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Biomedical subjects

M I Lambert

Publications and source records attributed to M I Lambert.

At least 37 records · Page 2Linked to original sources
PubMed2000

Changes in muscle power and neuromuscular efficiency after a 40-minute downhill run in veteran long distance runners.

OBJECTIVE: To establish whether there was a relationship between the total accumulated distances of racing in veteran runners and the neuromuscular efficiency of the quadriceps muscles before and after a downhill run. SETTING: University of Cape Town, Sports Science Institute of South Africa. PARTICIPANTS: Twenty male veteran long distance runners (45-50 years of age) with a range of training (1,300 km to 111,280 km) and racing (0 km to 9,737 km) experience. INTERVENTION: A 40-minute downhill run (-10% decline) on a treadmill, at a speed corresponding to 70% of the subject's peak treadmill running speed. MAIN OUTCOME MEASURES: The difference between integrated electromyography (IEMG)/mean force over a 5 s maximal voluntary isometric contraction before and after the downhill run was calculated as the delta (delta) neuromuscular efficiency. This was related to the total kilometers trained, current training distance, total kilometers raced, and number of races > 56 km. The difference in drop jump height before and after the downhill run was measured as well as changes in heart rate throughout the run. RESULTS: There was a significant curvilinear relationship between the delta neuromuscular efficiency and total kilometers raced (R2 = 0.53, p < 0.05), and a significant inverse relationship between delta neuromuscular efficiency and the number of races > 56 km (r = -0.50, p < 0.05). Drop jump height decreased after the downhill run, and heart rate increased during the run. CONCLUSIONS: Runners who have raced an accumulated distance of > 5,000 km show a significant dissociation in the delta neuromuscular efficiency after a downhill run, compared with less experienced runners. Although possible causes for the dissociation are discussed, further research is needed.

Anthropometry↗
PubMed2000

Quadriceps and hamstrings peak torque ratio changes in persons with chronic anterior cruciate ligament deficiency.

STUDY DESIGN: Cross-sectional analytical study in which subjects served as their own controls. OBJECTIVE: To assess the concentric and eccentric peak torque in the hamstrings and quadriceps muscles, hamstrings/quadriceps amplitude ratios, and lean thigh volume differences in the involved and uninvolved limb of subjects with anterior cruciate ligament (ACL) deficiency. BACKGROUND: [corrected] Although the hamstrings/quadriceps ratios for concentric and eccentric activity have been studied, the more functional eccentric hamstings/concentric quadriceps ratio has not been previously described in chronic ACL deficient individuals. METHODS AND MEASURES: Eighteen subjects (36 +/- 11 years; 12 men, 6 women) with unilateral chronic ACL deficiency were recruited. Changes in activities of daily living, lean thigh volume (LTV) and isokinetic peak torque and total work capacity of both the quadriceps and hamstring muscles were investigated. The uninvolved limb served as control. RESULTS: Eccentric quadriceps peak torque in the ACL deficient limb was reduced by 38% compared with the 16% reduction of concentric quadriceps peak torque. Eccentric hamstrings peak torque was reduced by 15% compared with an 8% reduction in concentric hamstrings peak torque. LTV in the ACL deficient limb was 11% smaller than the uninvolved limb (3,541 +/- 899 vs 3,161 +/- 742 cc, uninvolved versus ACL deficient limb). The relation between LTV and eccentric peak torque was stronger in the uninvolved (r = 0.82) compared with the ACL deficient limb (r = 0.66). The eccentric hamstrings/quadriceps ratio was significantly higher in the ACL deficient (0.80 +/- 0.26) compared with the uninvolved limb (0.55 +/- 0.13). However, the eccentric hamstrings/concentric quadriceps ratio was similar between ACL deficient (0.75 +/- 0.17) and uninvolved (0.77 +/- 0.20) limbs, while the concentric hamstrings/eccentric quadriceps ratio was significantly higher in the ACL deficient (0.79 +/- 0.26) compared with the uninvolved (0.50 +/- 0.14) limb. CONCLUSIONS: Quadriceps and hamstrings peak torque values were significantly decreased in ACL deficient compared with the uninvolved limb. Eccentric muscle activity was affected to a greater degree than concentric muscle activity in the quadriceps muscle after ACL injury. The eccentric hamstrings/concentric quadriceps ratios were similar in ACL deficient and normal limbs, indicating that muscular co-ordination strategies may have been altered to maintain normal limb activity despite the strength losses particularly evident in quadriceps muscle function.

