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1.
F1000Res ; 10: 411, 2021.
Article in English | MEDLINE | ID: mdl-38633212

ABSTRACT

Twenty20 cricket and batting in particular have remained vastly understudied to date. To elucidate the effects of batting on the batter, tools which replicate match play in controlled environments are essential. This study describes the development of two Twenty20 batting simulations, for a high and low strike rate innings, generated from retrospective analysis of international and domestic competition. Per delivery analysis of probabilities of run-type and on/off-strike denomination produce ball-by-ball simulations most congruent with retrospective competitive innings. Furthermore, both simulations are matched for duration and dictated through audio files. The `high' strike rate innings requires a batter to score 88 runs from 51 deliveries, whereby 60 runs are from boundaries. Similarly, the `low' strike rate innings requires a batter to score 61 runs from 51 deliveries, where 27 runs are scored from boundaries. Because batting simulations dictate run scoring outcomes, a method of quantifying a batter's performance from bat-ball contact scores is described. Ten elite batters achieved a mean performance score of 72 (SD = 26) and 88 (21) for the low and high strike rate simulations respectively. This study provides sport practitioners with a training technique to improve specific skill acquisition and enables research in understudied Twenty20 batting.


Subject(s)
Athletic Performance , Retrospective Studies
2.
Am J Clin Nutr ; 110(2): 349-357, 2019 08 01.
Article in English | MEDLINE | ID: mdl-31098615

ABSTRACT

BACKGROUND: The high-fat ketogenic diet (KD) has become an increasingly popular diet not only in overweight/obese populations, or those with clinical conditions, but also in healthy non-overweight populations. OBJECTIVE: Because there are concerns about the association between high-fat diets and cognitive decline, this study aimed to determine the effects of a KD compared with an isocaloric high-carbohydrate, low-fat (HCLF) diet on cognitive function, sleep, and mood in healthy, normal-weight individuals. METHODS: Eleven healthy, normal-weight participants (mean age: 30 ± 9 y) completed this randomized, controlled, crossover study. Participants followed 2 isocaloric diets-an HCLF diet (55% carbohydrate, 20% fat, and 25% protein) and a KD (15% carbohydrate, 60% fat, and 25% protein)-in a randomized order for a minimum of 3 wk, with a 1-wk washout period between diets. Measures of ß-hydroxybutyrate confirmed that all participants were in a state of nutritional ketosis during post-KD assessments (baseline: 0.2 ± 0.2 mmol/L; KD: 1.0 ± 0.5 mmol/L; washout: 0.2 ± 0.1 mmol/L; and HCLF: 0.3 ± 0.2 mmol/L). Cognitive function was assessed using a validated, psychological computer-based test battery before and after each diet. Subjective measures of mood and sleep were also monitored throughout the study using validated scales. RESULTS: Three weeks of sustained nutritional ketosis, compared with the HCLF diet, had no effect on speed and accuracy responses in tasks designed to measure vigilance (speed: P = 0.39, Cohen's d = 0.26; accuracy: P = 0.99, Cohen's d = 0.04), visual learning and memory (speed: P = 0.99, Cohen's d = 0.04; accuracy: P = 0.99, Cohen's d = 0.03), working memory (speed: P = 0.62, Cohen's d = 0.26; accuracy: P = 0.98, Cohen's d = 0.07), and executive function (speed: P = 0.60, Cohen's d = 0.31; accuracy: P = 0.90, Cohen's d = 0.19). Likewise, mood, sleep quality, and morning vigilance did not differ (P > 0.05) between the dietary interventions. CONCLUSION: The results of our randomized, crossover, controlled study suggest that 3 wk of sustained nutritional ketosis had no effect on cognitive performance, mood, or subjective sleep quality in a sample of healthy individuals. This trial was registered in the Pan African Clinical Trial Registry as PACTR201707002406306.


Subject(s)
Affect/drug effects , Cognition/drug effects , Dietary Carbohydrates/administration & dosage , Dietary Fats/administration & dosage , Ketosis/chemically induced , Sleep/drug effects , Adult , Body Composition/drug effects , Cross-Over Studies , Diet, Fat-Restricted , Diet, Ketogenic , Female , Humans , Male , Young Adult
3.
J Strength Cond Res ; 33(11): 3056-3064, 2019 Nov.
Article in English | MEDLINE | ID: mdl-29746385

ABSTRACT

Christie CJ, Sheppard B, Goble D, Pote L, and Noakes TD. Strength and sprint time changes in response to repeated shuttles between the wickets during batting in cricket. J Strength Cond Res 33(11): 3056-3064, 2019-No studies have investigated the impact of repeated sprints between the wickets on lower-limb strength and sprint performance. Therefore, the purpose of this study was to assess changes in knee extensor (EXT) and flexor (FLEX) strength after repeated sprints between the wickets and to relate these to changes in sprint times. Twenty batters completed 2 conditions: one was high-volume running (HVR-twelve sprints per over) and the other, moderate-volume running (MVR-6 sprints per over) between the wickets (42 deliveries in both). Peak isokinetic torque was measured before and after each condition and sprint times were recorded. Eccentric and concentric peak torque decreased significantly (p < 0.05) at 1.05 rad·s for knee EXT in both conditions. There was an 18% (HVR) and 10% (MVR) decline in concentric and eccentric knee EXT peak torque. Peak FLEX torques were significantly (p < 0.05) reduced after HVR (16.7%) but not after the MVR condition (8%). There were similar declines in eccentric FLEX peak torque. Sprint times increased significantly (p < 0.05) during the HVR condition but not in the MVR condition; sprint times in the HVR condition were compromised as early as the third over. We conclude that a high volume of runs significantly reduces muscle function in the lower limbs, partly explaining the impairment in sprint performance. However, because batters slowed as early as the third over in the HVR condition, there may be some form of strategy used in anticipation of a higher overall workload. More middle wicket practices, focusing on repeat shuttle sprints while batting, should be included in the coaching program.


