Increase In Muscular Strength Research Articles

Investigação dos efeitos da suplementação oral de arginina no aumento de força e massa muscular

INTRODUÇÃO: A administração oral de arginina tem sido relacionada com a melhora do desempenho físico por provável diminuição da fadiga muscular, decorrente do efeito vasodilatador do óxido nítrico sobre os músculos esqueléticos. OBJETIVO: Avaliar os efeitos da administração oral de L-arginina durante um programa de exercícios com pesos. MÉTODOS: 20 indivíduos do sexo masculino foram submetidos a oito semanas de treinamento com pesos (três vezes por semana), divididos aleatoriamente em dois grupos: ARG e CON. O grupo ARG fez uso de três gramas de L-arginina + vitamina C, durante as oito semanas e o grupo CON utilizou apenas vitamina C (grupo controle). RESULTADOS: Após oito semanas de treinamento, o grupo ARG apresentou valores de peso corporal e massa magra significativamente maiores (p < 0,05), percentual de gordura corporal significativamente menor (p < 0,05) e força de membros inferiores significantemente maior (p < 0,05), enquanto o grupo CON não mostrou diferenças significativas, para o mesmo período. CONCLUSÃO: A administração oral de arginina associada a um programa de treinamento com pesos potencializou os estímulos do exercício ao nível da musculatura esquelética, proporcionando o aumento de força e de massa muscular.

SIX MONTHS OF SUPERVISED HIGH-INTENSITY LOW-VOLUME RESISTANCE TRAINING IMPROVES STRENGTH INDEPENDENT OF CHANGES IN MUSCLE MASS IN YOUNG OVERWEIGHT MEN

To determine the effects of a 6-month supervised low-volume resistance training (RT) program (1 set, 85-90%, one repetition maximum, 1RM, 3 d x wk(-1)) on muscular strength (1RM) and skeletal muscle mass (SMM) in previously sedentary, overweight men on an ad libitum diet. Nineteen men were randomly assigned to a control (CON, n = 8) or RT (n = 11) group. The exercise protocol consisted of 5 upper- and 4 lower-body exercises using weight machines. CON maintained their sedentary lifestyle. One RM for upper body (chest press [CP] + lat pull-down [LPD]) and lower body (leg press [LP]) and SMM were assessed at baseline, and at 3 and 6 months. Adherence was 96 +/- 2% with an average time to complete each exercise session of 15 +/- 2 minutes. Volume completed per exercise session significantly increased from baseline (2,812 +/- 670 kg) to 6 months (6,411 +/- 2,128 kg). There was a group by time interaction in 1RM for CP, LPD, and LP. Upper-body strength increased significantly (p < 0.001) (31.3 +/- 9.3%) from baseline to 3 months and from 3 to 6 months (17.9 +/- 8.7%). Lower-body strength also increased significantly from baseline to 3 months (17.8 +/- 16.6%) and from 3 to 6 months (32.0 +/- 33.7%). No changes in upper- or lower-body strength occurred in the CON group. There was no group by time interaction for SMM (CON, 34.5 +/- 2.9 kg vs. RT, 34.2 +/- 2.9 kg; p > 0.05) or for energy intake (p > 0.05). In conclusion, a single set resistance training program at 85% of 1RM, 3 d x wk(-1) resulted in continued increases in muscular strength and a very high adherence rate over a 6-month period in sedentary, overweight men independent of significant changes in SMM. This training protocol may increase adherence and produce long-term increases in muscular fitness as part of an adult fitness program.

Concentric and eccentric isokinetic resistance training similarly increases muscular strength, fat-free soft tissue mass, and specific bone mineral measurements in young women

