• Daily-running exercise may induce incomplete energy intake compensation: a 7-day crossover trial

      Hough, John; Esh, Christopher John; Mackie, Paul Ian; Stensel, David J.; Zakrzewski-Fruer, Julia K.; University of Bedfordshire (Canadian Science Publishing, 2019-12-13)
      Understanding daily-exercise effects on energy balance is important. This study examined the effects of seven days of imposed exercise (EX) and no exercise (N-EX) on free-living energy intake (EI) and physical activity energy expenditure (PAEE) in nine men. Free-living EI was higher in EX compared with N-EX. Total and vigorous PAEE were higher, with PAEE in sedentary activities lower, during EX compared with N-EX. Daily-running (for 7 days) induced EI compensation of ~60% exercise-induced EE.
    • Determinants of club head speed in PGA professional golfers

      Lewis, Adam L,; Ward, Nicholas; Bishop, Chris; Maloney, Sean J.; Turner, Anthony; ; Sandy Lodge golf club; England Golf; Middlesex University; University of Bedfordshire (NSCA National Strength and Conditioning Association, 2016-08-31)
      Turner, AN. Determinants of club head speed in PGA professional golfers. J Strength Cond Res 30(8): 2266-2270, 2016 - Club head speed (CHS) has been significantly correlated with golf performance, but only in amateurs. The purpose of this study therefore, was to investigate the relationship between field-based measures of strength and power with CHS in Professional Golfers Association (PGA) professional golfers, and further determine differences between age groups. A correlation design was used to test relationships between squat jump (SJ), seated medicine ball throw (SMBT), rotational medicine ball throw (RMBT), and CHS. Twenty participants volunteered to take part in the study (age, 31.95 ± 8.7 years; height, 182.75 ± 6.88 cm; mass, 90.47 ± 15.6 kg). Intraclass correlation coefficients reported high reliability for performance variables (r 0.85-0.95). Significant correlations (p < 0.01) were found between CHS and SJ (r 0.817) and SMBT (r 0.706), but not RMBT (r 0.572). A stepwise linear regression analysis identified that SJ and SMBT explained 74% of the variance in CHS. When dividing the sample based on age, professionals <30 years (n 10; 25.6 ± 2.9 years) displayed significantly (p ≤ 0.05) higher CHS and SJ height compared with professionals >30 (n 10; 39.7 ± 5.5 years). Correlations to CHS for <30 were significant for SJ (r 0.801) and SMBT (r 0.643), but nonsignificant for RMBT. Those >30 had significant correlations to CHS not only in SMBT (r 0.881) and SJ (r 0.729), but also in RMBT (r 0.642). The results of this study suggest that SJ and SMBT have the largest contribution to CHS in PGA professional golfers. When comparing age groups, it appears that younger golfers (<30 years) utilize more leg strength whereas older golfers (>30 years) utilize more upper body strength. Results suggest that strength-based leg exercises and power-based chest exercises may improve CHS in professional golfers.
    • Determinants of weekly sitting time: construct validation of an initial COM-B model and comparison of its predictive validity with the Theory of Planned Behaviour

      Howlett, Neil; Schulz, Joerg; Trivedi, Daksha; Troop, Nicholas A.; Chater, Angel M.; University of Hertfordshire; University of Bedfordshire (Taylor & Francis, 2020-05-14)
      Objective: In relation to sitting behaviour, to investigate which theoretical domains best formed the Capability, Opportunity, and Motivation constructs of the COM-B, and compare the predictive validity to the Theory of Planned Behaviour (TPB), taking habit strength into consideration. Design: Using a prospective design, 186 adults completed measures capturing domains from the Theoretical Domains Framework for the three COM-B constructs, and habit strength, which were examined using a formative measurement model. Predictive validity was then compared to the TPB. Main Outcome Measures: Self-reported sitting behaviour. Results: Self-monitoring (behavioural regulation domain) formed Capability; subjective norm (social influences domain) formed Opportunity; intention (intentions domain), positive affect (emotion domain), and perceived behavioural control (beliefs about capabilities domain), formed Motivation. The COM-B strongly predicted sitting behaviour (27% variance explained), with Capability, Opportunity, and habit strength as key drivers. The TPB explained a large amount of variance (23%) in sitting behaviour, with intention and habit strength as key drivers. Conclusions: The behavioural regulation domain of Capability, the social influences domain of Opportunity, and habit strength were important drivers of sitting behaviour, with comparable variance predicted in the COM-B and TPB. Future research should consider this approach to conceptualise the COM-B for specific populations and behaviours.
    • Development of a sedentary behaviour workplace intervention for police staff using the behaviour change wheel

