Biomedical subjects

T Reilly

Publications and source records attributed to T Reilly.

At least 37 records · Page 2Linked to original sources

PubMed1997

The quality of health data obtained in a new survey of elderly Americans: a validation study of the proposed Medicare Beneficiary Health Status Registry (MBHSR).

The Medicare Beneficiary Health Status Registry (MBHSR) is a proposed new survey program that would collect health status indicators annually from large probability samples of Medicine beneficiaries. For reasons of economy, the MBHSR would use mail survey procedures with telephone follow-up of nonrespondents. Because of concerns about response rates and the validity and reliability of the data obtained by such methods, a large-scale (N = 1,922) field test was conducted. The field test assessed the validity of MBHSR survey reports of past medical treatment and conditions by comparing those reports with Medicare claims data. It assessed the (internal) reliability of MBHSR survey responses by comparing responses with logically related survey questions from the MBHSR. Analyses indicate that the MBHSR survey procedures using a combination of mail data collection with telephone follow-up of nonrespondents produced relatively high levels of sensitivity and specificity in identifying medical treatments and procedures previously recorded in Medicare claims data. In addition, the MBHSR Field Test obtained, in general, relatively high levels of internal consistency in survey reports.

Aged↗

PubMed1997

Aging, rhythms of physical performance, and adjustment to changes in the sleep-activity cycle.

OBJECTIVES: Shiftwork causes disturbances of the normal sleep-wake cycle and circadian rhythm. There is concern that aging workers have more problems than younger counterparts when the human body clock is disrupted. This review considers issues relating to aging, the circadian body clock, and adjustment to altered sleep-wake schedules. METHODS: Reports on effects of aging on the human body clock were reviewed. Research concerned with adjustment to circadian phase shifts (as occurs in night work) was considered. RESULTS: With aging there is an increased tendency towards morningness which is linked with difficulties in sleeping. The peak time and amplitude of normal circadian rhythms are altered. Tolerance of shiftwork can be linked with social factors as well as adaptation of the body clock. CONCLUSIONS: People habituated to night work seem to have developed mechanisms which allow them to cope with disruptions to lifestyle and the endogenous body clock. Elderly people are more suited to phase advances, as occur in morning workshifts, than to phase delays such as nocturnal work.

Adult↗

PubMed1997

The effect of eumenorrheic menstrual cycle phase on physiological responses to a repeated lifting task.

Cyclic variations in physiological and endocrinological baselines are known to be consistent with the eumenorrheic (healthy) menstrual cycle. The aim of this study was to examine the interaction of these variations with the physiological responses to repeated lifting. Sixteen females visited the laboratory in each of five phases of their menstrual cycle. During each visit, subjects performed a repetitive lifting task, lifting a weighted box, from knee to shoulder height, at six repetitions per minute for 10 min. Oxygen consumption, minute ventilation, heart rate (HR), and perceived exertion were monitored throughout the task. The variation in physiological and subjective responses to lifting with menstrual cycle phase did not reach statistical significance (p > .05). However, the HR response to lifting was elevated by approximately 10 beats x min-1 in the postovulatory phases of the cycle (effect size > 0.61). Although the impact of the menstrual cycle upon lifting performance is minimal, alterations in HR must be taken into account in determining new international standards for manual handling.

Adolescent↗

PubMed1997

Physiological and biomechanical aspects of orienteering.

Orienteering is an endurance running event which differs from other running sports both in its cognitive element and in the type of terrain encountered. The demands of overcoming this terrain are not manifest in significant differences between orienteers and road runners in somatotype, though elite female orienteers have consistently been shown to have higher levels of adiposity (> 19%) than elite road runners. High aerobic power in orienteers (up to 63 and 76 ml/kg/min in women and men, respectively) is coupled with lower anaerobic performance. While leg strength is generally not high when compared with other athletic specialties, female orienteers have relatively good leg flexion strength. The energy cost of running is greatly increased in rough terrain. Oxygen cost was 26% higher while running in a forest when compared with road running. Biomechanical differences in stride pattern contribute towards this increased demand. Despite the high energy demands during competition, orienteers pace themselves such that their mean heart rate remains within the range of 167 to 172 beats/min, despite large fluctuations. The rough terrain encountered in orienteering results not only in a high energy cost but also in a higher incidence of sport-specific injuries, particularly to the ankle. Minor injuries such as cuts and bruises are common during competition.