Women participated in 5 months of unilateral concentric (n = 37) or eccentric (n = 33) isokinetic resistance training of the legs and arms. Limb muscular strength increased as did total body, leg, and arm fat-free soft tissue mass, total body BMC, hip BMD, and forearm BMC and BMD. Isokinetic training benefits bone mineral acquisition. Isokinetic resistance training (IRT) is osteogenic; however, it is not known if concentric or eccentric modalities of IRT produce differential effects on bone. We tested our hypothesis that high-load eccentric versus concentric mode of IRT would produce greater increases in muscular strength, fat-free soft tissue mass (FFSTM), bone mineral density (BMD) and content (BMC) in trained legs and arms. Participants were randomized to 5 months of concentric (n = 37) or eccentric (n = 33) training. The non-dominant leg and arm were used during training; dominant limbs served as controls. Muscular strength was measured with an isokinetic dynamometer; body composition was measured by dual-energy X-ray absorptiometry. Muscular strength of the concentrically and eccentrically trained leg (18.6%; 28.9%) and arm (12.5%; 24.6%) significantly increased with training. Gains in total body (TB) BMC (p < 0.05) and, in the trained limbs, total proximal femur BMD (p < 0.05) and total forearm BMD (p < 0.05) and BMC (p < 0.05) occurred in both groups. FFSTM increased for the TB and trained leg and arm (all p < 0.001) in both modes. Regardless of the mode, high-intensity, slow-velocity IRT increases muscular strength and FFSTM of trained limbs and imparts benefits to TB BMC and site-specific BMD and BMC in young women.

The Adaptations to Strength Training

High-resistance strength training (HRST) is one of the most widely practiced forms of physical activity, which is used to enhance athletic performance, augment musculo-skeletal health and alter body aesthetics. Chronic exposure to this type of activity produces marked increases in muscular strength, which are attributed to a range of neurological and morphological adaptations. This review assesses the evidence for these adaptations, their interplay and contribution to enhanced strength and the methodologies employed. The primary morphological adaptations involve an increase in the cross-sectional area of the whole muscle and individual muscle fibres, which is due to an increase in myofibrillar size and number. Satellite cells are activated in the very early stages of training; their proliferation and later fusion with existing fibres appears to be intimately involved in the hypertrophy response. Other possible morphological adaptations include hyperplasia, changes in fibre type, muscle architecture, myofilament density and the structure of connective tissue and tendons. Indirect evidence for neurological adaptations, which encompasses learning and coordination, comes from the specificity of the training adaptation, transfer of unilateral training to the contralateral limb and imagined contractions. The apparent rise in whole-muscle specific tension has been primarily used as evidence for neurological adaptations; however, morphological factors (e.g. preferential hypertrophy of type 2 fibres, increased angle of fibre pennation, increase in radiological density) are also likely to contribute to this phenomenon. Changes in inter-muscular coordination appear critical. Adaptations in agonist muscle activation, as assessed by electromyography, tetanic stimulation and the twitch interpolation technique, suggest small, but significant increases. Enhanced firing frequency and spinal reflexes most likely explain this improvement, although there is contrary evidence suggesting no change in cortical or corticospinal excitability. The gains in strength with HRST are undoubtedly due to a wide combination of neurological and morphological factors. Whilst the neurological factors may make their greatest contribution during the early stages of a training programme, hypertrophic processes also commence at the onset of training.

Efeitos do treinamento de resistência na força muscular e níveis de fadiga em pacientes com câncer de mama

Os efeitos de programas generalizados de atividade física no combate ao câncer e aos efeitos colaterais de seu tratamento têm sido amplamente relatados na literatura. O objetivo do presente estudo foi o de examinar os efeitos de um programa de prescrição de exercício físico individualizado, com ênfase no treinamento resistido, na força muscular e nos níveis de fadiga em pacientes portadoras de câncer de mama em tratamento. Vinte mulheres foram divididas aleatoriamente em dois grupos, sendo um experimental (57,5 ± 23,0 anos) e um controle (56,6 ± 16,0 anos). O grupo experimental exercitou-se, após a cirurgia, durante 60 minutos, de forma moderada, duas vezes por semana, durante 21 semanas. A força muscular total foi avaliada antes e após o tratamento e os níveis de fadiga foram avaliados em três momentos durante o treinamento. Foram encontradas diferenças significativas na força muscular total entre os grupos após o treinamento (p = 0,025). Os níveis de fadiga diminuíram significativamente entre os grupos após a primeira (p = 0,001) e a segunda (p = 0,005) intervenção e ao final do tratamento (p = 0,001). Os resultados deste estudo sugerem que os exercícios resistidos devem ser incluídos na prescrição de exercícios no combate da fadiga e na melhoria da força muscular em mulheres com câncer de mama, submetidas a tratamento.

