Search PubMed⌕ Search

Biomedical subjects

T Reilly

Publications and source records attributed to T Reilly.

At least 19 recordsLinked to original sources
PubMed2007

Biological maturity and injury in elite youth football.

The purpose of the present study was to investigate injury according to biological maturity in elite under-14 youth football players based at the National Football Institute, France. Over 10 seasons, injury incidence, severity and distribution were compared in 233 players classed according to individual biological maturity determined by skeletal age into three cohorts as early, normal and late maturers.A non-significant higher injury incidence was found in early and normal maturers compared with late maturers. In contrast, the latter group sustained a significantly higher incidence of major injuries compared with early maturers (0.3 vs 0.6 vs 0.9, P=0.039). A significantly higher incidence of osteochrondoses was reported in normal and late maturers (0.3 vs 0.7 vs 0.9, P=0.014), whereas tendinopathy incidence was greater in early and normal maturers (0.06 vs 0.08 vs 0.02, P=0.033). Early maturers incurred the highest incidence of groin strains and re-injuries (P<0.05). There was no significant difference between groups in the seasonal disposition of injury.Biological maturity status did not significantly affect overall injury incidence in elite French youth football players, although there were differences between maturity groups when patterns of injury location, type, severity and re-injury were analyzed.

Adolescent↗
PubMed2006

Reliability of repeated sprint exercise in non-motorised treadmill ergometry.

Although repeated sprint tests are relatively common, there have been few investigations of repeated sprint exercise using non-motorised treadmill ergometry. The purpose of this study was to determine the reliability of a repeated sprint procedure using this apparatus. Ten healthy, active males, performed three repeated sprint tests (six repetitions of 6 s sprints with 30 s recovery) on three separate occasions. Performance as determined by maximal speed, average force production, and fatigue were compared across the three trials. Maximal speed and average force were not significantly different between visits (p < 0.05) and a variety of reliability measures suggested good agreement (e.g., coefficient of variations no more than 5 %). The fatigue indices for maximal speed and for average force were generally less reliable (coefficients of variation around 30 % in both cases). In conclusion, measures of performance (maximal speed and average force) can provide reliable results in a repeated sprint protocol but the reliability of fatigue measures appears to be low.

Adult↗
PubMed2006

Salivary IgA response to intermittent and continuous exercise.

Current evidence would support a view that intense exercise increases whereas moderate exercise reduces the susceptibility to illness, predominately upper respiratory tract infections. Concentrations of IgA and cortisol in saliva may be used to reflect changes in immune function. The aim of this study was to determine if the type of exercise (soccer-specific intermittent or continuous exercise at the same average work-rate and duration) affects salivary IgA (s-IgA) and cortisol responses. In a randomized, counterbalanced design, eight healthy males completed two trials one week apart at the same time of day on a motorized treadmill. One session entailed soccer-specific intermittent exercise, the other involved continuous exercise at the same overall work-rate. Diet and activity were standardized for 48 hours prior to and following each trial. Unstimulated saliva samples were collected via passive expectoration during the week prior to commencement of exercise, before, at half-time, immediately post-exercise, and 6 hours, 24 hours, and 48 hours post-exercise. No significant difference was observed in heart rate between the two exercise conditions (Intermittent: 142 +/- 14; Continuous: 141 +/- 16 beats x min (-1)). Average rating of perceived exertion was higher (p < 0.05) in intermittent exercise (11.9 +/- 0.8) than during continuous exercise (10.8 +/- 1.2). The pattern of change in salivary responses, including solute secretion rate, IgA concentration, IgA secretion rate, IgA to osmolality ratio, cortisol, and cortisol secretion rate did not differ between the two trials (p > 0.05). Concentrations of s-IgA for the intermittent and continuous protocols were 131.6 +/- 61.2 vs. 146.4 +/- 107.6 before, 148.4 +/- 82.5 vs. 229.2 +/- 159.6 after, and 125 +/- 78.7 vs. 131.1 +/- 80.7 48 h post-exercise, respectively. Saliva flow rate decreased and osmolality increased significantly across all time points (p < 0.05). In conclusion, soccer-specific intermittent exercise did not suppress the salivary IgA response or alter cortisol secretion compared to continuous exercise performed at the same overall work-rate.

