrosine occludin, and phosphorylated serine occludin, thereby enhancing the TJ formation and stabilization. CONCLUSION ZnC, taken alone or with colostrum, increased epithelial resistance and the TJ structure and may have value for athletes and in the prevention of heat stroke in military personnel. This trial was registered at www.isrctn.com as ISRCTN51159138.

Failure of oral tyrosine supplementation to improve exercise performance in the heat

PURPOSE Acute oral tyrosine administration has been associated with increased constant-load, submaximal exercise capacity in the heat. This study sought to determine whether self-paced exercise performance in the heat is enhanced with the same tyrosine dosage. METHODS After familiarization, seven male endurance-trained volunteers, unacclimated to exercise in the heat, performed two experimental trials in 30°C (60% relative humidity) in a crossover fashion separated by at least 7 d. Subjects ingested 150 mg·kg(-1) body mass tyrosine (TYR) or an isocaloric quantity of whey powder (PLA) in 500 mL of sugar-free flavored water in a randomized, double-blind fashion. Sixty minutes after drink ingestion, the subjects cycled for 60 min at 57% ± 4% peak oxygen uptake (VO2peak) and then performed a simulated cycling time trial requiring completion of an individualized target work quantity (393.1 ± 39.8 kJ). RESULTS The ratio of plasma tyrosine plus phenylalanine (tyrosine precursor) to amino acids competing for brain uptake (free-tryptophan, leucine, isoleucine, valine, methionine, threonine, and lysine) increased 2.5-fold from rest in TYR and remained elevated throughout exercise (P < 0.001), whereas it declined in PLA from rest to preexercise (P = 0.004). Time-trial power output (P = 0.869) and performance (34.8 ± 6.5 and 35.2 ± 8.3 min in TYR and PLA, respectively; P = 0.4167) were similar between trials. Thermal sensation (P > 0.05), RPE (P > 0.05), core temperature (P = 0.860), skin temperature (P = 0.822), and heart rate (P = 0.314) did not differ between trials. CONCLUSIONS These data indicate that acute tyrosine administration did not influence self-paced endurance exercise performance in the heat. Plasma tyrosine availability is apparently not a key determinant of fatigue processes under these conditions.

Perceptual and cognitive responses during exercise: Relationships with metamotivational state and dominance

Abstract In this study, we examined ratings of perceived exertion (RPE) and attentional focus during exercise in relation to telic and paratelic metamotivational dominance and state. Thirty regular exercisers (11 females, 19 males), of whom 10 were telic dominant (mean Paratelic Dominance Scale score=6.2±2.9), 10 paratelic dominant (mean PDS score=23.8±1.4), and 10 non-dominant (mean PDS score=15.4±0.7) completed two exercise trials. In the first trial, the participants completed a maximal ramped exercise test on a motorized treadmill to determine their gas exchange threshold (the speed at which determined exercise intensity of the subsequent trial). Throughout the second trial (a 30-min treadmill run), the participants reported their metamotivational state, RPE, and attentional focus (associative or dissociative) at 5-min intervals. Heart rate was recorded at 3, 8, 13, 18, 23, and 28 min and expired air was analysed for oxygen consumption (VO2) between 1–3, 6–8, 11–13, 16–18, 21–23, and 26–28 min. There was no main effect of dominance or dominance×time interaction on any variables (P >0.05). Oxygen consumption did not differ between states but RPE was higher in the telic than paratelic state at 25 and 30 min (t 28=2.87, P <0.05; t 26.77=3.88, P <0.05, respectively). Attentional focus was more associative in the telic than paratelic state at 20, 25, and 30 min (t 28=− 3.73, P <0.05; t 28=− 4.85, P <0.01; t 28=− 5.15, P <0.05, respectively) and heart rate was higher at 23 min in the telic state (t 27=3.40, P <0.05). During the latter stages of exercise, the telic metamotivational state, not dominance, was related to a more associative attentional focus and higher RPE. Our results support the use of reversal theory (Apter, 2001) to understand perceptual and cognitive responses during aerobic exercise, but an experimental design in which state is manipulated is needed to examine the effects of metamotivational dominance and state on perceptual and cognitive responses.