      Brierley, Marsha L.; Chater, Angel M.; Smith, Lindsey Rachel; Bailey, Daniel Paul; University of Bedfordshire (2019-11-01)
    • Do stiffness and asymmetries predict change of direction performance?

      Maloney, Sean J.; Richards, Joanna C.; Nixon, Daniel G.D.; Harvey, Lewis J.; Fletcher, Iain M.; University of Bedfordshire (TAYLOR & FRANCIS LTD, 2016-04-30)
      Change of direction speed (CODS) underpins performance in a wide range of sports but little is known about how stiffness and asymmetries affect CODS. Eighteen healthy males performed unilateral drop jumps to determine vertical, ankle, knee and hip stiffness, and a CODS test to evaluate left and right leg cutting performance during which ground reaction force data were sampled. A step-wise regression analysis was performed to ascertain the determinants of CODS time. A two-variable regression model explained 63% (R-2 = 0.63; P = 0.001) of CODS performance. The model included the mean vertical stiffness and jump height asymmetry determined during the drop jump. Faster athletes (n = 9) exhibited greater vertical stiffness (F = 12.40; P = 0.001) and less asymmetry in drop jump height (F = 6.02; P = 0.026) than slower athletes (n = 9); effect sizes were both "large" in magnitude. Results suggest that overall vertical stiffness and drop jump height asymmetry are the strongest predictors of CODS in a healthy, non-athletic population.
    • Does a loaded warm-up influence jump asymmetry and badminton-specific change of direction performance?

      Yeung, Wing-Chun V.; Bishop, Chris; Turner, Anthony; Maloney, Sean J.; ; Middlesex University (Human Kinetics Publishers Inc., 2021-01-31)
      Purpose: Previously, it has been shown that loaded warm-up (LWU) can improve change-of-direction speed (CODS) in professional badminton players. However, the effect of asymmetry on CODS in badminton players and the influence of LWU on asymmetry has not been examined. Methods: A total of 21 amateur badminton players (age 29.5 [8.4] y, playing experience 8.4 [4.2] y) completed 2 trials. In the first, they performed a control warm-up. In the second, they performed the same warm-up but with 3 exercises loaded with a weight vest (LWU). Following both warm-ups, players completed single-leg countermovement jump and badminton-specific CODS tests. Results: No significant differences between control warm-up and LWU were observed for CODS, single-leg countermovement jump, or single-leg countermovement jump asymmetry. However, small effect sizes suggested faster CODS (mean difference: −5%; d = −0.32) and lower asymmetries (mean difference: −3%; d = −0.39) following LWU. Five players (24%) experienced CODS improvements greater than the minimum detectable change while 2 (10%) responded negatively. Asymmetry was not correlated with CODS following control warm-up (ρ = .079; P = .733) but was negatively associated with CODS after LWU (ρ = −.491; P = .035). Conclusion: LWU may prove a strategy to trial on an individual basis, but generic recommendations should not be applied.
    • Does parental support moderate the effect of children's motivation and self-efficacy on physical activity and sedentary behaviour?

