SEARCH · PubMed Health

Results for “Weight Lifting”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed1977

Skeletal muscle fiber splitting induced by weight-lifting exercise in cats.

Adult skeletal muscle hypertrophy induced by exercise has been thought to be exclusively related to an increase in cross-section area of individual muscle fibers and not to an increase in the number of muscle fibers. Recent experiments using surgical intervention to cause muscle overload have induced an increase in fiber numbers; however, the muscle also exhibited pathological alterations. The purpose of this study was to determine if an exercise regimen also induced hyperplasia. Cats were trained to lift weights with their right forelimb to receive a food reward. After 19-46 weeks of training, the flexor carpi radialis muscle (FCR) was removed and prepared for histochemical examination. The total number of muscle fibers of the right exercised FCR increased significantly (19.3%) when compared with that of the unexercised left FCR (p less than 0.05). This increase was found to be due to muscle fiber splitting.

Adenosine Triphosphatases↗

PubMed1987

Kinematic form and scaling: further investigations on the visual perception of lifted weight.

Observers are able to judge accurately the weight lifted by another person when only the motions of reflective patches attached to the lifter's major limb joints and head can be seen (Runeson & Frykholm, 1981). What properties of these complex kinematic patterns allow judgments of weight to be made? The pattern of variation in velocity of the lifted object over position is explored as a source of information for weight: It is found to provide limited information. How are variations in kinematic patterns scaled to allow judgments of weight, a kinetic quantity? The possibility of a source of information for scaling in the kinematics is investigated. Judgments based only on patch-light displays are accurate to a degree that is improved by an extrinsic scaling basis. Finally, the sensitivity to scaling of alternative metrics used in judging is explored. Intrinsic metrics are discovered to be less sensitive to the absence of an extrinsic basis for scaling.

Concept Formation↗

PubMed1987

Increased HDL-cholesterol levels with a weight lifting program.

Weight training regimens are generally thought not to improve cardiovascular function or lipid parameters. To evaluate this further, we studied 25 men before and after supervised weight training three times each week for eight weeks. Mean plasma HDL-cholesterol level increased significantly with training, from 38.8 to 44.1 plasma HDL-cholesterol level increased significantly with training, from 38.8 to 44.1 mg/dl, while calculated LDL-cholesterol decreased from 132 to 121 mg/dl. Triglyceride values were unchanged. Percent fat decreased from 14% to 12.7% (P less than .05), and muscle mass increased from 32.4 kg before training to 37 kg after training (P less than .05). Maximal oxygen consumption (VO2max) increased significantly (from 45.2 to 49.2 ml/kg X min) during the eight-week period. LDL-cholesterol and triglycerides were negatively correlated with VO2max but changes in HDL-cholesterol were not accounted for by alterations in VO2max, muscle mass, or percent fat. This study suggests that weight training can be used to increase strength, alter body composition, improve plasma lipids, and enhance cardiovascular function.

Adolescent↗

PubMed1990

[Sport-specific injuries in weight lifting].

121 weight-lifters reported their past injuries due to their sport. 32% never had had any sports related medical problem. From the remaining 68%, 202 instances of injuries related to weight lifting were reported. They affected the knees (25%), scapular girdle (22%), back (21%), wrist (12%) and the elbows (6%). In about 10% of the known cases of knee injury, the rest period without any sports activity lasted more than 28 days. More often than not, it was due to degenerative processes of the joint. Sportsmen fear particularly shoulder injuries during the snatch movements. Accidents could be prevented to a large extent by relevant preventive actions such as warm-up exercises, a strict hygiene of the weights and devices and, most importantly, stable footwear.

Adult↗

PubMed1986

Hormone and metabolite response to weight-lifting training sessions.