Neural Adaptations to Resistive Exercise

It is generally accepted that neural factors play an important role in muscle strength gains. This article reviews the neural adaptations in strength, with the goal of laying the foundations for practical applications in sports medicine and rehabilitation. An increase in muscular strength without noticeable hypertrophy is the first line of evidence for neural involvement in acquisition of muscular strength. The use of surface electromyographic (SEMG) techniques reveal that strength gains in the early phase of a training regimen are associated with an increase in the amplitude of SEMG activity. This has been interpreted as an increase in neural drive, which denotes the magnitude of efferent neural output from the CNS to active muscle fibres. However, SEMG activity is a global measure of muscle activity. Underlying alterations in SEMG activity are changes in motor unit firing patterns as measured by indwelling (wire or needle) electrodes. Some studies have reported a transient increase in motor unit firing rate. Training-related increases in the rate of tension development have also been linked with an increased probability of doublet firing in individual motor units. A doublet is a very short interspike interval in a motor unit train, and usually occurs at the onset of a muscular contraction. Motor unit synchronisation is another possible mechanism for increases in muscle strength, but has yet to be definitely demonstrated. There are several lines of evidence for central control of training-related adaptation to resistive exercise. Mental practice using imagined contractions has been shown to increase the excitability of the cortical areas involved in movement and motion planning. However, training using imagined contractions is unlikely to be as effective as physical training, and it may be more applicable to rehabilitation. Retention of strength gains after dissipation of physiological effects demonstrates a strong practice effect. Bilateral contractions are associated with lower SEMG and strength compared with unilateral contractions of the same muscle group. SEMG magnitude is lower for eccentric contractions than for concentric contractions. However, resistive training can reverse these trends. The last line of evidence presented involves the notion that unilateral resistive exercise of a specific limb will also result in training effects in the unexercised contralateral limb (cross-transfer or cross-education). Peripheral involvement in training-related strength increases is much more uncertain. Changes in the sensory receptors (i.e. Golgi tendon organs) may lead to disinhibition and an increased expression of muscular force. Agonist muscle activity results in limb movement in the desired direction, while antagonist activity opposes that motion. Both decreases and increases in co-activation of the antagonist have been demonstrated. A reduction in antagonist co-activation would allow increased expression of agonist muscle force, while an increase in antagonist co-activation is important for maintaining the integrity of the joint. Thus far, it is not clear what the CNS will optimise: force production or joint integrity. The following recommendations are made by the authors based on the existing literature. Motor learning theory and imagined contractions should be incorporated into strength-training practice. Static contractions at greater muscle lengths will transfer across more joint angles. Submaximal eccentric contractions should be used when there are issues of muscle pain, detraining or limb immobilisation. The reversal of antagonists (antagonist-to-agonist) proprioceptive neuromuscular facilitation contraction pattern would be useful to increase the rate of tension development in older adults, thus serving as an important prophylactic in preventing falls. When evaluating the neural changes induced by strength training using EMG recording, antagonist EMG activity should always be measured and evaluated.

Effects of training and detraining on the static and dynamic balance in elderly fallers and non-fallers: A pilot study

Purpose. The aim of this study was to evaluate the effects of training based on static and dynamic balance in single and dual task conditions in order to analyse the effects of detraining on static and dynamic balance in healthy elderly fallers and non-fallers.Method. A group of 16 subjects were trained: eight fallers aged 71.1 ± 5.0 years and eight non-fallers aged 68.4 ± 4.5 years. The subjects were evaluated 3 months before the training period, 2 days before the training period, 2 days after the end of the training period and 3 months after the training period. All subjects performed a unipedal test with eyes open and eyes closed. Gait parameters were analysed under single-task and dual motor-task conditions.Results. This study demonstrated a loss of physical capacities over 3 months for stride time, single support time for fallers in both conditions. Physical training significantly improves static and dynamic balance under single and dual task conditions. Lastly, after 3 months of detraining, a loss of the physical training effects were measured for fallers and non-fallers on the different walking parameters in the two conditions and on the unipedal tests.Conclusions. The absence of stimulation before the trained period shows a negative effect of ageing on walking and falls whereas training permits an improvement in static balance and the pattern of walking under single and dual task conditions, which could be due to an increase in muscular strength and a better division of attention. On the other hand, 3 months of detraining inhibited the effects of training, which showed the speed of the decline caused by ‘natural’ ageing.