      Gillison, F.B.; Standage, M.; Cumming, S.P.; Zakrzewski-Fruer, Julia K.; Rouse, P.C.; Katzmarzyk, P.T.; University of Bath; Pennington Biomedical Research Centre (Elsevier, 2017-07-13)
      Objectives: 1) To test whether parental support moderates the direct effects of children's motivation and self-efficacy on objectively measured moderate-vigorous physical activity (MVPA) and sedentary time. 2) To explore differences in the relationships between boys and girls. Design: Cross-sectional observational study. Method: Data were collected from 430 9-11 year old UK children and their parents; parents selfreported on the support they provided to their children to be active (through providing transport, encouragement, watching, or taking part with their child), and children self-reported their motivation and self-efficacy towards exercise. MVPA and sedentary time were measured using accelerometers. Results: Both parent- and child-level factors were largely positively associated with children's MVPA and negatively related to sedentary time. There was no evidence of a moderation effect of parental support on MVPA or sedentary time in boys. Parental provision of transport moderated the effect of girls' motivation on week-day MVPA; more motivated girls were less active when transport was provided. Transport and exercising with one's child moderated the effect of motivation and self-efficacy on girls' sedentary time at weekends; more motivated girls, and those with higher self-efficacy were less sedentary when parents provided more frequent transportation or took part in physical activity with them. Conclusions: The results largely supported a model of the independent effects of parent and child determinants for moderate-to-vigorous physical activity, but there was evidence that some types of parent support can moderate sedentary time in girls. Further research is needed to explore the causal pathways between the observed cross-sectional results.
    • The dose-response to sodium bicarbonate ingestion highlights the need for individuality in supplementation

      Jones, Rebecca Louise; Stellingwerff, Trent; Artioli, Guilherme Giannini; Saunders, Bryan; Cooper, Simon; Sale, Craig; Nottingham Trent University; Canadian Sport Institute; University of São Paulo (Human Kinetics Journal, 2016-10-01)
      To defend against hydrogen cation accumulation and muscle fatigue during exercise, sodium bicarbonate (NaHCO3) ingestion is commonplace. The individualized dose-response relationship between NaHCO3 ingestion and blood biochemistry is unclear. The present study investigated the bicarbonate, pH, base excess and sodium responses to NaHCO3 ingestion. Sixteen healthy males (23 ± 2 years; 78.6 ± 15.1 kg) attended three randomized order-balanced, nonblinded sessions, ingesting a single dose of either 0.1, 0.2 or 0.3 g·kg-1BM of NaHCO3 (Intralabs, UK). Fingertip capillary blood was obtained at baseline and every 10 min for 1 hr, then every 15 min for a further 2 hr. There was a significant main effect of both time and condition for all assessed blood analytes (p ≤ .001). Blood analyte responses were significantly lower following 0.1 g·kg-1BM compared with 0.2 g·kg-1BM; bicarbonate concentrations and base excess were highest following ingestion of 0.3 g·kg-1BM (p ≤ .01). Bicarbonate concentrations and pH significantly increased from baseline following all doses; the higher the dose the greater the increase. Large interindividual variability was shown in the magnitude of the increase in bicarbonate concentrations following each dose (+2.0-5; +5.1-8.1; and +6.0-12.3 mmol·L-1 for 0.1, 0.2 and 0.3 g·kg-1BM) and in the range of time to peak concentrations (30-150; 40-165; and 75-180 min for 0.1, 0.2 and 0.3 g·kg-1BM). The variability in bicarbonate responses was not affected by normalization to body mass. These results challenge current practices relating to NaHCO3 supplementation and clearly show the need for athletes to individualize their ingestion protocol and trial varying dosages before competition.
    • Downhill running and exercise in hot environments increase leukocyte Hsp72 (HSPA1A) and Hsp90 (HSPC1) gene transcripts