Eleven weight-trained athletes (age X +/- SD = 33 +/- 5 yrs, weight = 72 +/- 10 kg) with a maximal performance in bench press at the beginning of the study (116 +/- 19 kg) were studied at rest, after a standardized submaximal training session, and after a maximal session once a month for 4 months to study the blood metabolites and hormonal changes during weight lifting. The submaximal load was six series of eight bench presses at 70% of maximal performance presses, and the maximal load was the maximal number of repetitions at the same work load. The levels of several metabolites (lactate, glycerol, triglycerides, beta-OH-butyrate) and hormones (norepinephrine and epinephrine) increased (P less than 0.05) after submaximal work and more after maximal work. Glucose, FFA, acetoacetate, insulin, testosterone, and cortisol did not change significantly or consistently. Lactate after maximal work was higher after the 4th training month (P less than 0.05). Other variables did not change much with training while the maximal number of repetitions in the last series increased slightly (P less than 0.05). In general, the changes observed were smaller than the ones reported for endurance or interval running, which use larger muscle groups. Nevertheless, weight lifting induced changes in blood metabolites which reflect a mobilization of both carbohydrates and lipids stores for energy.

Adult↗

PubMed1987

Plasma volume changes and cardiovascular responses associated with weight lifting.

Ten experienced weight lifters were studied to determine the influence of strenuous, free-weight, squat lift exercise on changes in plasma volume, mean arterial pressure, and the rate pressure product. After a 40-min postural adjustment prior to upright exercise, each subject completed eight sets of eight repetitions of the squat exercise at 55% of the one-repetition maximum. Electrocardiogram heart rate was monitored throughout the test, and blood pressure was determined at the completion of each exercise set. Arterialized capillary blood was drawn during sitting and standing pre-exercise and at the end of the second, fourth, sixth, and eighth sets for the measurement of hemoglobin, hematocrit, and plasma protein concentration, and after the last set for blood lactate. Five additional subjects participated in a postural control comparison. The results of the ANOVA showed a significant loss in plasma volume over the trials which was 2 1/2 times greater than for the control subjects (17.9 vs 7.7% loss) over the same period of time. Exercise rate pressure product increased by 2.85 times resting while only 1.1 times resting for the control subjects. An elevation in mean arterial pressure was found to be correlated to changes in plasma volume, r = -0.98. This study found that plasma volume is reduced while the rate pressure product is increased during the squat lift exercise.

Adult↗

PubMed1989

Relation of plasma volume change to intensity of weight lifting.

To determine the relation of plasma volume change to intensity of weight lifting, blood samples were obtained from 15 males [mean (+/- SD) age = 22.3 +/- 3.2 yr; height = 176.3 +/- 6.9 cm; weight = 73.0 +/- 11.7 kg] before and over a 60-min period following weight lifting at four different intensities [40, 50, 60, and 70% of one-repetition maximum (1-RM)]. Weight lifting consisted of completing three circuits of four exercises (bench press, bent-over row, arm curl, and parallel squat), with 10 repetitions of each exercise performed over a 30-s period followed by 30 s of rest. Mean (+/- SE) oxygen uptakes (VO2) during weight lifting at the four intensities were 1.31 +/- 0.04, 1.50 +/- 0.07, 1.72 +/- 0.07, and 1.86 +/- 0.08 1.min-1, or 33-47% of treadmill-determined VO2max, respectively. Mean (+/- SE) blood lactates were 6.5 +/- 0.5, 8.7 +/- 0.5, 9.4 +/- 0.6, and 12.0 +/- 0.6 mmol.1(-1), respectively. Mean (+/- SE) heart rates (HR) were 124 +/- 4, 134 +/- 4, 148 +/- 5, and 161 +/- 4 bpm, or 63-82% of treadmill-determined HRmax, respectively. Plasma volume decreased linearly in relation to intensity of weight lifting with mean responses of -7.7 +/- 0.8, -10.7 +/- 0.8, -12.1 +/- 0.9, and -13.9 +/- 0.8% at 40, 50, 60, and 70% of 1-RM, respectively. It was concluded that plasma volume decreases linearly in relation to intensity (%1-RM) of weight lifting and that the relation is similar to that reported for dynamic, low-resistance exercise such as cycling and running.

Adult↗

PubMed1990

Positive adaptations to weight-lifting training in the elderly.