Subject(s)
Cricket Sport/physiology , Muscle, Skeletal/physiology , Running/physiology , Adolescent , Adult , Analysis of Variance , Cross-Over Studies , Humans , Knee/physiology , Male , Muscle Strength , Torque , Young Adult
4.
J Occup Environ Med ; 60(8): 760-767, 2018 08.
Article in English | MEDLINE | ID: mdl-29608541

ABSTRACT

OBJECTIVE: The aim of this study was to determine whether mobile phone text messages could modify objectively measured sedentary behavior and cardiometabolic health in office workers. METHODS: Nine males and 12 females [mean (SD): 27.5 (5.7) years, 23.8 (2.8) kg/m] were assigned to a control (CON) or intervention (PROMPT) group. PROMPT received an activity-promoting text message during office hours. Participants wore an actiGraph and activPAL accelerometer for 7 days during and after the intervention. Blood pressure, lipid, and metabolic profiles were measured before and after the intervention. RESULTS: PROMPT sat less [mean (95% confidence interval, 95% CI): 4.9 (4.4 to 5.4) hours/day] than CON [6.0 (5.5 to 6.4) hours/day; P = 0.04] during the message-receiving period. There was no difference between groups after the intervention and for the other activity variables. There were no changes in cardiometabolic health markers following the intervention. CONCLUSION: Sitting time was lower during the message-receiving period, but the difference between groups was no longer apparent after the intervention.


Subject(s)
Health Promotion/methods , Lipoprotein Lipase/blood , Occupational Health , Sedentary Behavior , Text Messaging , Actigraphy , Adult , Blood Glucose/metabolism , Blood Pressure , Cardiorespiratory Fitness , Exercise Test , Female , Humans , Insulin/blood , Lipoproteins/blood , Male , Pilot Projects , Sitting Position , Standing Position , Time Factors , Workplace , Young Adult
5.
J Sports Sci ; 35(12): 1148-1154, 2017 Jun.
Article in English | MEDLINE | ID: mdl-27467711

ABSTRACT

The purpose of this study was to assess how cognitive and physical performance are affected during a prolonged, fatigue-inducing cricket-batting simulation. Fifteen amateur batters from three Eastern Cape schools in South Africa were recruited (mean ± SD: age 17 ± 0.92 years; stature 1.75 ± 0.07 m; body mass 78.3 ± 13.2 kg). Participants completed a 6-stage, 30-over batting simulation (BATEX©). During the protocol, there were five periods of cognitive assessment (CogState brief test battery, Melbourne, Australia). The primary outcome measures from each cognitive task were speed and accuracy/error rates. Physiological (heart rate) and physical (sprint times) responses were also recorded. Sprint times deteriorated (d = 0.84; P < 0.01) while physiological responses increased (d = 0.91; P < 0.01) as batting duration increased, with longest times and highest responses occurring in the final stage. Prolonged batting had a large effect on executive task performance (d = 0.85; P = 0.03), and moderate effects on visual attention and vigilance (d = 0.56; P = 0.21) and attention and working memory (d = 0.61; P = 0.11), reducing task performance after 30 overs. Therefore, prolonged batting with repeated shuttle running fatigues amateur batters and adversely affects higher-order cognitive function. This will affect decision-making, response selection, response execution and other batting-related executive processes. We recommend that training should incorporate greater proportions of centre-wicket batting with repeated, high-intensity shuttle running. This will improve batting-related skills and information processing when fatigued, making practice more representative of competition.


Subject(s)
Athletic Performance/physiology , Athletic Performance/psychology , Cognition/physiology , Muscle Fatigue/physiology , Sports/physiology , Sports/psychology , Adolescent , Attention/physiology , Decision Making/physiology , Executive Function/physiology , Heart Rate/physiology , Humans , Male , Memory/physiology , Running/physiology , Task Performance and Analysis
6.
J Nat Prod ; 72(6): 1075-80, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19419186

ABSTRACT

Chemical investigation of the Australian plant Haemodorum simplex resulted in the isolation of three new phenylphenalenones, haemodorone (10), haemodorol (11), and haemodorose (12), together with the previously reported compounds 5, dilatrin (6), and xiphidone (8). The first complete 2D NMR characterization for all of the compounds isolated, including several chemical shift reassignments for dilatrin (6), is reported. In addition this is one of the few reports to discuss the isolation of new phenylphenalenones from an Australian medicinal plant. The crude extract of both the bulbaceous and aerial components of the plant exhibited varying degrees of antibacterial, antifungal, and antiviral activity, and only the bulbs displayed potent cytotoxic activity.


Subject(s)
Antineoplastic Agents, Phytogenic/isolation & purification , Magnoliopsida/chemistry , Phenalenes/isolation & purification , Plants, Medicinal/chemistry , Animals , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/pharmacology , Australia , Drug Screening Assays, Antitumor , Inhibitory Concentration 50 , Leukemia P388 , Mice , Microbial Sensitivity Tests , Molecular Structure , Phenalenes/chemistry , Phenalenes/pharmacology , Poliovirus/drug effects , Simplexvirus/drug effects
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