      Tuttle, James A.; Castle, Paul C.; Metcalfe, Alan J.; Midgley, Adrian W.; Taylor, Lee; Lewis, Mark P.; University of Bedfordshire; Edgehill University; Loughborough University (American Physiological Society, 2015-04-15)
      Stressors within humans and other species activate Hsp72 and Hsp90 mRNA transcription, although it is unclear which environmental temperature or treadmill gradient induces the largest increase. To determine the optimal stressor for priming the Hsp system, physically active but not heat-acclimated participants (19.8 1.9 and 20.9 3.6 yr) exercised at lactate threshold in either temperate (20°C, 50% relative humidity; RH) or hot (30°C, 50% RH) environmental conditions. Within each condition, participants completed a flat running (temperate flat or hot flat) and a downhill running (temperate downhill or hot downhill) experimental trial in a randomized counterbalanced order separated by at least 7 days. Venous blood samples were taken immediately before (basal), immediately after exercise, and 3 and 24 h postexercise. RNA was extracted from leukocytes and RT-quantitative PCR conducted to determine Hsp72 and Hsp90 mRNA relative expression. Leukocyte Hsp72 mRNA was increased immediately after exercise following downhill running (1.9 0.9-fold) compared with flat running (1.3 0.4-fold; P 0.001) and in hot (1.9 0.6-fold) compared with temperate conditions (1.1 0.5-fold; P 0.003). Leukocyte Hsp90 mRNA increased immediately after exercise following downhill running (1.4 0.8-fold) compared with flat running (0.9 0.6-fold; P 0.002) and in hot (1.6 1.0-fold) compared with temperate conditions (0.9 0.6-fold; P 0.003). Downhill running and exercise in hot conditions induced the largest stimuli for leukocyte Hsp72 and Hsp90 mRNA increases.
    • Drop jump asymmetry is associated with reduced sprint and change-of-direction speed performance in adult female soccer players

      Bishop, Chris; Turner, Anthony; Maloney, Sean J.; Lake, Jason; Loturco, Irineu; Bromley, Tom; Read, Paul; Middlesex University; University of Bedfordshire; University of Chichester; et al. (MDPI, 2019-01-21)
      Studies that examine the effects of inter-limb asymmetry on measures of physical performance are scarce, especially in adult female populations. The aim of the present study was to establish the relationship between inter-limb asymmetry and speed and change-of-direction speed (CODS) in adult female soccer players. Sixteen adult players performed a preseason test battery consisting of unilateral countermovement jump (CMJ), unilateral drop jump (DJ), 10 m, 30 m, and 505 CODS tests. Inter-limb asymmetry was calculated using a standard percentage difference equation for jump and CODS tests, and Pearson's r correlations were used to establish a relationship between asymmetry and physical performance as well as asymmetry scores themselves across tests. Jump-height asymmetry from the CMJ (8.65%) and DJ (9.16%) tests were significantly greater (p < 0.05) than asymmetry during the 505 test (2.39%). CMJ-height asymmetry showed no association with speed or CODS. However, DJ asymmetries were significantly associated with slower 10 m (r = 0.52; p < 0.05), 30 m (r = 0.58; p < 0.05), and 505 (r = 0.52⁻0.66; p < 0.05) performance. No significant relationships were present between asymmetry scores across tests. These findings suggest that the DJ is a useful test for detecting existent between-limb asymmetry that might in turn be detrimental to speed and CODS performance. Furthermore, the lack of relationships present between different asymmetry scores indicates the individual nature of asymmetry and precludes the use of a single test for the assessment of inter-limb differences.
    • Editorial: Sedentary behaviour in human health and disease

      Bailey, Daniel Paul; University of Bedfordshire (Frontiers Media, 2017-11-07)
    • Effect of breakfast omission and consumption on energy intake and physical activity in adolescent girls: a randomised controlled trial