Anthropometry↗

PubMed1996

Effects of active warm-down and carbohydrate feeding on free fatty acid concentrations after prolonged submaximal exercise.

We examined the effects of active warm-down (AWD) and carbohydrate ingestion on plasma levels of free fatty acids (FFAs) and glucose changes into recovery following prolonged submaximal exercise. Subjects in Group 1 cycled at 70% of maximal oxygen uptake (VO2max); carbohydrate (CHO) or placebo (PLA) was ingested 15 min before and 45 min during exercise. In the AWD experiment, exercise was followed immediately by an AWD and subjects were given a placebo solution. Group 2 subjects consumed CHO or PLA at 75 min during and after exercise at 70% VO2max. ANOVA revealed a significant decrease in blood glucose levels only in Group 1, with a concomitant increase in FFA concentrations during exercise in both groups. Carbohydrate ingestion in Groups 1 and 2 significantly decreased the normal response of FFAs during exercise and markedly reduced the normal elevation of FFAs in recovery. AWD following submaximal exercise had no effect on plasma FFA elevations in recovery. These results suggest that carbohydrate ingestion, but not active warm-down, attenuates FFA elevations in recovery.

Adult↗

PubMed1996

The biochemical pathway mediating the proliferative response of bone cells to a mechanical stimulus.

Calvarial bone cells of rats were subjected to either a cyclic biaxial strain of 0.17 per cent (1700 microstrain) or a hydrostatic pressure of 2.5, five, or ten pounds per square inch (17.2, 34.5, or sixty-nine kilopascals). The frequency was held constant at one hertz for both types of mechanical stimulation. When cultured bone cells that had been subjected to a cyclic biaxial strain for two hours were harvested twenty-two hours later, it was found that the level of prostaglandin E2 had increased significantly (p < 0.01) as had cellular proliferation (p < 0.01), as indicated by the incorporation of [3H]-thymidine. The addition to the medium of indomethacin, an inhibitor of prostaglandin synthesis, at a ten-micromolar concentration significantly inhibited (p < 0.01) the increase in prostaglandin E2 synthesis but had no effect on the strain-induced increase in cellular proliferation, as indicated by the incorporation of [3H]-thymidine. Twenty-four hours after exposure to the same cyclic biaxial strain for thirty seconds, other cultured bone cells showed a significant increase in the level of cytoskeletal calmodulin (p < 0.05) and in the DNA content (p < 0.05). N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7), a calmodulin antagonist, was added to the medium at a one-micromolar concentration, which had been shown to have no effect on the increase in the DNA content of control cells; W-7 completely blocked the increase in the level of cytoskeletal calmodulin and in the DNA content in the cells that were subjected to a cyclic biaxial strain. The bone cells subjected to a hydrostatic pressure showed a dose-dependent increase in the concentration of cytosolic Ca2+, as measured with Fura 2-AM, a fluorescent indicator of intracellular calcium. With a pressure of ten pounds per square inch (sixty-nine kilopascals), the increase in the concentration of cytosolic Ca2+ was nearly eight times greater than that at 2.5 pounds per square inch (17.2 kilopascals) (126 +/- 15.2 compared with 16 +/- 8.0 nanomolar, mean and standard deviation). The addition to the medium of neomycin, an inhibitor of the inositol phosphate cascade, at a ten-millimolar concentration completely blocked the increase in the concentration of cytosolic Ca2+ in these cells; this concentration of neomycin had been shown to have no effect on proliferation in control bone cells. There was also a dose-dependent relationship between the duration of the stimulus and the cellular proliferation. Remarkably, one cycle of pressure at ten pounds per square inch (sixty-nine kilopascals) and a frequency of approximately one hertz produced a 57 per cent increase in the incorporation of [3H]-thymidine at twenty-four hours (p < 0.001). From these findings, we hypothesized that the inositol phosphate cascade-cytosolic Ca(2+)-cytoskeletal calmodulin system plays a dominant role in the signal transduction of a mechanical stimulus into increased proliferation of bone cells, at least under the conditions reported here.

Animals↗

PubMed1996

Circadian variation in sports performance.