Adult↗
PubMed2000

Veteran athletes exercise at higher maximum heart rates than are achieved during standard exercise (stress) testing.

OBJECTIVE: The stress electrocardiogram (sECG) is routinely used to screen individuals for underlying cardiac pathology before an exercise programme is prescribed. The underlying assumption is that the cardiac responses elicited during the sECG test are similar to those achieved during participation in sporting activities. However, this premise may be incorrect since the physical demands of different modes of exercise vary substantially. DESIGN: Ten veteran league squash players (LSP), 10 social squash players (SSP), 10 league runners (LR), 10 social runners (SR) and 10 sedentary individuals (SED) were recruited for the study. All subjects completed a lifestyle questionnaire, a full medical examination and a routine sECG. Thereafter each subject's heart rate (HR) was monitored on two separate occasions while participating in sporting activity. RESULTS: No sECG exercise-induced abnormalities were observed, although five subjects showed resting abnormalities. Maximal HR during the sECG, and maximal and mean HR during the field tests, were not significantly different between groups. However, maximal HR was significantly higher in all groups during their sporting activities than during stress testing in the laboratory (P < 0.01). CONCLUSIONS: Maximal HR in veteran athletes during specific sporting activities was significantly higher than that attained during a routine sECG. This finding was not sport-specific, nor was it related to the level of competitiveness of the trial participants. These data show that a routine sECG is a submaximal test of exercise performance, and should be interpreted as such.

Blood Pressure Determination↗
PubMed1999

The effect of a prophylactic dose of flurbiprofen on muscle soreness and sprinting performance in trained subjects.

The aim of this study was to examine the effects of a prophylactic dose of a local, transcutaneously administered, non-steroidal anti-inflammatory drug on muscle soreness, muscle damage and sprinting performance in young trained males. Twenty-five subjects aged 19+/-3 years, actively participating in rugby union and field hockey, were familiarized with the test procedure and then divided at random into an experimental group (n = 13) and a control group (n = 12). The experimental group received two patches, each containing 40 mg flurbiprofen (TransAct LAT), 12 h before an exercise bout designed to produce delayed-onset soreness (DOMS). The control group received identical non-medicated placebo patches at the same time. Delayed-onset muscle soreness was induced by an exercise protocol consisting of drop jumps (seven sets of 10 repetitions). Serum creatine kinase activity, muscle soreness, muscle girth and acceleration in a maximal sprint over 30 m were measured before the induction of DOMS and at 12, 24, 48 and 72 h thereafter. Plasma lactate concentration was measured 3 min after the 30-m sprint tests. Subjects in both groups had significantly more pain at 24 and 48 h compared with at 12 and 72 h (P < 0.05; Friedman two-way analysis of variance). Thigh girth and serum creatine kinase did not change throughout the experiment. Although plasma lactate concentrations were elevated after the 30-m sprint, there were no differences between groups or as a result of DOMS. The greatest acceleration occurred between 5 and 10 m. This was not affected by the anti-inflammatory drug or DOMS. In conclusion, the aetiology of the DOMS induced in the trained subjects in this study seems to be independent of inflammatory processes or, more specifically, of increases in prostaglandin synthesis in the muscles.

Adult↗
PubMed1999

Measurement of maximal oxygen uptake from two different laboratory protocols in runners and squash players.

PURPOSE: The aims of the study were to assess whether different test protocols used to elicit maximal oxygen uptake values (VO2max) attain similar results, whether different VO2max protocols were preferable for different athletic groups, and to assess whether the noninvasive criteria used to indicate the attainment of VO2max are achieved similarly in different VO2max testing protocols. METHODS: This study evaluated the attainment of either VO2max or peak VO2 (VO2peak) during two treadmill VO2max protocols: a progressive speed protocol (PSP) and a progressive incline protocol (PIP). Ten runners and 10 squash players were studied to assess whether achievement of VO2max criteria was either sport-specific or protocol-specific, or both. RESULTS: There were no significant differences in the VO2peak values reached in either PSP or PIP protocol (64.4 +/- 5.9 vs 66.5 +/- 6.0 mLO2 x kg(-1) x min(-1)). But HRmax (196 +/- 5 vs 189 +/- 5 beats x min(-1); PSP vs PIP; P < 0.01) and RER (1.14 +/- 0.05 vs 1.07 +/- 0.04; PSP vs PIP; P < 0.01) were significantly higher during the PSP test. Fifty percent of the subjects reached a plateau in either test, and of these subjects, 90% satisfied the three noninvasive criteria for VO2max in the PSP group, compared with 10% in the PIP group. CONCLUSIONS: The indirect criteria used to assess the attainment of VO2max may be limited, as the VO2peak values were higher in the PIP protocol compared with the PSP protocol, although not significantly different, whereas the HR and RER values were significantly lower in the PIP than PSP protocol. Furthermore, only 50% of subjects demonstrated the plateau phenomenon in oxygen uptake with either protocol. It may be concluded that the measured physiological variables coinciding with VO2peak may differ when different protocols are used to elicit VO2max.