      Zakrzewski-Fruer, Julia K.; Plekhanova, Tatiana; Mandila, D.; Lekatis, Y.; Tolfrey, Keith; University of Bedfordshire; Loughborough University (Cambridge University Press, 2017-09-13)
      It is not known if breakfast consumption is an effective intervention for altering daily energy balance in adolescents when compared with breakfast omission. This study examined the acute effect of breakfast consumption and omission on free-living energy intake (EI) and physical activity (PA) in adolescent girls. Using an acute randomised crossover design, forty girls (age 13.3 ± 0.8 y, body mass index 21.5 ± 5.0 kg∙m-2) completed two, 3-day conditions in a randomised, counter-balanced order: no breakfast (NB) and standardised (~1962 kJ) breakfast (SB). Dietary intakes were assessed using food diaries combined with digital photographic records and PA was measured via accelerometry throughout each condition. Statistical analyses were completed using repeated measures analysis of variance. Post-breakfast EI was 483 ± 1309 kJ/d higher in NB vs. SB (P=0.025), but total daily EI was 1479 ± 1311 kJ/d higher in SB vs. NB (P<0.0005). Daily carbohydrate, fibre and protein intakes were higher in SB vs. NB (P<0.0005), whereas daily fat intake was not different (P=0.405). Effect sizes met the minimum important difference of ≥0.20 for all significant effects. Breakfast manipulation did not affect post-breakfast macronutrient intakes (P≥0.451) or time spent sedentary or in PA (P≥0.657). In this sample of adolescent girls, breakfast omission increased post-breakfast free-living EI, but total daily EI was greater when a standardised breakfast was consumed. We found no evidence that breakfast consumption induces compensatory changes in PA. Further experimental research is required to determine the effects of extended periods of breakfast manipulation in young people.
    • The effect of different environmental conditions on the decision-making performance of soccer goal line officials

      Watkins, Samuel L.; Castle, Paul C.; Mauger, Alexis R.; Sculthorpe, Nicholas; Fitch, Natalie; Aldous, Jeffrey William Frederick; Brewer, John; Midgley, Adrian W.; Taylor, Lee (Taylor and Francis Inc., 2014-10-08)
      Goal line officials (GLO) are exposed to extreme environmental conditions when employed to officiate in professional European soccer cup competitions. The present study aimed to investigate the effect of such environments on GLO decision-making ability. Thirteen male participants were exposed to three conditions: cold (-5°C, 50% relative humidity (RH)); temperate (18°C, 50% RH); and hot (30°C, 50% RH) for 90 min per condition, with a 15 min half-time break after 45 min. Decision-making ability was assessed throughout the 90 min exposure. Core and skin temperatures were recorded throughout. Decision making was improved during exposure to the temperate condition when compared with the cold (mean difference = 12.5%; 95% CI = 1.1%, 23.9%; P = 0.031). Regression analysis indicated that as skin temperature increases so does decision-making ability. Exposure to cold conditions diminished the decision-making ability of GLO.
    • The effect of dimple error on the horizontal launch angle and side spin of the golf ball during putting

      Richardson, Ashley K; Mitchell, Andrew C.S.; Hughes, Gerwyn T.G.; University of Abertay Dundee; University of Bedfordshire; University of Hertfordshire (TAYLOR & FRANCIS LTD, 2016-03-16)
      This study aimed to examine the effect of the impact point on the golf ball on the horizontal launch angle and side spin during putting with a mechanical putting arm and human participants. Putts of 3.2m were completed with a mechanical putting arm (four putter-ball combinations, total of 160 trials) and human participants (two putter-ball combinations, total of 337 trials). The centre of the dimple pattern (centroid) was located and the following variables were measured: distance and angle of the impact point from the centroid and surface area of the impact zone. Multiple regression analysis was conducted to identify whether impact variables had significant associations with ball roll variables, horizontal launch angle and side spin. Significant associations were identified between impact variables and horizontal launch angle with the mechanical putting arm but this was not replicated with human participants. The variability caused by dimple error was minimal with the mechanical putting arm and not evident with human participants. Differences between the mechanical putting arm and human participants may be due to the way impulse is imparted on the ball. Therefore it is concluded that variability of impact point on the golf ball has a minimal effect on putting performance.
    • The effect of expertise on coordination variability during a discrete multi-articular action