Adult↗
PubMed2006

Physiological and performance effects of generic versus specific aerobic training in soccer players.

The aim of this study was to compare the effects of specific (small-sided games) vs. generic (running) aerobic interval training on physical fitness and objective measures of match performance in soccer. Forty junior players were randomly assigned to either generic (n=20) or specific (n=20) interval training consisting of 4 bouts of 4 min at 90-95 % of maximum heart rate with 3 min active rest periods, completed twice a week. The following outcomes were measured at baseline (Pre), after 4 weeks of pre-season training (Mid), and after a further 8 weeks of training during the regular season (Post): maximum oxygen uptake, lactate threshold (Tlac), running economy at Tlac, a soccer-specific endurance test (Ekblom's circuit), and indices of physical performance during soccer matches (total distance and time spent standing, walking, and at low- and high-intensity running speed). Training load, as quantified by heart rate and rating of perceived exertion, was recorded during all training sessions and was similar between groups. There were significant improvements in aerobic fitness and match performance in both groups of soccer players, especially in response to the first 4 weeks of pre-season training. However, no significant differences between specific and generic aerobic interval training were found in any of the measured variables including soccer specific tests. The results of this study showed that both small-sided games and running are equally effective modes of aerobic interval training in junior soccer players.

Adolescent↗
PubMed2005

Occupational fitness standards for beach lifeguards. Phase 1: the physiological demands of beach lifeguarding.

BACKGROUND: Although similar standards exist internationally to select beach lifeguards (BLGs), these are generally not based on a task analysis. To reduce the likelihood of drowning, a BLG should reach a casualty within 3.5 min (210 s). AIM: To quantify the physical demands of the most critical generic tasks undertaken by BLGs. METHODS: A survey of 91 BLGs identified sea swimming while towing a casualty, board paddling with a casualty, and casualty handling as the most demanding activities. Performance during beach running (200 m), swimming in the sea (200 m), board paddling in the sea (400 m), swimming in a pool (200 m freestyle and 25 m underwater with 25 m return) and simulated casualty handling were measured. RESULTS: The median area at sea patrolled by paddling and swimming was 400 m. The mean 200-m sea swim time was 3.1 min or 188 s (SD = 46 s) and 95% of the BLGs were able to swim 200 m in 3.5 min (n = 22). The mean time to paddle 400 m was 3.8 min or 226 s (SD = 35 s) and 30% of the BLGs were able to paddle 400 m in 3.5 min (n = 23). The 5th percentile paddling speed was 1.38 m/s, therefore, 95% of the BLGs tested should be able to paddle 289 m in 3.5 min. CONCLUSIONS: If only a rescue board is available, the area out to sea patrolled by a lifeguard should be reduced from 400 m to 300 m.

Adolescent↗
PubMed2005

Occupational fitness standards for beach lifeguards. Phase 2: the development of an easily administered fitness test.

BACKGROUND: No task-based fitness standard currently exists for beach lifeguards (BLGs). AIM: To formulate an easily administered fitness test for BLGs based on the physical demands identified in Phase 1 of the project (previous paper). METHODS: A range of anthropometric and land- and water-based (swimming pool and flume) fitness assessments were administered to 25 male and female volunteer subjects (13 BLGs from the UK). RESULTS: The mean (SD) VO(2max) (l/min) were 3.04 (0.61) for towing a casualty, 2.08 (0.53) for board paddling with a casualty and 2.97 (0.67) for freestyle swimming. A significant correlation (r = -0.82, P < 0.001) was identified between distance paddled in the sea in 3.5 min (established in Phase 1) and pool 400-m front crawl swim time and between towing VO(2max) and deltoid circumference/log(10) 400-m front crawl swim time (r = -0.83, P < 0.001). CONCLUSIONS: The regression identified allows the conclusion that if a BLG can swim 400-m front crawl in a pool in <7.5 min, he/she should be able to paddle 310 m in the sea in <3.5 min. Final recommendations for a fitness test for potential BLGs are presented.