Adult↗
PubMed1998

Prediction of maximal oxygen uptake from a 20-m shuttle run as measured directly in runners and squash players.

The aim of this study was to assess the validity of the multistage shuttle run test in predicting maximal oxygen uptake (VO2 max) in athletes trained in sports with different physical demands. Over a 14-day period, 10 male long-distance runners (continuous high-intensity exercise) and 10 male squash players (intermittent high-intensity exercise) performed, in random order, the multistage shuttle run test and a maximal treadmill protocol of increasing elevation which elicited VO2 max. Compared with direct measurement of VO2 max, the shuttle run test significantly underpredicted the VO2 max of the group of runners (n = 10; P < 0.01) and of the athletes as a whole (n = 20; P < 0.01). The correlation (r) between VO2 max determined by the shuttle run test and by the treadmill protocol was 0.61 (P < 0.05) for the squash players, 0.71 (P < 0.05) for the runners and 0.67 (P < 0.01) for the athletes as a whole. As the subjects represented athletes trained specifically in sports with different physical demands, this may explain why the correlations between the shuttle run test and direct measurement of VO2 max are less robust than those reported in previous studies. Furthermore, our results indicate that there are sport-specific differences when predicting VO2 max from the multistage shuttle run test.

Adult↗
PubMed1998

Prevalence of androgenic-anabolic steroid use in adolescents in two regions of South Africa.

OBJECTIVE: To determine the prevalence of androgenic-anabolic steroid (AAS) use among schoolchildren in two geographically separate regions of South Africa. DESIGN: Self-reported questionnaire. POPULATION: Standard 10 schoolchildren (16-18 years) were selected, 1,136 from region A and 1,411 from region B. RESULTS: The prevalence of AAS use in the overall population was 14.4/1,000. There were significant differences in prevalence of AAS use between the two regions (5.9/1,000 v. 22.7/1,000; P < 0.0005). There was significantly higher use in males (28.2/1,000) compared with females (0.7/1,000) (P < 0.005). Gymnasia were the most common source of AAS. Although there were regional differences in general knowledge about AAS, general knowledge scores were low across all the groups. Male sports participants who used AAS experienced significantly higher pressure to perform than their non-user counterparts in both regions. CONCLUSIONS: Regional differences in AAS use and general knowledge about AAS need to be considered before a meaningful programme can be implemented to reduce the use of AAS by South African schoolchildren.

Adolescent↗
PubMed1997

Physiological and subjective measures of workload when shovelling with a conventional and two-handled ('levered') shovel.

Previous studies have suggested that the two-handled (levered) shovel is advantageous over the conventional spade from a biomechanical point of view. The aim of this experiment was to determine whether less energy was consumed while shovelling a load of sand with this shovel compared to a conventional tool. Accordingly, an experiment was designed in which subjects (n = 10) shovelled 1815 kg sand under laboratory conditions using either a conventional or a levered shovel. Heart rate and oxygen consumption were measured continuously during the trial and subjective data on perceived exertion, general fatigue and body discomfort were recorded after the trial. Although total energy expenditure was similar under both conditions (120 +/- 20 and 125 +/- 25 kcal; conventional versus two-handled spade), average heart rate was 4% higher when the two-handled shovel was used (p < 0.05). In addition, the mass of sand per scoop was 4% less with the two-handled shovel (p < 0.05). In conclusion, subjects used similar energy expenditure to shovel 1815 kg sand with the conventional shovel and the two-handled tool despite lower mass of sand per scoop with the latter. This can be explained by the fact that the increased mass of the additional handle compensated for the lower mass of sand per scoop. The higher average heart rate while shovelling with the two-handled shovel can be explained by the more erect posture.

Adult↗
PubMed1997

The 'worn-out athlete': a clinical approach to chronic fatigue in athletes.