      Jones, Rebecca Louise; Robins, M. (2017-09-20)
      Introduction When investigating the relationship between task expertise and movement variability, contrasting findings have been reported in scientific literature (e.g. Darling and Cooke, 1987; Wilson, et al., 2008; Robins, et al., 2008). These equivocal reports could be due, to task constraints influencing variability magnitudes. Whilst some research has used static accuracy-based tasks (Darling and Cooke, 1987), more complex, dynamic multi-articular movements tasks have also been used (Wilson, et al., 2008; Robins, et al., 2008). Currently there is a lack of research examining task expertise-movement variability during such dynamic movement tasks, and ultimately how movement variability can be used functionally to satisfy the specific constraints on action. Therefore, the purpose of this study was to examine the interaction of expertise and coordination variability during a dynamic basketball shooting task. Methods Male university basketball players (n=8) with varying basketball experience (scoring between 35-80% of pre-test shots) performed 20 shots from a distance of 4.25 metres after a dribbling movement of 6.5 metres. Kinematic data was collected from a seven-camera motion capture system sampling at 200Hz. 14mm reflective markers attached to upper limb anatomical landmarks allowed calculation of shoulder, elbow and wrist angular displacements. Coordination variability for the wrist-elbow, elbow-shoulder, and wrist-shoulder joint couplings were produced using the normalised root mean squared difference (NoRMS) approach. Providing a metric by which the degree of consistency may be assessed, as such, one measure of stability of the underlying coordination. Quadratic regression analysis was used to identify the potential relationship between joint coupling coordination variability and shooting score. Results The quadratic regression values for the wrist-elbow joint coupling was 0.1609 (p=0.48), elbow-shoulder, 0.1109 (p=0.66), and wrist-shoulder, 0.6467 (p=0.02) with respect to shooting performance score. Discussion Similar to previous research, task performance and coordination variability demonstrated an U-shaped relationship (Wilson, et al., 2008). Intermediate skilled participants displayed the lowest coordination variability; whilst higher skilled participants demonstrated higher functional variability owing to adapting to perturbations (Hamill, 1999). Least skilled participants revealed variability that is less functional and evident of less stable movement patterns. Additional research is needed, to further understand the task expertise-movement variability relationship for different task constraints
    • The effect of movement variability on putting proficiency during the golf putting stroke

      Richardson, Ashley K; Mitchell, Andrew C.S.; Hughes, Gerwyn T.G.; Abertay University; University of Bedfordshire; University of San Francisco (SAGE Publications Inc., 2018-04-04)
      Movement variability has been considered important to execute an effective golf swing yet is comparatively unexplored regarding the golf putt. Movement variability could potentially be important considering the small margins of error between a successful and a missed putt. The aim of this study was to assess whether variability of body segment rotations influence putting performance (ball kinematic measures). Eight golfers (handicap range 0–10) performed a 3.2 m level putt wearing retro-reflective markers which were tracked using a three-dimensional motion analysis system sampling at 120 Hz. Ball roll kinematics were recorded using Quintic Ball Roll launch monitor. Movement (segment) variability was calculated based on a scalene ellipsoid volume concept and correlated with the coefficient of variation of ball kinematics. Statistical analysis showed no significant relationships between segment variability and putting proficiency. One significant relationship was identified between left forearm variability and horizontal launch angle, but this did not result in deficits in putting success. Results show that performance variability in the backswing and downswing is not related to putting proficiency or the majority of ball roll measures. Differing strategies may exist where certain golfers may have more fluid movement patterns thereby effectively utilising variability of movement. Therefore, golf instructors should consider movement variability when coaching the golf putt.
    • The effect of pre and per-cooling on intermittent-sprint exercise in the heat: a systematic review and meta-analysis