High‐intensity resistance and cardiovascular training improve physical capacity in cancer patients undergoing chemotherapy

The purpose of the study was to examine the effects of a supervised high- and low-intensity structured training program in cancer patients concurrently undergoing chemotherapy. Seventy patients, in different stages of the disease and with different diagnoses (48 females, 22 males), between 18 and 65 years of age (mean age 42.8) participated in a 9-h weekly training program over 6 weeks. The intervention involved physical exercise, relaxation, massage, and body-awareness training. Physical capacity (one-repetition maximum tests (1RM), VO2max) and body composition (weight, skin-fold) were compared before and after the exercise intervention. The average increase in muscular strength was 41.3% (P<0.001) and 14.5% in aerobic fitness (pre: 2.27+/-0.597 L/min, post: 2.56+/-0.644 L/min, (P<0.001). The exercise intervention significantly increased the weight of the subjects by 1% (pre: 72.62+/-13.42 kg, post: 73.25+/-13.44 kg, P=0.016). There was a significant decrease in skin-fold measurements by 3% (P=0.031). The exercise intervention was well tolerated, provided that daily screening criteria were adhered to. The effects of resistance and cardiovascular training observed in this short-term study support the theory that exercise is a beneficial intervention strategy for increasing muscle strength and aerobic fitness during antineoplastic chemotherapy. This type of exercise program can be an important component of complementary treatment for cancer patients undergoing chemotherapy.

Aging, Resistance Training, and Motor Unit Discharge Behavior

Researchers have alluded the existence of "neural factors" in the expression and development of muscular strength. Candidate neural factors including motor unit recruitment, rate coding, double firing, and motor unit synchronization are discussed in this review. Aging is generally accompanied by lower motor unit discharge rates. However, both young and older adults exhibit rapid changes in muscular strength with repeated strength testing. These strength changes occur with concomitant albeit transient increase in motor unit discharge rate. These and other neural factors may contribute to the initial increase in muscular strength observed during the early phases of resistance exercise training.

Effect Of 6 Months Of Supervised Resistance Training In Overweight Young Men

The American College of Sports Medicine recommends resistance training (RT) as an integral part of an adult fitness program. RT should be of sufficient intensity to enhance muscular strength and endurance and to maintain or increase both fat-free mass (FFM) and physical function. One set of 8–10 exercises, 8–12 repetitions that condition the major muscle groups, 2–3 d/wk is recommended. However, other fitness experts have suggested that RT of at least 1 set to failure or multiple (3–6) sets are necessary to improve muscular fitness. While this strategy may potentially result in larger increases in muscular fitness than single set programs, adherence to this regime by untrained sedentary individuals is likely to be low, thus decreasing the programs long-term effectiveness. PURPOSE To determine the effect of a 6 month supervised RT program (1 set, 3–6 repetitions maximum (RM), 3 d.wk-1) on muscular strength (1 RM) and FFM (DEXA) in sedentary, overweight (mean ± SD) (BMI = 28.3 ± 2.3kgċm−2) young (age = 20.7 ± 2 yrs) men on a ad libitum diet. METHODS Nineteen men were randomly assigned to control (n = 8) or RT groups (n = 11). The exercise protocol consisted of 5 upper and 4 lower body exercises using weight machines. Controls maintained their sedentary lifestyle. One-RM for upper (chest press + lat pull) and lower (leg press) body and FFM were assessed at baseline, 3 and 6 months. RESULTS Adherence was 96 ± 2% with an average time to complete each exercise session of 15 ± 2 min. Upper body strength increased significantly (p <0.001) (31.3 ± 9.3%) from baseline to 3 months and from 3 to 6 months (17.9 ± 8.7%). Lower body strength also increased significantly from baseline to 3 months (17.8 ± 16.6%) and from 3 to 6 months (32.0 ± 33.7%). No changes in upper or lower body strength were noted in the control group. FFM was unchanged in both groups. CONCLUSION A single set RT program using 3–6 RM, 3 d.wk−1 resulted in continued increases in muscular strength and a very high adherence rate over a 6 month period in sedentary, overweight, young men independent of significant changes in FFM. This realistic training protocol may increase adherence and produce meaningful increases in muscular fitness as part of an adult fitness program. Supported by NIH Grant RO3 DK49181