Chronic fatigue in the athletic population is a common but difficult diagnostic challenge for the sports physician. While a degree of fatigue may be normal for any athlete during periods of high-volume training, the clinician must be able to differentiate between this physiological fatigue and more prolonged, severe fatigue which may be due to a pathological condition. As chronic fatigue can be the presenting symptom of many curable and harmful diseases, medical conditions which cause chronic fatigue have to be excluded. The clinician must then be able to differentiate between chronic fatigue associated with training or chronic fatigue from other medical causes, and also between the chronic fatigue syndrome and the overtraining syndrome. Once the clinician has excluded all of the above medical conditions which cause chronic fatigue in athletes, a significant proportion of fatigued athletes remain without a diagnosis. Novel data indicate that skeletal muscle disorders may play a role in the development of symptoms experienced by the athlete with chronic fatigue. The histological findings from muscle biopsies of athletes suffering from the 'fatigued athlete myopathic syndrome' are presented. We have designed a clinical approach to the diagnosis and work-up of the athlete presenting with chronic fatigue. The strength of this approach is that it hinges on the participation of a multidisciplinary team in the diagnosis and management of the athlete with chronic fatigue. The athlete, coach, dietician, exercise physiologist and sport psychologist all play an important role in enabling the physician to make the correct diagnosis.

Chronic Disease↗
PubMed1996

Tests of running performance do not predict subsequent spontaneous running in rats.

Rats of similar mass and genetic stock have up to a 50-fold difference in spontaneous daily running distance. However, the reasons for this large variability in spontaneous running distance are not known. This study examined whether tests of running performance predict subsequent spontaneous running distance in rats housed in individual running wheel cages. Long-Evans rats (n = 56) were randomly assigned to either a sedentary control group (C) or a group housed in specially designed wheel cages in which they were able to exercise spontaneously (ES). They then underwent a high-intensity running test (MAX), during which oxygen consumption was measured at a submaximal (VO2 submax) and maximal workload (VO2 max). The rats' submaximal running endurance (END) and maximal sprinting speed (SPRINT) were also tested on the treadmill. After 8 weeks the average spontaneous running distance of ES was 29.7 +/- 3.7 km.wk-1 (mean +/- SE), but ranged from 1.4 to 71.1 km.wk-1. Tests of running performance and oxygen consumption were repeated in both groups, followed by in situ measurements of muscle contractile properties and of citrate synthase activity in the skeletal muscle. None of the measurements of running performance or oxygen consumption during the initial tests conducted at the start of the experiment was related to subsequent average spontaneous running distance. After 8 weeks, the mean peak force generated by the electrically stimulated gastrocnemius/plantaris muscles was greater in ES than in C (746 +/- 89 vs. 455 +/- 28 mg, p < 0.005), but this difference was not related to spontaneous running distance. Conversely, citrate synthase activity of the soleus muscle after training was related to average spontaneous running distance (r = 0.92, p < 0.0004). Average spontaneous running distance was also related to MAX (r = 0.65, p < 0.002), END (r = 0.59, p < 0.0009), and SPRINT (r = 0.61, p < 0.0005) and was inversely related to running intensity (r = -0.66, p < 0.002) after 8 weeks of training. It can be concluded from this study that 1) spontaneous running distance in rats cannot be predicted by pretraining tests of running performance. Hence, low levels of spontaneous running activity in some rats are not explained by skeletal muscular and cardiovascular factors thought to determine running capacity, and 2) posttraining tests of running performance were proportionally related to total spontaneous running distance and muscle oxidative enzyme changes but not to the in situ contractile properties of the muscles.

Animals↗
PubMed1996

A high prevalence of abnormal personality traits in chronic users of anabolic-androgenic steroids.

OBJECTIVE: (1) To assess the personality profiles of the anabolic androgenic steroid users (AAS) and (2) to determine whether valid premorbid personality traits could be obtained from cross sectional assessment using multisource data. METHODS: The first author became a participant-observer in a group of body builders. An experimental group of body builders who had been using AAS for no more than 18 months (n = 12) was identified. A group of control subjects, each of whom claimed that he did not, and never had, used AAS (n = 12) was also recruited during this period. Key informants played a crucial role in recruiting subjects representative of the AAS and body building communities. An interview schedule based on the Diagnostic and statistical manual of mental disorders (DSM3-R) personality disorder criteria was conducted with each subject. Additional data were obtained from an AAS using informant and significant others including family and friends. RESULTS: The user group was significantly heavier than the control group and showed abnormal personality traits, in contrast to the control group. Personality traits of AAS users before the onset of AAS use, assessed retrospectively, were not different from personality traits of control subjects. There were significant differences between the before and after personality traits in AAS user group. CONCLUSIONS: The results suggest (1) that AAS use is associated with significant disturbances in personality profile, and (2) that these personality disturbances are possibly the direct result of AAS use.