Adolescent↗
PubMed2005

Can cycling performance in an early morning, laboratory-based cycle time-trial be improved by morning exercise the day before?

The normal circadian rhythm in exercise performance may be altered by the habitual timing of training. We have investigated if morning time trial performance is affected by the time at which moderate exercise is performed on the previous day. Eight male cyclists undertook two separate exercise sessions of sub-maximal cycle ergometry (60% V.O2peak for 30 min) at 07:00 h and 12:00 h the day before a 16.1-km time trial at 07:00 h. Heart rate, power output, ratings of perceived exertion, and rectal temperature were measured at rest and every 5 min in the pre-time trial exercises, and every 1.61 km during the time trial. Blood samples were taken at rest and immediately after the time trial for the measurement of lactate concentration. The time trial performed the day after the 07:00 h sub-maximal exercise was completed in 1672+/-135 s, compared to 1706+/-159 s for the time trial performed the day after the noon pre-time trial exercise (p=0.027). The time trial after exercise the previous morning was associated with higher work-rates (p=0.031), a higher net lactate accumulation after the time trial (p=0.018), and a trend for higher heart rates (p=0.093) compared to the time trial after exercise the previous noon. These findings suggest that cycling performance in an early morning time trial is improved if an athlete participates in early-morning rather than noontime moderate exercise the day before. This finding cannot be attributed to the physiological responses to the exercise on the pre-time trial day or to environmental factors. It is suggested that it might partly reflect an advantage gained by performing exercise in the day(s) immediately beforehand at the same time as the competition.

Adult↗
PubMed2005

Circadian rhythms in sports performance--an update.

We discuss current knowledge on the description, impact, and underlying causes of circadian rhythmicity in sports performance. We argue that there is a wealth of information from both applied and experimental work, which, when considered together, suggests that sports performance is affected by time of day in normal entrained conditions and that the variation has at least some input from endogenous mechanisms. Nevertheless, precise information on the relative importance of endogenous and exogenous factors is lacking. No single study can answer both the applied and basic research questions that are relevant to this topic, but an appropriate mixture of real-world research on rhythm disturbances and tightly controlled experiments involving forced desynchronization protocols is needed. Important issues, which should be considered by any chronobiologist interested in sports and exercise, include how representative the study sample and the selected performance tests are, test-retest reliability, as well as overall design of the experiment.

Behavior↗
PubMed2005

Strategies for hydration and energy provision during soccer-specific exercise.

The aim of the present study was to investigate the effect of manipulating the provision of sports drink during soccer-specific exercise on metabolism and performance. Soccer players (N = 12) performed a soccer-specific protocol on three occasions. On two, 7 mL/kg carbohydrate-electrolyte (CHOv) or placebo (PLA) solutions were ingested at 0 and 45 min. On a third, the same total volume of carbohydrate-electrolyte was consumed (CHOf) in smaller volumes at 0, 15, 30, 45, 60, and 75 min. Plasma glucose, glycerol, non-esterified free fatty acids (NEFA), cortisol, and CHO oxidation were not significantly different between CHOv and CHOf (P > 0.05). Sprint power was not significantly affected (P > 0.05) by the experimental trials. This study demonstrates when the total volume of carbohydrate consumed is equal, manipulating the timing and volume of ingestion elicits similar metabolic responses without affecting exercise performance.

Adult↗
PubMed2005

Does oral contraceptive use affect maximum force production in women?