Effect Of 6 Months Of Supervised Resistance Training In Overweight Young Men

The American College of Sports Medicine recommends resistance training (RT) as an integral part of an adult fitness program. RT should be of sufficient intensity to enhance muscular strength and endurance and to maintain or increase both fat-free mass (FFM) and physical function. One set of 8–10 exercises, 8–12 repetitions that condition the major muscle groups, 2–3 d/wk is recommended. However, other fitness experts have suggested that RT of at least 1 set to failure or multiple (3–6) sets are necessary to improve muscular fitness. While this strategy may potentially result in larger increases in muscular fitness than single set programs, adherence to this regime by untrained sedentary individuals is likely to be low, thus decreasing the programs long-term effectiveness. PURPOSE To determine the effect of a 6 month supervised RT program (1 set, 3–6 repetitions maximum (RM), 3 d.wk-1) on muscular strength (1 RM) and FFM (DEXA) in sedentary, overweight (mean ± SD) (BMI = 28.3 ± 2.3kgċm−2) young (age = 20.7 ± 2 yrs) men on a ad libitum diet. METHODS Nineteen men were randomly assigned to control (n = 8) or RT groups (n = 11). The exercise protocol consisted of 5 upper and 4 lower body exercises using weight machines. Controls maintained their sedentary lifestyle. One-RM for upper (chest press + lat pull) and lower (leg press) body and FFM were assessed at baseline, 3 and 6 months. RESULTS Adherence was 96 ± 2% with an average time to complete each exercise session of 15 ± 2 min. Upper body strength increased significantly (p <0.001) (31.3 ± 9.3%) from baseline to 3 months and from 3 to 6 months (17.9 ± 8.7%). Lower body strength also increased significantly from baseline to 3 months (17.8 ± 16.6%) and from 3 to 6 months (32.0 ± 33.7%). No changes in upper or lower body strength were noted in the control group. FFM was unchanged in both groups. CONCLUSION A single set RT program using 3–6 RM, 3 d.wk−1 resulted in continued increases in muscular strength and a very high adherence rate over a 6 month period in sedentary, overweight, young men independent of significant changes in FFM. This realistic training protocol may increase adherence and produce meaningful increases in muscular fitness as part of an adult fitness program. Supported by NIH Grant RO3 DK49181

What phenomena do occur in blood flow-restricted muscle?

Oxygen is an essential molecule for all cellular activities including growth. Either excessive or deficient oxygen supply to cells induces the various responses of the cells. In the field of pathophysiology, effects of blood flow restriction on various organs have been studied for the past ∼130 years. Subsequently, the roles of oxygen at subcellular level have been studied in vitro. Although a number of studies show that a low-intensity exercise (20∼50% of one repetition maximum) with a moderate tourniquet restriction of blood flow results in increases in muscular strength and size, the mechanisms for this muscular adaptation remain unclear. In particular, it is uncertain whether the low-intensity exercise with blood flow restriction using a tourniquet causes the hypoxia or hyperoxia in the muscle, and then what signals leading to muscular hypertrophy are activated inside and/ or outside the cells. Also, it is not well understood what side effects occur in addition to conferring the benefits of strength gains. The review summarizes recent studies on the muscular adaptations to oxygen environment and discusses the mechanisms that may be involved in the resistance exercise with restricted blood flow.

Effects of the Curves® Fitness Program on Muscular Strength, Muscular Endurance, and Maximal Aerobic Capacity