Adolescent↗
PubMed1996

Intra-operative pneumatic tourniquet--perceptions of use and complications in the orthopaedic community of South Africa.

OBJECTIVES: To assess views on use, maintenance and side-effects of the pneumatic tourniquet in the South African orthopaedic community. METHODS: A census-type questionnaire study was conducted of all 475 orthopaedic surgeons registered with the Orthopaedic Association of South Africa during 1993/94. The chi-square test was used to determine statistical significance between different groups of respondents. RESULTS: Seventy-seven per cent of the questionnaires were returned. Ninety-nine per cent of respondents used a pneumatic tourniquet. Eighty-four per cent believed that the tourniquet may damage underlying tissue both as a result of applied pressure effects and ischaemic consequences. Fifty-four per cent of respondents personally checked the calibration of the pneumatic tourniquet, although 76% of respondents believe that the apparatus needs to be checked at least once per month. More respondents who did not check the tourniquet apparatus than respondents who did check it believe that applied pressure does not cause tissue damage (P < 0.001), that the operating room technician or hospital engineer should be responsible for checking equipment (P < 0.001), and that equipment did not need to be checked more than once every 6 months (P < 0.001). CONCLUSIONS: Although most orthopaedic surgeons are aware of the pneumatic tourniquet's side-effects, a minority appear to be unaware of the hazards of excessive applied pressure alone or excessive applied pressure caused by use of faulty equipment. It needs to be emphasised to these surgeons that regular checking of the pneumatic tourniquet apparatus is necessary in order to prevent postoperative complications ascribed to use of the tourniquet.

Bandages↗
PubMed1995

The relationship between critical power and running performance.

Critical power is a theoretical concept that presumes there is a certain work-rate which may be maintained without exhaustion. The extent to which critical power predicts running performance over varying distances has not been determined, and so the aim of this study was to correlate measurements of critical power in the laboratory to running performances in the field at 40 m and 1, 10 and 21.1 km in a group of .17 male long-distance runners (mean +/- S.D. age = 31.7 +/- 7.3 years). Each subject ran to exhaustion on the treadmill in the laboratory at six different speeds, ranging from 17 to 25 km h-1. Least squares analyses were used to fit an exponential decay to the relationship between the running speed (y) versus time to exhaustion (x). Critical power was calculated as the running speed (y) coinciding with the asymptote or C parameter of the y = A.e(-Bx) + C relationship. The VO2 max was also measured in all subjects. For the data in the field, each subject was timed over 40 m and 1 km and participated in 10- and 21.1-km races. The mean critical power of the subjects in this study was 18.5 +/- 1.6 km h-1. The test-retest correlation coefficient for the determination of critical power was r = 0.99. The mean VO2 max, measured in a progressive exercise protocol starting at 13 km h-1 and increasing by 1 km h-1 every minute, was 59.2 +/- 4.6 ml O2 kg-1 min-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Running intensity as determined by heart rate is the same in fast and slow runners in both the 10- and 21-km races.

The aims of this study were to determine (1) whether running speed is directly proportional to heart rate (HR) during field testing and during 10- and 21-km races, and (2) whether running intensity, as estimated from HR measurements, differs in 10- and 21-km races and between slow and fast runners at those running distances. Male runners were divided into a fast (65-80 min for 21 km; n = 8) or slow (85-110 min for 21 km; n = 8) group. They then competed in 10- and 21-km races while wearing HR monitors. All subjects also ran in a field test in which HR was measured while they ran at predetermined speeds. The 10-km time was significantly less in the fast compared with the slow group (33:15 +/- 1:42 vs 40:07 +/- 3:01 min:s; mean +/- S.D.), as was 21-km time (74:19 +/- 4:30 vs 94:13 +/- 9:54 min:s) (P < 0.01). Despite the differences in running speed, the average running intensity (%HRmax) for the fast and slow groups in the 10-km race was 90 +/- 1 vs 89 +/- 3% and in the 21-km race 91 +/- 1 vs 89 +/- 2%, respectively. In addition, %HRmax was consistently lower in the field test at the comparative average running speeds sustained in the 10-km (P < 0.01) and 21-km (P < 0.001) races. Hence, factors in addition to work rate or running speed influence the HR response during competitive racing. This finding must be considered when running intensity for competitive events is prescribed on the basis of field testing performed under non-competitive conditions in fast and slow runners.