OBJECTIVE: To examine the effects of oral contraceptive use on maximum force production in young women. METHODS: In the study, 21 female subjects (14 pill users and seven eumenorrheic controls) took part. All pill using subjects had been taking a combined, monophasic oral contraceptive pill for at least 6 months. Maximum dynamic and isometric leg strength, maximum isometric strength of the first dorsal interosseus (FDI) muscle, and plasma concentrations of oestradiol and progesterone were measured on days 7 and 14 of pill consumption and day 5 of pill withdrawal. The eumenorrheic group was tested (FDI strength and hormone concentrations) on days 2 and 21 of the menstrual cycle. RESULTS: There were no significant changes in the concentration of endogenous oestradiol or progesterone or any measure of muscle strength between pill phases (p<0.05). The pill group did not significantly differ from the eumenorrheic group (p<0.05), despite a significant increase in the concentration of progesterone and oestradiol on day 21 of the menstrual cycle compared with day 2 of the menstrual cycle and pill consumption and withdrawal (p<0.05). CONCLUSIONS: These data suggest that oral contraceptive use does not significantly affect muscle strength. Moreover, oral contraceptive users were not stronger or weaker than their eumenorrheic counterparts.

Adult↗
PubMed2005

Biological risk indicators for recurrent non-specific low back pain in adolescents.

OBJECTIVES: A matched case-control study was carried out to evaluate biological risk indicators for recurrent non-specific low back pain in adolescents. METHODS: Adolescents with recurrent non-specific low back pain (symptomatic; n = 28; mean (SD) age 14.9 (0.7) years) and matched controls (asymptomatic; n = 28; age 14.9 (0.7) years) with no history of non-specific low back pain participated. Measures of stature, mass, sitting height, sexual maturity (Tanner self assessment), lateral flexion of the spine, lumbar sagittal plane mobility (modified Schober), hip range of motion (Leighton flexometer), back and hamstring flexibility (sit and reach), and trunk muscle endurance (number of sit ups) were performed using standardised procedures with established reliability. Backward stepwise logistic regression analysis was performed, with the presence/absence of recurrent low back pain as the dependent variable and the biological measures as the independent variables. RESULTS: Hip range of motion, trunk muscle endurance, lumbar sagittal plane mobility, and lateral flexion of the spine were identified as significant risk indicators of recurrent low back pain (p<0.05). Follow up analysis indicated that symptomatic subjects had significantly reduced lateral flexion of the spine, lumbar sagittal plane mobility, and trunk muscle endurance (p<0.05). CONCLUSIONS: Hip range of motion, abdominal muscle endurance, lumbar flexibility, and lateral flexion of the spine were risk indicators for recurrent non-specific low back pain in a group of adolescents. These risk indicators identify the potential for exercise as a primary or secondary prevention method.

Adolescent↗
PubMed2004

Circadian rhythms in blood lactate concentration during incremental ergometer rowing.

This study examined whether circadian rhythms affect lactate threshold (Th(lac)) during rowing exercise. Eleven male, endurance-trained athletes [mean (SD) age 29.5 (6.1) years] rowed at 0200, 0600, 1000, 1400, 1800 and 2200 hours under the same experimental conditions. Capillary blood (25 microl) was obtained from the tip of the toe during the last 30 s of a continuous, multi-stage, 3-min, incremental protocol on the Concept II ergometer. To determine Th(lac), a curve-fitting procedure (the D(max) method), a visual method (Th(lac-vis)) and the fixed blood lactate concentration of 4.0 mmol l(-1) (Th(lac-4 mM)) were used. Circadian rhythms were apparent for oxygen consumption and heart rate at Th(lac) using the D(max) method (P=0.02 and P=0.04 respectively), with the acrophases at 2139 hours and 2032 hours respectively coinciding in phase with that of core body temperature. The conclusion is that tests should be completed at the same time of day at which the athlete usually trains, to ensure precision of Th(lac) determination, especially when the D(max )method is used to determine Th(lac).