0533 PURPOSE: To examine the effects of the Curves fitness and diet program on muscular strength, muscular endurance, and maximal aerobic capacity. METHODS: 123 sedentary women (38.7 ± 8 yr; 93.2 ± 19 kg; 44.8 ± 4.8% body fat) participated in a 14- wk exercise and diet program. Subjects were randomly assigned to an exercise and no diet group (END); an exercise and high calorie mixed diet (2,600 kcals/d for 2 wks at 55% C, 15% P, 30% F; 8 wks at 40% C, 30% P, 30% F; 4 wks at 55% C, 15% P, 30% F) group (HCD); or, a low calorie high carbohydrate (HCHO), high protein (HP), or very high protein (VHP) diet group. Subjects consumed 1,200 kcal/d for 2-wks and 1,600 kcal/d for 8 wks. Subjects then ingested 2,600 kcal/d and 1,200 kcal/d diet at 3/2, 3/2, 5/2, & 10/2 day intervals in an attempt to maintain weight loss. Diets were standardized with 30% dietary fat with carbohydrate intake ranging from 40–55% on the HCD and HCO diets and protein intake ranging from 50–63% on the HP and VHP diets. Subjects participated in a supervised 30-min resistance training circuit program combined with calisthenic exercises 3-d per week. At 0, 10, and 14 weeks, subjects performed 1RM bench press and leg press, 80% of 1RM maximal repetition tests on the bench press and leg press, and a maximal cardiopulmonary exercise test. Repeated measures ANOVA results are presented as means ± SD from baseline. RESULTS: Training significantly increased bench press 1RM (2.37 ± 3.8 kg, p<0.006; 0.04 ± 0.04 kg/kg, p<0.001) and leg press 1RM (15.5 ± 38 kg, p<0.002; 0.27 ± 0.39 kg/kg, p<0.001) [10–15% gain in strength]. Bench press lifting volume (80% weight × repetitions) was unchanged (9.1 ± 126 kg, p = 0.20; 0.3 ± 1.4 kg/kg, p = 0.60). However, significant interactions (p<0.05) were observed indicating the END group experienced greater gains in bench press lifting volume. Leg press lifting volume significantly increased in all groups (325 ± 1,521 kg, p = 0.03; 4.1 ± 14 kg/kg, p = 0.006) with no significant differences among groups. Relative maximal oxygen uptake was significantly increased in all groups by about 7% (1.6 ± 3.5 ml/kg/min, p<0.002) primarily due to a significant weight loss. Resting heart (−4.2 ± 14.0 bpm, p<0.01), systolic blood pressure (−3.2 ± 13 mmHg, p<0.001), and diastolic blood pressure (−2.1 ± 10 mmHg, p<0.03) decreased. CONCLUSIONS: The Curves fitness program promotes increases in muscular strength, muscular endurance, and maximal aerobic capacity while decreasing resting heart rate and blood pressure. These findings indicate that this program appears to be an effective and appropriate level exercise program for this population.

Strength and Body Composition

0394 When designing optimal strength training programmes there are contrasting and conflicting recommendations regarding the number of weight-lifting sets required to elicit an increase in muscular strength. The prevalent recommendation is to perform multiple sets (at least three) in order to achieve maximal strength gains. The main advocates of multiple set training programmes propose that multiple sets are superior for achieving optimal physiological adaptation, and that single sets are most appropriate for untrained subjects. PURPOSE The purpose of this study was to determine the effects of increasing the volume of weight-training from one to three sets on muscular strength performances and body composition characteristics in a group of male recreational weight-trainers. METHODS Sixteen male weight-trainers volunteered to act as subjects and were random1y assigned to one of two training groups. Supervised weight-training targeting the upper body was conducted three times per week for eight weeks using one set (n = 8) or three sets (n = 8) of six repetitions to fatigue of variable resistance training exercises. Subjects were measured before and after the training intervention for adiposity (sum of seven skinfold thicknesses (mm)) and strength performance (N) using the one repetition maximum method on the bench-press, biceps curl and shoulder press. RESULTS Both training groups improved significantly in terms of muscular strength (P < 0.05) with no differences being observed between the one and three set group after the training intervention (P > 0.05). Significant decreases were also observed for adiposity in the one set group (P < 0.05). CONCLUSION In recreational weight-trainers over an eight-week period, one set of high intensity resistance training was as effective as three high intensity sets for increasing the strength of muscle groups in the upper body. The one set protocol also produced significantly greater decreases in adiposity. The implications of these findings are extremely attractive for both the sports and health orientated members of society.