Chronobiology is the science concerned with investigations of time-dependent changes in physiological variables. Circadian rhythms refer to variations that recur every 24 hours. Many physiological circadian rhythms at rest are endogenously controlled, and persist when an individual is isolated from environmental fluctuations. Unlike physiological variables, human performance cannot be monitored continuously in order to describe circadian rhythmicity. Experimental studies of the effect of circadian rhythms on performance need to be carefully designed in order to control for serial fatigue effects and to minimise disturbances in sleep. The detection of rhythmicity in performance variables is also highly influenced by the degree of test-retest repeatability of the measuring equipment. The majority of components of sports performance, e.g. flexibility, muscle strength, short term high power output, vary with time of day in a sinusoidal manner and peak in the early evening close to the daily maximum in body temperature. Psychological tests of short term memory, heart rate-based tests of physical fitness, and prolonged submaximal exercise performance carried out in hot conditions show peak times in the morning. Heart rate-based tests of work capacity appear to peak in the morning because the heart rate responses to exercise are minimal at this time of day. Post-lunch declines are evident with performance variables such as muscle strength, especially if measured frequently enough and sequentially within a 24-hour period to cause fatigue in individuals. More research work is needed to ascertain whether performance in tasks demanding fine motor control varies with time of day. Metabolic and respiratory rhythms are flattened when exercise becomes strenuous whilst the body temperature rhythm persists during maximal exercise. Higher work-rates are selected spontaneously in the early evening. At present, it is not known whether time of day influences the responses of a set training regimen (one in which the training stimulus does not vary with time of day) for endurance, strength, or the learning of motor skills. The normal circadian rhythms can be desynchronised following a flight across several time zones or a transfer to nocturnal work shifts. Although athletes show all the symptoms of 'jet lag' (increased fatigue, disturbed sleep and circadian rhythms), more research work is needed to identify the effects of transmeridian travel on the actual performances of elite sports competitors. Such investigations would need to be chronobiological, i.e. monitor performance at several times on several post-flight days, and take into account direction of travel, time of day of competition and the various performance components involved in a particular sport. Shiftwork interferes with participation in competitive sport, although there may be greater opportunities for shiftworkers to train in the hours of daylight for individual sports such as cycling and swimming. Studies should be conducted to ascertain whether shiftwork-mediated rhythm disturbances affect sports performance. Individual differences in performance rhythms are small but significant. Circadian rhythms are larger in amplitude in physically fit individuals than sedentary individuals. Athletes over 50 years of age tend to be higher in 'morningness', habitually scheduling relatively more training in the morning and selecting relatively higher work-rates during exercise compared with young athletes. These differences should be recognised by practitioners concerned with organising the habitual regimens of athletes.

Circadian Rhythm↗

PubMed1996

Effects of nocturnal shiftwork on mood states of student nurses.

Daily mood changes were monitored over successive 24-h periods using the Profile of Mood States (POMS) (3) to assess the effect of nocturnal shiftwork on mood. Twenty-three student nurses, age range 19-24 years, were studied throughout their first experience of nocturnal shiftwork. The POMS was administered over four complete solar days during a 12-week period that included an 8-week block of night work. Five POMS dimensions displayed circadian rhythmicity: vigor-activity; fatigue-inertia; confusion-bewilderment; friendliness; and total-mood-disturbance. These five dimensions were sensitive to changes in living patterns, showing phase shifts in their circadian rhythms when subjects alternated between diurnal and nocturnal living patterns. The dimensions were also observed to be sensitive to adjustment to two different nocturnal shiftwork schedules. The subjects who worked "four on, three off" showed similar phase shifts to the subjects who worked "eight on, seven off," suggesting that mood adjustment takes place by the fourth night of a rotation of nights. The "commitment" of the students to the nocturnal living pattern was thought to have a bearing on the adaptation of the students to the nocturnal shifts, as regards mood.

Adaptation, Psychological↗

PubMed1995

Prominent expression of bFGF in dorsal root ganglia after axotomy.

Using quantitative in situ hybridization and immunohistochemistry the expression of acidic and basic fibroblast growth factors (aFGF, bFGF) in dorsal root ganglia (DRGs) was examined. Around 5% of the small neurons expressed bFGF mRNA in normal DRGs. Nerve injury induced a very dramatic and rapid up-regulation in bFGF mRNA levels, and around 80% of all DRG neurons expressed bFGF mRNA 3 days after axotomy. A distinct increase in bFGF-like immunoreactivity (LI) was also detected as early as 15 h after axotomy. The elevation of bFGF mRNA and protein levels declined after 1 week. bFGF mRNA was also up-regulated in non-neuronal cells following axotomy. Normally bFGF-LI was mainly localized in the nuclei of DRG neurons and in some non-neuronal cells. After nerve section, bFGF-LI was in addition found in the cytoplasm, and many more bFGF-positive non-neuronal cells were observed. By means of confocal microscopy analysis of axotomized DRGs, some bFGF-LI could be detected in vesicle-like structures in the cytoplasm as well as in the nucleoli, in addition to the nuclear location. Application of leukaemia inhibitory factor to the transected sciatic nerve significantly increased the number of bFGF-positive neurons, whereas the bFGF-LI in non-neuronal cells was strongly suppressed. About 70% of the normal DRG neurons expressed aFGF mRNA and aFGF-LI. Axotomy produced a moderate increase in aFGF mRNA levels, but no detectable effect on protein levels. Taken together, the results show that bFGF may be involved in the neuronal response to injury and suggest a role in neuronal survival and regeneration in axotomized DRG neurons.