Adaptation, Physiological↗
PubMed2004

The stress of travel.

International travel is an essential part of the life of elite athletes, both for competition and training. It is also becoming increasingly common among recreational sportspersons. Long-distance travel is associated with a group of transient negative effects, collectively referred to as 'travel fatigue', which result from anxiety about the journey, the change to an individual's daily routine, and dehydration due to time spent in the dry air of the aircraft cabin. Travel fatigue lasts for only a day or so, but for those who fly across several time zones, there are also the longer-lasting difficulties associated with 'jet lag'. The problems of jet lag can last for over a week if the flight crosses 10 time zones or more, and they can reduce performance and the motivation to train effectively. Knowledge of the properties of the body clock enables the cause of the difficulties to be understood (an unadjusted body clock), and forms the basis of using light in the new time zone to promote adjustment of the body clock. Sleep loss and its effects are important components of jet lag, and attempts to promote sleep by the use of melatonin and other hypnotics are also relevant. Sleep loss is also found in those who undertake challenges that involve long periods where the normal consolidated sleep of 8 h length is not possible. Advice on sleep regimens in such circumstances is given.

Adaptation, Physiological↗
PubMed2004

The isolated and combined effects of menstrual cycle phase and time-of-day on muscle strength of eumenorrheic females.

Diurnal variation in muscle performance has been well documented in the past few years, but almost exclusively in the male population. The possible effects of the menstrual cycle on human circadian rhythms have remained equivocal, particularly in the context of muscle strength. The purpose of the study was to analyze the isolated and combined effects of circamensal variation and diurnal changes on muscle strength. Eight eumenorrheic females (age 30 +/- 5 yrs, height 1.63 +/- 0.06m and body mass 66.26 +/- 4.6kg: mean +/- SD) participated in this investigation. Isokinetic peak torque of knee extensors and flexors of the dominant leg were measured at 1.05, 3.14rad.s(-1) (through 90 degrees ROM) at two times-of-day (06:00, 18:00 h) and five time points of the menstrual cycle (menses, mid-follicular, ovulation, mid-luteal, late luteal). In addition, maximum voluntary isometric contraction of knee extensors and flexors and electrically stimulated isometric contraction of the knee extensors were measured at 60 degrees of knee flexion. Rectal temperature was measured during 30min before the tests. There was a significant time-of-day effect on peak torque values for isometric contraction of knee extensors under electrical stimulation (P< 0.05). At 18:00 h, muscle force was 2.6% greater than at 06:00 h. The time-of-day effect was not significant when the tests were performed voluntarily without stimulation: effect size calculations indicated small differences between morning and evening for maximal voluntary isometric contraction and peak torque (at 1.05rad.s(-1) for the knee extensors. A circamensal variation was observed for peak torque of knee flexors at 1.05rad.s(-1), extensors at 3.14rad.s(-1), and also isometric contraction of knee flexors, values being greatest at the ovulation phase. Interaction effects between time-of-day and menstrual cycle phase were not observed in any of the indices of muscle strength studied. The phase of the menstrual cycle seemed to have a greater effect than did the time-of-day on female muscle strength in this group of subjects. The present results suggest that peripheral rather than central mechanisms (e.g., motivation) are implicated in the diurnal variation of maximal isometric strength of women.

Adult↗
PubMed2004

A school-based survey of recurrent non-specific low-back pain prevalence and consequences in children.