Maximal weight-lifting performance, isometric strength, isokinetic torque, whole muscle and individual fiber cross-sectional areas, and muscle evoked contractile properties were assessed in 14 elderly males before and after 12 wk of weight-lifting training. Dynamic elbow flexion training of one arm resulted in a significant 48% mean increase in the maximal load that could be lifted once (1 RM) and a smaller improvement in isokinetic torque (8.8%) but no change in isometric strength. In the contralateral control arm, 1 RM and isokinetic torque increased by 12.7 and 6.5%, respectively, but isometric strength did not change. The interpolated twitch technique confirmed complete motor unit activation during a maximal isometric contraction of the elbow flexors before and after the training. Bilateral leg press training effected mean increases of 17 and 23% in isokinetic torque and dynamic lifting capacity, respectively. The mean maximal cross-sectional area of the elbow flexors (biceps brachii and brachialis) increased by 17.4% in the trained arm but did not change the control arm. The increase in the mean area of type II fibers in the biceps brachii muscle in the trained arm (30.2%) was greater than the corresponding change in the control arm (10.7%, P less than 0.05). The most significant change in the evoked contractile properties of the trained elbow flexors was the increase in twitch half-relaxation time. It is concluded that older individuals retain the potential for significant increases in strength performance and upper limb muscle hypertrophy in response to overload training.

Adaptation, Physiological↗

PubMed1989

Serum and urinary markers of skeletal muscle tissue damage after weight lifting exercise.

The purpose of this study was to determine whether high intensity weight lifting exercise produces elevations of urinary 3-methylhistidine (3-MH), serum creatine kinase activity (CK), and serum myoglobin concentration (MY), and whether trained weight lifters differed in such responses when compared to a group of untrained subjects. Ten experienced male weight lifters (EWL) and seven untrained male subjects (IWL) performed three sets of six weight lifting exercises at 70%-80% of 1 RM. All subjects consumed a meat-free diet. The 3-MH:creatinine (3-MH:CR) values decreased 24 h and 48 h following exercise (P less than 0.05). The 12-h and 24-h postexercise CK response and the 12-h postexercise MY response increased for both EWL and IWL (P less than 0.05). However, EWL had a lower 24-h postexercise CK response and lower 12-h and 24-h postexercise MY responses compared to IWL (P less than 0.05). Within 48 h following weight lifting exercise, skeletal muscle protein degradation (as assessed by 3-MH:CR values) decreased regardless of prior training experience whereas skeletal muscle tissue damage (as assessed by CK and MY responses) increased. However, prior weight lifting training appeared to diminish the extent of muscle tissue damage.

Adult↗

PubMed1991

Independent digit control: failure to partition perceived heaviness of weights lifted by digits of the human hand.

1. A weight-matching task was used to investigate the ability to estimate heaviness when weight lifting was isolated to the extrinsic flexor muscles (or portions thereof) that act on the digits of the hand. 2. Subjects matched a reference weight (200 g) lifted by a digit on the right with a variable weight lifted by the left thumb; a concurrent weight was simultaneously lifted by a digit on the right (reference) side. The reference and concurrent weights were lifted either by the same muscle (digital portions of flexor digitorum profundus), or anatomically separate but functionally related muscles (flexor digitorum profundus and flexor pollicis longus). Anaesthesia of the radial nerve and/or posturing of the hand was used to eliminate any small forces generated by co-contraction of the extensor muscles of the digits. 3. When the concurrent weight was equal to or greater than the reference weight, the perceived heaviness of the reference weight increased significantly from control trials (in which no concurrent weight was lifted). Although perceived heaviness of the reference weight increased progressively as the concurrent weight increased, reproducibility (expressed as the coefficient of variation) did not deteriorate when a weight was lifted concurrently. These findings were qualitatively similar when the reference and concurrent weights were lifted by two digital portions of flexor digitorum profundus or when the weights were lifted by flexion of the thumb and index finger. Also, anaesthesia of the digits which lifted the reference and concurrent weights did not alter the changes in perceived heaviness. 4. Perceived heaviness of the reference weight lifted by flexor digitorum profundus did not change when subjects lifted the concurrent weight with a remote muscle group (ankle dorsiflexors). 5. This study shows that signals of heaviness are systematically overestimated whenever more than one portion of the extrinsic muscles which flex the different digits are simultaneously active. Given that estimates of heaviness are biased by the central motor command, one explanation is that when the total motor drive increases, the central nervous system is unable to partition precisely the destination of motor commands to functionally related 'muscles'.