Animals↗

PubMed1995

Epidemiological aspects of back pain: the incidence and prevalence of back pain in nurses compared to the general population.

Two studies using retrospective questionnaires were conducted to obtain epidemiological information from nursing personnel (n = 1134) and among an age- and gender-matched cross-section of the general population (n = 315). The point and annual prevalence of back pain did not differ between the two sample groups. Nurses demonstrated a greater annual incidence of back pain (14.7%, compared to 11.5% in non-nurses). The point prevalence of back pain increased with age in both sample groups. Nurses considered patient-handling tasks instrumental in the onset of back pain symptoms. Comparison of results with those obtained from a similar study published in 1983 indicated an increase of almost 40% in the prevalence of back pain symptoms in nurses, although the linearity of the rise was not ascertained. The implementation of guidelines on the manual handling of loads has led to revised training procedures and these may have influenced the epidemiological findings.

Adolescent↗

PubMed1995

The physiological demands of Gaelic football.

Match-lay demands of Gaelic football and fitness profiles were assessed at club competitive level. English Gaelic football club championship players (n = 11) were assessed for anthropometry, leg strength and time to exhaustion on a treadmill run. A similar test battery was administered to a reference group of University competitive soccer players (n = 12). Heart rate was recorded during match-play using radio telemetry and blood lactate concentrations were determined at half-time and after full-time. No differences (p > 0.05) were observed between the Gaelic and soccer players in: body mass (70.7 +/- 10.3 vs 76.6 +/- 10.3 kg); height (176 +/- 5.9 vs 177.7 +/- 6.4 cm); leg to trunk ratio (0.53 +/- 0.01 vs 0.54 +/- 0.03); adiposity (12.2 +/- 2.1 vs 13.5 +/- 3.2% body fat); mean somatotype (2.8 - 4.3-2.0 vs 2.4-4.2-2.4); leg strength measures; and performance on the treadmill. The percentage muscle mass values were lower for the Gaelic players compared to the soccer players (41.9 +/- 5.4 vs 47.3 +/- 5.2%; p > 0.005). For the Gaelic and soccer players, respectively, mean heart rate recorded during each half of match-play were (157 +/- 10 and 158 +/- 12 beats/min) and (164 +/- 10 and 157 +/- 11 beats/min), whilst blood lactates measured at the end of each half, were (4.3 +/- 1 and 3.4 +/- 1.6 mmol/l) and (4.4 +/- 1.2 and 4.5 +/- 2.1 mmol/l). Gaelic footballers at English club championship level seem to exhibit similar fitness profiles, and are subject to broadly similar physiological demands as University-level competitive soccer players.

Adult↗

PubMed1995

Effects of age and time of day on preferred work rates during prolonged exercise.

This study was designed to examine the effects of age and time of day on work rates during prolonged, self-paced exercise. Eight young (19-25 years of age) and eight old (48-62 years of age) endurance athletes volunteered for the study. At two times of day (07:00 and 17:00 h), subjects were asked to pedal on a Monark cycle ergometer (Varberg, Sweden) at a self-chosen exercise intensity that they believed they could sustain for exactly 80 min. This self-chosen work rate, rectal temperature, skin temperature (chest, arm, and lower leg), oxygen consumption (VO(2)), expired carbon dioxide (VCO(2)), minute ventilation (VE), heart rate, and perceived exertion (RPE) were recorded every 10 min during the exercise. Preexercise resting measures of rectal temperature, VO(2), and VE were less affected by the time of day in the older group than were those in the young subjects (p<0.05). In the morning, rectal temperature was 0.3 degrees C higher in the older subjects than in the young adults. Diurnal variation in mean work rate over the 80-min exercise period was not evident in the old group (p>0.10) but amounted to 10 W in the young group (p<0.05). Older subjects chose work rates 5.4 W lower than did the young subjects in the morning test session (p>0.10). In the afternoon, age differences in work rate amounted to 14.3 W (p<0.05). For all subjects, work rates remained relatively constant throughout the exercise period in the morning. In the afternoon, subjects chose high work rates within the first 40 min of exercise, after which work rate decreased sharply to values similar to those recorded in the morning (p<0.01). These changes were mirrored closely by changes in (VO(2)) and VCO(2). Perceived exertion increased linearly throughout exercise, irrespective of age or time of day. These results suggest that, in young adults, the mean work rate over 80 min of exercise is higher in the afternoon than in the morning, although the work rate decreased sharply toward the end of the afternoon exercise. In agreement with studies reporting age-related increases in "morningness," age differences in work rate appeared to be least when exercise was performed in the morning.