      Scott, Jake; Gordon, Ralph; Tyler, Chris; Aldous, Jeffrey William Frederick; University of Bedfordshire (University of Bedfordshire, 2021-05)
      Systematic review and meta-analysis protocol for a PhD study.
    • The effect of repetitive ankle perturbations on muscle reaction time and muscle activity

      Thain, Peter K.; Hughes, Gerwyn T.G.; Mitchell, Andrew C.S.; Birmingham City University; University of San Francisco; University of Bedfordshire; University of Hertfordshire (Elsevier Ltd, 2016-07-15)
      The use of a tilt platform to simulate a lateral ankle sprain and record muscle reaction time is a well-established procedure. However, a potential caveat is that repetitive ankle perturbation may cause a natural attenuation of the reflex latency and amplitude. This is an important area to investigate as many researchers examine the effect of an intervention on muscle reaction time. Muscle reaction time, peak and average amplitude of the peroneus longus and tibialis anterior in response to a simulated lateral ankle sprain (combined inversion and plantar flexion movement) were calculated in twenty-two physically active participants. The 40 perturbations were divided into 4 even groups of 10 dominant limb perturbations. Within-participants repeated measures analysis of variance (ANOVA) tests were conducted to assess the effect of habituation over time for each variable. There was a significant reduction in the peroneus longus average amplitude between the aggregated first and last 10 consecutive ankle perturbations (F = 3.90, P = 0.03, ɳ  = 0.16). Authors should implement no more than a maximum of 30 consecutive ankle perturbations (inclusive of practice perturbations) in future protocols simulating a lateral ankle sprain in an effort to avoid significant attenuation of muscle activity.
    • Effect of tyrosine ingestion on cognitive and physical performance utilising an intermittent soccer performance test (iSPT) in a warm environment

      Coull, Nicole; Watkins, Samuel L.; Aldous, Jeffrey William Frederick; Warren, Lee K.; Chrismas, Bryna C.; Dascombe, Ben; Mauger, Alexis R.; Abt, Grant; Taylor, Lee (Springer, 2014-10-19)
      Abstract Purpose The aim of this study was to investigate the effect of tyrosine (TYR) ingestion on cognitive and physical performance during soccer-specific exercise in a warm environment. Methods Eight male soccer players completed an individualised 90 min soccer-simulation intermittent soccer performance test (iSPT), on a non-motorised treadmill, on two occasions, within an environmental chamber (25 °C, 40 % RH). Participants ingested tyrosine (TYR; 250 mL sugar free drink plus 150 mg kg body mass−1 TYR) at both 5 h and 1 h pre-exercise or a placebo control (PLA; 250 mL sugar free drink only) in a double-blind, randomised, crossover design. Cognitive performance (vigilance and dual-task) and perceived readiness to invest physical effort (RTIPE) and mental effort (RTIME) were assessed: pre-exercise, half-time, end of half-time and immediately post-exercise. Physical performance was assessed using the total distance covered in both halves of iSPT. Results Positive vigilance responses (HIT) were significantly higher (12.6 ± 1.7 vs 11.5 ± 2.4, p = 0.015) with negative responses (MISS) significantly lower (2.4 ± 1.8 vs 3.5 ± 2.4, p = 0.013) in TYR compared to PLA. RTIME scores were significantly higher in the TYR trial when compared to PLA (6.7 ± 1.2 vs 5.9 ± 1.2, p = 0.039). TYR had no significant (p > 0.05) influence on any other cognitive or physical performance measure. Conclusion The results show that TYR ingestion is associated with improved vigilance and RTIME when exposed to individualised soccer-specific exercise (iSPT) in a warm environment. This suggests that increasing the availability of TYR may improve cognitive function during exposure to exercise-heat stress.