No Effect of Resistance Training on Autonomic Cardiovascular Control

2399 Resistance exercise with either a small or large muscle mass causes transient doubling or tripling of arterial pressures that may severely challenge autonomic cardiac and baroreflex regulation. Potential chronic adaptations may be linked to resistance training mode, but studies describing autonomic cardiovascular adaptations to different resistance training regimens do not exist. PURPOSE: To evaluate the influence of high- and moderate-intensity resistance training on autonomic cardiovascular regulatory mechanisms. METHODS: Thirty two subjects (age 22 ± 0.6 yr) were assigned to one of three groups: resistance training for strength (RS, n = 12), resistance training for strength and endurance (RE, n = 10), or no exercise control (CON, n = 10). Subjects trained each major muscle group using 7 isotonic weight training machines 3 d/wk for 8 wk with 3 sets of 10 repetitions and 2 min rest periods (RS) or 3 sets of 15 repetitions with 30 s rest periods (RE). Resistance was progressively increased when possible. Before and after training, ECG, finger photoplethysmographic arterial pressures, and muscle sympathetic nerve activity (MSNA) were recorded with subjects supine and breathing at a set rate (0.25 Hz). Data were analyzed in both time and frequency domains. Arterial baroreflex sensitivity was assessed from cross-spectral transfer function analysis between systolic pressures and R-R intervals. RESULTS: Whole body strength increased by 22% (RS;P = 0.01) and by 21% (RE;P = 0.01). Aerobic capacity increased from 3.3 ± 0.8 to 3.7 ± 0.79 l/min (RE;P = 0.01). Muscular strength and aerobic capacity did not change for CON (P > 0.05). Heart rate and arterial pressure variability, MSNA, and arterial baroreflex sensitivity were unaffected by RS and RE. CONCLUSION: Despite significant increases in muscular strength (RS and RE) and aerobic capacity (RE), resistance training does not affect autonomic cardiovascular regulation. Supported by American Heart Association Grant 0030203N

Cooperative Effects of Exercise and Occlusive Stimuli on Muscular Function in Low-Intensity Resistance Exercise with Moderate Vascular Occlusion

To obtain insight into the relative contributions of exercise and occlusive stimuli to these muscular adaptations, the present study investigated the short- and long-term effects of varied combinations of low-intensity exercise and vascular occlusion. The subjects were separated into 3 groups (n = 6 for each group): low-intensity with vascular occlusion (LIO), low-intensity without vascular occlusion (LI), and vascular occlusion without exercise (VO). LIO and LI groups performed bilateral knee extension exercises in seated positions with an isotonic extension machine. In the LIO group, both sides of the thigh were pressure-occluded at the proximal end by means of a tourniquet during the entire session of exercise (approximately 10 min), whereas only the occlusion with the same pressure and duration was given in the VO group. The mean occlusion pressure was 218 +/- 8.1 mmHg (mean +/- SE). The exercise session consisted of five sets of exercise at an intensity of 10-20% 1RM and was performed twice a week for 8 wk. After the period of exercise training, isometric and isokinetic strengths at all velocities examined increased significantly in the LIO group (p < 0.05), whereas no significant change in strength was seen in the LI and VO groups. The increase in muscular strength in LIO was associated with a significant increase in the cross-sectional area of knee extensor muscles by 10.3 +/- 1.6%. The plasma growth hormone concentration measured 15 min after the session of exercise showed a marked increase only in LIO. The results showed that the low-intensity exercise and occlusive stimuli have cooperative effects in the long-term adaptation of muscle and an acute response to growth hormone.

The effects of four weeks of ribose supplementation on body composition and exercise performance in healthy, young, male recreational bodybuilders: a double-blind, placebo-controlled trial

Background: Ribose is a pentose sugar that is present in ribonucleic acids, riboflavin, nucleotides, and adenosine triphosphate. Whether exogenous ribose administration affects skeletal muscle concentrations of total adenine nucleotides is unknown. Whether supplementation with ribose positively affects body composition or exercise performance in recreational bodybuilders also is unknown. Objective: The purpose of this double-blind, placebo-controlled trial was to determine the effects of 4 weeks of ribose supplementation on body composition and exercise performance in healthy, young, male recreational bodybuilders. Methods: Healthy, male recreational bodybuilders aged 18 to 35 years were recruited and randomized to a ribose-supplemented group (10 g/d in powder formulation) or a placebo group (dextrose). Each subject participated in a heavy-resistance training program designed to increase skeletal muscle mass. Body composition (ie, body weight, body fat, lean body mass, fat mass, and bone mineral content) was assessed using dual-energy x-ray absorptiometry analysis. Muscular strength (as measured by a 1-repetition maximum-strength [1-RM] bench press) and total work performed (as measured by total repetitions for 10 sets of bench presses before muscular failure; 1-minute resting interval between sets) to muscular failure at a submaximal load (100% of pretest body weight) were ascertained. In addition, 24-hour dietary recalls were obtained before and after the study. Results: Twenty men (mean age ± SE, 23.9 ± 1.4 years) were enrolled; 19 subjects completed 24-hour dietary recalls and exercise performance testing; 12 subjects completed the study (24-hour dietary recalls, exercise performance, and body composition). No baseline differences were found between the 2 groups for any of the measured parameters. The ribose-supplemented group experienced a significant pretreatment-to-posttreatment increase in the total work performed, whereas the placebo group did not change significantly (24.5 ± 7.6 to 29.3 ± 7.5 repetitions; 19.6% ribose [ P = 0.028] vs 34.1 ± 8.6 to 38.2 ± 8.0 repetitions, 12.0% placebo). In addition, the ribose-supplemented group experienced a significant increase in 1-RM bench press strength, whereas the placebo group did not change significantly (114.1 ± 13.6 to 117.7 ± 14.0 kg, 3.2% ribose [ P = 0.008] vs 129.6 ± 14.2 to 131.8 ± 14.5 kg, 1.7% placebo). No pretreatment-to-posttreatment within-group or between-group differences were found for any of the measures of body composition or the 24-hour dietary data. Conclusion: The results of this study indicate that supplementation with ribose 10 g/d for 4 weeks resulted in significant increases in muscular strength and total work performed in recreational bodybuilders in this study, although no significant changes in body composition or 24-hour dietary data were found.