Adult↗

PubMed1995

A multivariate analysis of kinanthropometric profiles of elite female orienteers.

The purpose of this study was to examine the relevance of various kinanthropometric features of elite female orienteers in terms of success at the Student World Orienteering Championships (SWOC)(1992). Participants at this competition were divided into successful (final placing in top 35; n = 12) and less successful (final placing below 35; n = 11) competitors. A non-orienteering reference group was used to enable the identification of any sport specific factors. Measurements of the orienteering group were taken during the week of the SWOC and included 5 skinfold thicknesses, 2 limb girths, 2 bone breadths, 3 proportional lengths and 3 physical tests (grip strength, leg strength, flexibility). Using the results of these, percent adiposity, somatotypes and various anthropometric indices were also obtained. Age and adiposity variables were found to correlate significantly with competitive performance (p < 0.01). Discriminant function analysis successfully distinguished between the successful and less successful orienteers (Wilks' Lambda = 0.603; p < 0.01). There was no difference (p > 0.05) between the orienteering group and the reference group for the majority of the proportionality measures and similarily in the results of the physical tests. Adiposity values were higher in the non-orienteers. In conclusion, body composition measures discriminated between successful and less successful orienteers at a major event at an elite level. The primary difference between the orienteers and the reference group was in body composition rather than linear or proportional measures.

Adipose Tissue↗

PubMed1995

Effects of time of day on self-paced performances of prolonged exercise.

Pre-exercise body temperature varies throughout the day due to its circadian rhythm. This study aimed to compared responses to sustained exercise in the morning and in evening. Rectal temperature was measured pre-exercise and throughout a 60 min test on a cycle ergometer against a fixed frictional resistance in seven males (aged 19-24 years). The subjects were instructed to work as hard as possible over the entire exercise period but could vary the pedal frequency at any time. Power output was calculated by computer, utilising an optical detection device to monitor flywheel revolutions. Tests were performed at 08:30 and 17:30 h, balanced for order with at least 72 hours between tests. Rectal temperature was lower pre-exercise in the morning (37.2 degrees C) than at evening (37.8 degrees C). This differences was reduced to 0.3 degrees C by the end of exercise. Mean power output was similar for the two times of day for the whole exercise period. A higher power output in the evening over the first half of the test was compensated for by a greater performance in the morning over the second 30 min (p < 0.05). It seems that the pacing of endurance performance is affected in the morning, but without any overall effect at least for the duration examined and at the ambient environmental temperature of 17-19 degrees C.

Adult↗

PubMed1994

Hormonal and metabolite responses to glucose and maltodextrin ingestion with or without the addition of guar gum.

The purpose of this study was to examine the effects of ingesting water (P), a glucose solution (GL), a maltodextrin solution (Md), a glucose solution with 8% guar gum (GL+G), and a maltodextrin solution with 8% guar gum (Md+G), on the hormonal and metabolite responses during cycling, and on subsequent time to exhaustion. Five male subjects undertook five 90 min rides on a bicycle ergometer at an exercise intensity corresponding to 65% VO2max after having ingested 1 g.kg-1 body weight of the test product in 400 ml of water immediately before the exercise. Blood samples were taken during the trials for analyses of adrenaline, noradrenaline, insulin, glucagon, glucose, lactate and non-esterified fatty acids (NEFA). Respiratory measures were also undertaken during the trials for the determination of oxygen consumption (VO2) and respiratory exchange ratio (RER), from which the carbohydrate oxidation rates were calculated. Rates of perceived exertion (RPE) were also assessed. Ten minutes after the 90 min ride, subjects exercised to volitional exhaustion at an exercise intensity of 75% VO2max. ANOVA revealed that there were significant differences between the treatments for adrenaline (p < 0.01), insulin (p < 0.05), glucose (p < 0.01), lactate (p < 0.01), NEFA (p < 0.01), RER (p < 0.001) and carbohydrate oxidation rate (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Sources of variation in back and leg dynamometry.