Electromyography↗

PubMed1991

A comparison between running and weight lifting on fasting plasma lipids of a well-conditioned hypercholesterolemic male.

The effect of weight lifting and running on the plasma lipid profiles of a physically fit 32-year-old hypercholesterolemic male were determined while he adhered to a controlled Phase III American Heart Association diet. The subject followed the same daily menu pattern for the entire test period. He completed four treatment phases: 6 weeks of detraining, 10 weeks of weight lifting, 10 weeks of running, and 10 weeks of weight lifting. The study was designed to closely compare two modes of exercise training for the same duration. A complete lipid profile was analyzed at baseline and every 5 weeks thereafter. Body weight and body fat remained constant throughout the study. Results revealed that running was the only effective treatment in raising high-density lipoprotein cholesterol (HDL-C). A return to weight lifting was associated with a 4 mg % decrease in HDL-C. The controlled low-fat, high carbohydrate, and low cholesterol diet effectively reduced total cholesterol, low-density, and high-density lipoprotein cholesterol in this hypercholesterolemic subject, while running increased HDL-C.

Adult↗

PubMed1986

Plasma volume change during heavy-resistance weight lifting.

Blood samples were obtained from six young men before, and over a 60-min period following a bout of heavy-resistance weight lifting to determine changes in plasma volume. Weight lifting consisted of three sets of four exercises (arm curl, bench press, bent-arm row, and squat) performed using 70% of one-repetition maximum for as many repetitions as possible. Plasma volume change was determined from haematocrit and haemoglobin concentration. During weight lifting, mean oxygen uptake and heart rate were 1.96 L X min-1 and 158 bt X min-1, respectively. Plasma volume was decreased -14.3% (p less than 0.05) immediately following exercise and -7.0% (p less than 0.05) at 15 min into recovery, but had returned to the resting level within 30 min. It was concluded that heavy-resistance weight lifting elicits a significant decrease in plasma volume, which is similar in magnitude to that observed during running and cycling at 80-95% of maximal oxygen uptake.

Adult↗

PubMed1992

Effects of carbohydrate loading and weight-lifting on muscle girth.

Bodybuilders have used different carbohydrate loading regimens in conjunction with resistance exercise prior to competition in the belief that this would result in increased muscle size. To investigate this possibility, muscle girth measurements were obtained from nine weight-trained males before and after a control (standard isocaloric diet) and an experimental trial (carbohydrate loading). The latter regimen consisted of 3 days of intense weight-lifting while the subjects ingested a diet of 10% carbohydrate (CHO), 57% fat (F), and 33% protein (P), followed by 3 days of light weight-lifting and a day of rest while ingesting a diet of 80% CHO, 5% F, and 15% P. The control trial consisted of an identical weight-lifting regimen while subjects ingested an isocaloric (45 kcal/kg BW/day) diet. Body weight and girths (forearm, upper arm, chest, thigh, waist, and calf) were obtained before and after each trial in a relaxed and flexed state. The results indicate that an exercise/carbohydrate loading regimen had no significant effect on muscle girth as compared to the control trial. It is concluded that CHO loading has no additional advantage to enhancing muscle girth in bodybuilders over weight-lifting alone.

Adipose Tissue↗

PubMed1985

The measurement of differential thresholds for lifted weights by microcomputer-controlled apparatus.

The measurement of differential thresholds (DLs) for lifted weights normally involves lengthy test sessions. This is due partly to the statistical techniques for measuring the threshold and partly to the methods adopted to present the stimuli. Attempts to speed up test procedures tend to produce unreliable DL estimates, or to measure the sense of force or effort rather than weight perception. To facilitate the measurement of DLs for lifted weights, an Apple microcomputer was programmed to generate Wetherill tracking procedures and was interfaced with two stimulus bearing turntables. Various lifting methods are easily implemented, and DLs are reliably and quickly measured. The adaptation of the apparatus for general use in investigating the haptic sense modality is discussed.

Computers↗

PubMed1991

Intracranial self-stimulation motivates weight-lifting exercise in rats.