Effects of continuous and pulsed short-wave diathermy in low back pain

The purpose of this study was to investigate the effects of pulsed short-wave diathermy (PSWD) in patients with low back pain (LBP). Sixty patients with a diagnosis of disc degeneration and root irritation participated in this study. Patients were divided into 3 groups (20 patients in each group), and each group underwent a different physiotherapy program. Continuous short-wave diathermy (CSWD) and exercise were given to the e rst group, 200 Hz PSWD and exercise were applied to the second group while 46 Hz PSWD and exercise were given to the third group. All subjects were evaluated for their pain perception level, muscle strength and lumbar range of motion (ROM). Results showed signie cant improvements in measured parameters in each group after the treatment. However, pain relief, increase in muscular strength and ROM were signie cantly higher in PSWD groups than in those who were treated by continuous diathermy. We concluded that all the interventions used in this study were effective in reducing low back pain but PSWD was found to be more effective than CSWD. summary

Effects of an upper-limb exercise program for improving muscular strength and range of movement on respiratory function of stroke patients.

[Purpose] This study aims to investigate the effects of upper-limb exercises on the respiratory functions of stroke patients. [Subjects and Methods] This study was performed with 25 stroke patients. The subjects were divided into the control group (n=12) which did not perform upper arm training and the experimental group (n=13) which conducted upper arm training. Forced vital capacity and forced expiratory volume in the first second, both of which are used in this study, are well-known indicators of respiratory capabilities. Peak cough flow is used to indicate cough capability. [Results] Concerning changes in forced vital capacity, forced expiratory volume in the first second and the peak cough flow of each group after the exercise, while the control group did not show significant differences, the experimental group showed statistically significant increases. [Conclusion] The results of the study indicate that exercise programs that increase the mobility of upper limbs and increase muscular strength have the effect of normalizing vertebral alignment for stroke patients, and thus can provide effective interventions for improving respiratory function.

STRENGTH TRAINING FOR CHILDREN AND ADOLESCENTS

The potential benefits of youth strength training extend beyond an increase in muscular strength and may include favorable changes in selected health- and fitness-related measures. If appropriate training guidelines are followed, regular participation in a youth strength-training program has the potential to increase bone mineral density, improve motor performance skills, enhance sports performance, and better prepare our young athletes for the demands of practice and competition. Despite earlier concerns regarding the safety and efficacy of youth strength training, current public health objectives now aim to increase the number of boys and girls age 6 and older who regularly participate in physical activities that enhance and maintain muscular fitness. Parents, teachers, coaches, and healthcare providers should realize that youth strength training is a specialized method of conditioning that can offer enormous benefit but at the same time can result in serious injury if established guidelines are not followed. With qualified instruction, competent supervision, and an appropriate progression of the volume and intensity of training, children and adolescents cannot only learn advanced strength training exercises but can feel good about their performances, and have fun. Additional clinical trails involving children and adolescents are needed to further explore the acute and chronic effects of strength training on a variety of anatomical, physiological, and psychological parameters.