Three investigations were carried out to examine the concurrent validity and the reliability of a portable dynamometer (Takei Kiki Kogyo) for the measurement of back and leg strength. First, leg extension strength of 19 subjects was measured using the Takei dynamometer and compared to the isometric knee extension strength of the dominant (right) leg measured using a computer-controlled dynamometer (Lido Active, Davis, CA). The back extension strength of 18 subjects was also compared between the two dynamometers. Second, back and leg strengths of 36 subjects, aged 19-30 years, were measured twice using the Takei dynamometer. Six days separated the test and retest. Third, back and leg strengths of four subjects, aged 21-30 years, were measured at six different times of the solar day. Significant relations (p < 0.001) were obtained between the Takei and Lido dynamometers for leg strength (r = 0.90) and back strength (r = 0.79). Significant test-retest correlations (p < 0.001) were found for leg strength (r = 0.80) and back strength (r = 0.91). Group mean (+/- SD) leg strength values of test (1450.4 +/- 428.6 N) and retest (1432.8 +/- 449.1 N) did not differ ((p > 0.05). A small (4.5%) but significant difference was found between the test (1057.2 +/- 309.9 N) and retest (1106.2 +/- 334.4 N) mean values for back strength (p < 0.05). A time of day effect was evident for back and leg strength (p < 0.05); on average the peak times occurred at 16:53 h and 18:20 h, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

The relation between isometric lifting strength and muscular fitness measures.

The purpose of this study was to construct an isometric lift dynamometer and relate isometric lifting strength to dynamic measures of muscular fitness, leg and back strength and muscular power output. Thirty-one male subjects, aged 19-24 years, performed a standing broad jump (for distance), a vertical jump (for flight time), 3 maximal pulls (for peak power) on a rowing ergometer and maximal isometric leg and back extensions on a conventional dynamometer. The results of these tests were correlated with the maximum isometric lifting strength (MILS) obtained on the lift dynamometer using cluster correlation and multiple regression. Significant correlations (p < 0.001) were found between isometric lifting strength and back strength (BS) (r = 0.59), and leg strength (LS) (r = 0.74). A significant correlation was also noted between isometric lifting strength and both standing broad jump (SBJ) (r = 0.58, p < 0.001) and power output (PO) (r = 0.38, (p < 0.05). Multiple regression analysis was used to predict lifting performance from a battery of standard fitness tests. The prediction equation for maximal isometric lifting strength included the terms LS, BS, SBJ and PO (r = 0.80). The relation between isometric lifting strength and other muscular fitness variables suggest that the method used provides an acceptable measure of strength and an indication of the involvement of back and leg musculature in squat lifting.

Adult↗

PubMed1994

The effect of partial sleep deprivation on weight-lifting performance.

This study examined the effects of partial sleep deprivation on submaximal and maximal weight-lifting tasks and on subjective states pre- and post-activity. Eight male subjects (aged 18-24 years) were restricted to a nightly ration of 3 h sleep for 3 successive nights after baseline measures on the first day. A 4 day period where normal sleep was permitted fulfilled a control condition, the normal and sleep-deprived conditions being counterbalanced and separated by 10 days. The weight-lifting tasks consisted of biceps curl, bench press, leg press, and dead lift. For each exercise a submaximal load, corresponding to a fixed value on a category ratio scale of exertion, was determined for 20 repetitions; the maximal lift for that exercise was then obtained. A profile of mood states and subjective sleepiness were determined at each test occasion, tests being conducted in the evening of each day. There was no significant effect of sleep loss on performance of maximal biceps curl (p < 0.05) but a significant effect was noted on maximal bench press, leg press, and dead lift (p < 0.001). Trend analysis indicated decreased performance in submaximal lifts for all the 4 tasks: the deterioration was significant after the second night of sleep loss (p < 0.01). Performing the lifts had little influence on sleepiness ratings which increased linearly with successive days of sleep loss. Mood states of confusion, vigour, and fatigue were affected significantly by the sleep deprivation regimen (p < 0.001), but there was no significant effect of sleep loss or anger, tension, and depression (p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