The purpose of this study was to determine the feasibility of using a positive reinforcement protocol to motivate weight-lifting exercise in rats. Intracranial self-stimulation was used to induce weight-lifting exercise. Bipolar electrodes were implanted in the ventral tegmental area of rats, and the animals were trained to bar press on a continuous reinforcement schedule for electrical brain stimulation. Animals with response rates of 1,200-1,500 presses/h were then trained with a discriminative light stimulus to alternate between a normally positioned bar and an elevated bar that could be reached only by standing on the hindlimbs. The animals were fitted with a weighted jacket at a starting resistance of 5-10% of their body weight. Weight-training sessions were conducted 5 days/wk for 10 wk. Training consisted of 600 presses/session, alternating every 15 presses between the low and high bars. At the beginning of each subsequent week, the resistance was progressively increased, with some animals eventually training at resistances greater than 50% of their body weight. At the end of the training period, the rats were lifting over 550% of the starting weight. Gastrocnemius size and mean fiber diameter were increased in the weight-lifting animals. This model combines exercise with positive incentive and has the advantages of being relatively easy to implement and not producing any apparent physical or mental trauma in the animal.

Animals↗

PubMed1988

Skeletal muscle enlargement with weight-lifting exercise by rats.

A rat model of weight lifting that produces skeletal muscle enlargement utilizing regimens of resistance training similar to those employed in human training programs is described. The model consists of electrically stimulating the lower leg muscles to contract against a weighted pulley bar. Animals were subjected to training protocols employing low-frequency repetitions with high training loads within a training session. Initial maximum loads of between 200 and 800 g were progressively increased during the 16 wk of training. Work done at the end of the training period increased to an average value 66% higher than that performed at the start of training. The gastrocnemius wet weight and protein content increased (P less than 0.001) by 18 and 17%, respectively, in the stimulated loaded leg in all but one training protocol, a program in which rats were exercised more frequently. RNA content, but not concentration, was increased in the trained gastrocnemius muscle from each protocol, resulting in muscle enlargement. These data indicate that the basic model presented here provides a suitable vehicle for future studies into the biochemical events that may cause skeletal muscle enlargement during resistance training but, based on limited data, suggests that an increased frequency of training days may hinder muscle enlargement in this model.

Animals↗

PubMed1989

Effects of running or weight lifting on self-concept in clinically depressed women.

Forty clinically depressed women were randomized to a running, weight lifting, or delayed treatment condition. Self-concept was assessed at baseline, pre-, mid-, and posttreatment for all subjects and at 1, 7, and 12 months for exercise groups. Significant improvements in self-concept were found for exercise groups relative to control groups. No significant differences between exercise groups were found, and improvements were reasonably well-maintained over time. Differential changes on dimensions of self-concept were not demonstrated. These results suggest that both running and weight lifting exercise programs improve self-concept in clinically depressed women.

Adult↗

PubMed1985

Muscle fiber necrosis and regeneration induced by prolonged weight-lifting exercise in the cat.

For periods ranging from 26 to 87 weeks, the morphological characteristics of the flexor carpi radialis (FCR) muscle were examined in four cats trained to perform weight-lifting exercise. Four untrained, sex and weight-matched cats served as controls. The right FCR from each cat was surgically isolated, attached to a tension transducer, and set at its optimal length. The forelimb was perfused with 2% glutaraldehyde in 0.1 M cacodylate buffer. Small bundles of fibers were teased from their origin and insertion tendons and embedded in Epon. Spaced serial sections were used to examine the morphological features of the fibers for trained and control animals. Ultrastructural examination revealed muscle fiber degenerative changes, such as pyknotic nuclei, disruption of the sarcolemma, vacuolation, and disorganization of myofilaments. Such changes were observed at a higher frequency in trained muscle than in control muscle. Spaced serial sections of fiber bundles showed that the degree of degeneration varied along the length of the fiber. Fiber area measurements showed that trained muscle had both larger and smaller fibers than control samples. The very small fibers observed in the trained muscle were considered to be regenerating or "new" fibers since they had not undergone degenerative changes. "Satellite-like" cells were observed in trained muscle. Such cells resembled satellite cells but also contained developing myofilaments. Since evidence of degeneration-regeneration was observed in control samples, but at a lower frequency, it was postulated that weight-lifting exercise accelerates muscle fiber turnover in the cat FCR.

Animals↗