The aim of this investigation was to provide evidence of the prevalence and consequences of recurrent low-back pain in children from Northwest England. A cross-sectional survey was conducted involving a standardized questionnaire with established reliability and validity. A cross-sectional sample of 500 boys (n = 249) and girls (n = 251) aged between 10 and 16 years participated in the study. Average lifetime prevalence of low-back pain was 40.2% [95% confidence interval (CI) = 38.7-41.6]. Most cases of low-back pain were acute episodes that did not lead to disabling consequences. In contrast, 13.1% (95% CI = 12.5-13.7) experienced recurrent low-back pain that led to disabling consequences; 23.1% visited a medical practitioner, 30.8% experienced loss of physical activity/sports and 26.2% had been absent from school because of low-back pain. Recurrent low-back pain was particularly evident during late adolescence where one in five children were cases. The health education implications of low-back pain in children are discussed. It was concluded that low-back pain is a common complaint during childhood, although most cases are acute episodes that represent little health consequence. In contrast, some children experience recurrent low-back pain that can lead to disabling consequences. Future research should focus on recurrent low-back pain cases since they often led to disabling consequences.

Adolescent↗
PubMed2003

Effect of menstrual cycle phase on the concentration of bioavailable 17-beta oestradiol and testosterone and muscle strength.

To investigate the effect of changes in sex hormone concentration on muscle strength and the bioavailability of 17-beta oestradiol (oestradiol) and testosterone, seven eumenorrheic females were tested during two phases of the menstrual cycle. Maximum voluntary isometric strength of the first dorsal interosseus muscle was measured during the early follicular and mid-luteal phases of the menstrual cycle. These phases were chosen for testing as the concentration of total oestradiol is significantly different in these two phases. Total oestradiol has been repeatedly associated with changes in muscle strength in females, whereas the effects of bioavailable oestradiol are unknown. The concentrations of total and bioavailable oestradiol and testosterone were measured in addition to the concentration of total progesterone. Concentrations of total progesterone and oestradiol were significantly different between the early follicular and mid-luteal phases of the menstrual cycle (P <0.05 and P <0.001 respectively). The concentration of total testosterone (0.7+/-0.2 and 0.8+/-0.1 nmol.l(-1) respectively) and the ratio of total oestradiol to progesterone (153.0+/-251.2 and 108.5+/-27.8 respectively) did not change significantly between the early follicular and mid-luteal phases. Bioavailable testosterone (102.2+/-66.3 and 105.0+/-90.2 pmol.l(-1) respectively) and bioavailable oestradiol (90.5+/-35.5 and 120.0+/-60.6 pmol.l(-1) respectively) did not differ significantly between phases. There were no significant differences in muscle strength during the menstrual cycle (P =0.1). Mean maximum voluntary isometric force of the first dorsal interosseus muscle did not correlate significantly with the mean concentration of any reproductive hormone measured. These results indicate that cyclical variation in endogenous reproductive hormones does not affect muscle strength.

Adult↗
PubMed2003

Physiological, subjective and performance effects of pseudoephedrine and phenylpropanolamine during endurance running exercise.

The aim of the study was to assess the effect of maximal therapeutic dosing of sympathomimetic amines found in over-the-counter (OTC) decongestant preparations on endurance running. Following familiarisation and a graded exercise test to determine maximal oxygen uptake (VO2 max), trained male runners (n = 8) completed four exercise sessions each separated by a minimum of one week. Each session was comprised of 20 min of sub-maximal treadmill running (70 % VO2 max) followed by a 5,000-m time trial on the treadmill under drug, placebo or control conditions. Drugs were administered in their commercial format over the 36-hour period prior to testing in the manufacturer's recommended maximal doses (i. e. 25 mg of phenylpropanolamine and 60 mg of pseudoephedrine four times daily). During sub-maximal endurance running no statistical differences were observed in heart rate, VO2, minute ventilation, respiratory exchange ratio, blood lactate, glucose or non-esterified fatty acids (NEFA) or ratings of perceived exertion with respect to the treatment administered. Similarly there were no statistical differences according to the condition during the 5,000-m running time trial, in terms of heart rate, ratings of perceived exertion, time of completion and pre and post exercise blood lactate, glucose or NEFA. The results indicate that in maximal, multiple therapeutic doses both pseudoephedrine or phenylpropanolamine as present in common OTC decongestant formulations do not affect, nor possess any ergogenic properties with regard to, endurance running.

Adult↗