Adult↗
PubMed1995

Anabolic-androgenic steroid increases running endurance in rats.

The study was designed to determine whether treatment with an anabolic-androgenic steroid enhances running performance in rats by increasing their freely chosen training distance. Forty male Long-Evans rats were randomly divided into either a sedentary control group or an exercising group caged in specially designed running wheels in which the rats were able to run spontaneously. After 4 wk, both groups were further subdivided into two groups receiving either 0.5-mg Durabolin (nandrolone phenylpropionate) (im) or 0.5-mg saline, every second day. After 8 wk, running distance was similar in both exercising groups. Rats receiving the anabolic-androgenic steroid ran 41% longer during the test of submaximal running endurance compared to the trained rats receiving saline (P < 0.05). Submaximal running endurance was not increased in sedentary rats receiving the anabolic-androgenic steroid. After 4 wk of training, the maximal sprinting speed increased by 29% in trained rats. There was no further increase in maximal sprinting speed after an additional 4 wk of training and treatment with either anabolic-androgenic steroid or saline treatment. Therefore, rats that train spontaneously while being treated with an anabolic-androgenic steroid had increased submaximal running endurance compared with trained rats treated with saline, despite the similar voluntary training distance and skeletal muscle oxidative capacity between the two groups. The mechanism by which treatment with an anabolic-androgenic steroid, combined with training, enhances submaximal running performance could not be identified and needs to be addressed in future studies.

Anabolic Agents↗
PubMed1994

Relationship between energy expenditure and productivity of sugar cane cutters and stackers.

The main aim of this study was to measure the energy expenditure of sugar cane cutters and stackers during a normal working day and to relate this to their productivity (tonnes of cane cut or stacked per day). A secondary aim of the study was to relate the food and fluid ingestion of the workers during the day to energy expenditure, productivity and changes in body mass. Cutters (n = 12) and stackers (n = 12), who were randomly selected from all the workers (n = 50) on a Natal sugar estate in South Africa, wore heart rate monitors for the entire working day (7 h +/- 30 min). On a separate occasion, all subjects underwent treadmill exercise tests in which oxygen consumption (VO2) and heart rate (HR) were measured simultaneously. A VO2-HR regression equation was calculated for each subject. Based on this regression equation, energy expenditure (kJ) for the working day was calculated for each subject. There was no difference in the mean productivity of the cutters (9.0 +/- 0.7 tonnes) compared to the stackers (9.0 +/- 0.5 tonnes). Both groups expended a large and similar amount of energy during the working day (cutters = 11,695 +/- 1288 kJ; stackers 14,127 +/- 1710 kJ). They ingested similar amounts of energy while working (cutters = 5179 +/- 161 kJ; stackers = 5281 +/- 324 kJ). The best predictor of productivity was the length of the working day (r = 0.63), followed by the energy expended (r = 0.60). Despite the large amount of fluid ingested (up to 6.0 litres/day), some workers lost more than 3% of their body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Enhanced adipose tissue lipoprotein lipase activity in detrained rats: independent of changes in food intake.

Short-term detraining has been characterized by increased body mass and rapid body fat accretion. However, detraining has also been associated with increased food intake, especially in rats genetically predisposed to obesity. Thus, it has been difficult to separate refeeding effects from alterations resulting from the cessation of exercise training. In the present study, the in vitro activity of adipose tissue lipoprotein lipase (ATLPL) was measured in freely running wheel-trained rats and rats that had stopped training for 1, 2, or 3 days or 1 or 2 wk, respectively. Heparin-releasable ATLPL activity was measured at rest and after acute exhaustive exercise. Feeding efficiency (change in body mass/kJ ingested energy), fat pad mass, and adipocyte size were also measured. The rate of weight gain in 1- and 2-wk detrained rats was significantly higher than that of sedentary control or trained rats (P < 0.05). Feeding efficiency was also higher in 1-wk detrained rats than in all other groups (P < 0.005). However, food energy intake was not different between trained rats, 1- and 2-wk detrained rats, or sedentary control rats. ATLPL activity in all groups was highest after acute exhaustive exercise. ATLPL activity in 1-wk detrained rats was nearly threefold higher compared with that in trained rats (P < 0.005) and was not different from that of sedentary control rats. These results suggest that the cessation of exercise training causes an enhanced capacity for lipogenesis independent of changes in food energy intake or the acute effects of the last bout of exercise.

Adipocytes↗