Stress responses during aerobic exercise in relation to motivational dominance and state

Abstract We examined the hypothesis that congruence between motivational dominance and state results in optimal psychological responses and performance during exercise. Twenty participants (10 telic dominant and 10 paratelic dominant) rated their stress at 5 min intervals as they cycled on an ergometer at gas exchange threshold for 30 min in both telic and paratelic state manipulated conditions. Participants then performed a test to exhaustion at a resistance equivalent to 110% of [Vdot]O2max. The hypothesized interaction between condition and dominance was significant for internal tension stress, as paratelic dominants were more stressed than telic dominants when exercising in the telic state and telic dominants were more stressed than paratelic dominants when exercising in the paratelic state. Similarly, the condition×dominance interaction for internal stress discrepancy was significant, as paratelic dominants reported greater internal stress discrepancy exercising in the telic compared with the paratelic state. Findings are discussed in relation to the application of reversal theory for understanding stress responses during aerobic exercise.

Metamotivational state and dominance : Links with EMG gradients during isokinetic leg extension and a test of the misfit effect

Abstract Although electromyographic (EMG) gradients have been observed in passive musculature during perceptual motor tasks, it is unclear whether this is related to metamotivational state or dominance. In addition, a misfit effect has been suggested whereby individuals report negative psychological responses when metamotivational state and dominance do not match. Research examining these phenomena within an exercise context is limited; therefore, this study used a reversal theory (Apter, 2001) framework to examine two hypotheses. The first hypothesis was that an EMG gradient would be observed when individuals performed isokinetic leg extensions in a telic metamotivational state, regardless of telic or paratelic metamotivational dominance. Second, it was hypothesizsed that telic-dominant individuals and paratelic-dominant individuals would perform better on this task when in the telic and paratelic state, respectively. Altogether, 14 telic-dominant and 12 paratelic-dominant individuals performed 100 self-paced isokinetic leg extensions at a rate of 90° · s−1 in both telic and paratelic state manipulated conditions. Regardless of state, an EMG gradient was observed in telic-dominant individuals but not in paratelic-dominant individuals. Paratelic-dominant individuals performed better in the paratelic than the telic state condition, whereas in the telic state condition, telic-dominant individuals performed better than paratelic-dominant individuals. Findings add to the debate concerning the role of telic metamotivational state and dominance in the production of EMG gradients. Performance data support the misfit effect that outcomes are more positive when metamotivational state and dominance are congruent. Suggestions for research developments in this area are offered, as are tentative implications for applied practice.

Influence of 4 weeks of bovine colostrum supplementation on neutrophil and mucosal immune responses to prolonged cycling

Bovine colostrum (COL) has been advocated as a nutritional countermeasure to exercise‐induced immune dysfunction. The aims of this study were to identify the effects of 4 weeks of COL supplementation on neutrophil responses and mucosal immunity following prolonged exercise. In a randomized double‐blind, parallel group design, participants [age 28 ± 8 years; body mass 79 ± 7 kg; height 182 ± 6 cm; maximal oxygen uptake ( V ˙ O 2 m a x ) 55 ± 9 mL/kg/min] were assigned to 20 g per day of COL (n = 10) or an isoenergetic/isomacronutrient placebo (PLA; n = 10) for 4 weeks. Venous blood and unstimulated saliva samples were obtained before and after 2.5 h of cycling at 15% Δ (∼55–60% V ˙ O 2 m a x ). A significantly greater formyl‐methionyl‐leucyl phenylalanine‐stimulated oxidative burst was observed in the COL group compared with PLA group (P < 0.05) and a trend toward a time × group interaction (P = 0.06). However, there was no effect of COL on leukocyte trafficking, phorbol‐12‐myristate‐13‐acetate‐stimulated oxidative burst, bacterial‐stimulated neutrophil degranulation, salivary secretory IgA, lactoferrin or lysozyme (P > 0.05). These findings provide further evidence of the beneficial effects of COL on receptor‐mediated stimulation of neutrophil oxidative burst in a model of exercise‐induced immune dysfunction.