Yoga as steadiness training: effects on motor variability in young adults

Exercise training programs can increase strength and improve submaximal force control, but the effects of yoga as an alternative form of steadiness training are not well described. The purpose was to explore the effect of a popular type of yoga (Bikram) on strength, steadiness, and balance. Young adults performed yoga training (n = 10, 29 +/- 6 years, 24 yoga sessions in 8 weeks) or served as controls (n = 11, 26 +/- 7 years). Yoga sessions consisted of 1.5 hours of supervised, standardized postures. Measures before and after training included maximum voluntary contraction (MVC) force of the elbow flexors (EF) and knee extensors (KE), steadiness of isometric EF and KE contractions, steadiness of concentric (CON) and eccentric (ECC) KE contractions, and timed balance. The standard deviation (SD) and coefficient of variation (CV, SD/mean force) of isometric force and the SD of acceleration during CON and ECC contractions were measured. After yoga training, MVC force increased 14% for KE (479 +/- 175 to 544 +/- 187 N, p < 0.05) and was unchanged for the EF muscles (219 +/- 85 to 230 +/- 72 N, p > 0.05). The CV of force was unchanged for EF (1.68 to 1.73%, p > 0.05) but was reduced in the KE muscles similarly for yoga and control groups (2.04 to 1.55%, p < 0.05). The variability of CON and ECC contractions was unchanged. For the yoga group, improvement in KE steadiness was correlated with pretraining steadiness (r = -0.62 to -0.84, p < 0.05); subjects with the greatest KE force fluctuations before training experienced the greatest reductions with training. Percent change in balance time for individual yoga subjects averaged +228% (19.5 +/- 14 to 34.3 +/- 18 seconds, p < 0.05), with no change in controls. For young adults, a short-term yoga program of this type can improve balance substantially, produce modest improvements in leg strength, and improve leg muscle control for less-steady subjects.     

Effects of 4 weeks of traditional resistance training vs. superslow strength training on early phase adaptations in strength, flexibility, and aerobic capacity in college-aged women

This study compared SuperSlow resistance training (SRT) to traditional resistance training (TRT) during early phase adaptations in strength, aerobic capacity, and flexibility in college-aged women. Subjects were randomly assigned to SRT (n = 14); TRT (n = 13); or control (CON; n = 8) groups. To equalize training times, TRT trained 3 times per week for 25 minutes each session, whereas SRT trained twice a week for 35 minutes each session. Both groups trained for 4 weeks, whereas the CON group maintained normal daily activities. Workouts consisted of 5 exercises: shoulder press, chest press, leg press, low row, and lat pull down. The SRT group completed 1 set of each exercise at 50% 1RM until momentary failure with a 10-second concentric and a 10-second eccentric phase. The TRT group completed 3 sets of 8 repetitions at 80% 1RM for each exercise, with 4 seconds of contraction time for each repetition. Groups were statistically similar at baseline. There was a significant (p ≤ 0.01) time main effect for flexibility with the greatest improvements occurring for the training groups (SRT 14.7% and TRT 11%). All strength tests had significant (p ≤ 0.01) time main effects but no group or group by time interactions. Both training groups had large percent improvements in strength compared to CON, but the large variability associated with the SRT group resulted in only the TRT group being significantly different from the CON group. In conclusion, percent improvements were similar for the TRT and SRT groups, but only the TRT group reached statistical significance for the strength improvements, and both groups were equally effective for improving flexibility.     

Effect of concurrent endurance and circuit resistance training sequence on muscular strength and power development

The purpose of this study was to examine the influence of the sequence order of high-intensity endurance training and circuit training on changes in muscular strength and anaerobic power. Forty-eight physical education students (ages, 21.4 +/- 1.3 years) were assigned to 1 of 5 groups: no training controls (C, n = 9), endurance training (E, n = 10), circuit training (S, n = 9), endurance before circuit training in the same session, (E+S, n = 10), and circuit before endurance training in the same session (S+E, n = 10). Subjects performed 2 sessions per week for 12 weeks. Resistance-type circuit training targeted strength endurance (weeks 1-6) and explosive strength and power (weeks 7-12). Endurance training sessions included 5 repetitions run at the velocity associated with Vo2max (Vo2max) for a duration equal to 50% of the time to exhaustion at Vo2max; recovery was for an equal period at 60% Vo2max. Maximal strength in the half squat, strength endurance in the 1-leg half squat and hip extension, and explosive strength and power in a 5-jump test and countermovement jump were measured pre- and post-testing. No significant differences were shown following training between the S+E and E+S groups for all exercise tests. However, both S+E and E+S groups improved less than the S group in 1 repetition maximum (p < 0.01), right and left 1-leg half squat (p < 0.02), 5-jump test (p < 0.01), peak jumping force (p < 0.05), peak jumping power (p < 0.02), and peak jumping height (p < 0.05). The intrasession sequence did not influence the adaptive response of muscular strength and explosive strength and power. Circuit training alone induced strength and power improvements that were significantly greater than when resistance and endurance training were combined, irrespective of the intrasession sequencing.     

Sensory mapping of the upper trapezius muscle in relation to consecutive sessions of eccentric exercise

The aim of this study was to evaluate the changes in pressure pain sensitivity maps in untrained subjects over 2 subsequent sessions of eccentric exercise (ECC) expected to result in (a) delayed onset muscle soreness (DOMS) and (b) adaptation/recovery, respectively. Eleven healthy male subjects participated in this study. Pressure pain threshold (PPT), rate of perceived exertion (RPE), pain intensity, soreness area drawing, maximal voluntary contraction (MVC), and shoulder range of motion were assessed in session 1 before, immediately after, and 24 hours after ECC. The ECC protocol that was used to induce DOMS consisted of 50 eccentric contractions of the right shoulder that were divided into 5 bouts, including 10 contractions at MVC level separated by a 2-minute resting period. Session 2 was identical to session 1 and performed exactly 1 week later. There was only a significant increase in the RPE assessed before the exercise and 24 hours after the exercise in session 1 (p = 0.001). The average PPT only decreased significantly from before the exercise (660.2 ± 76.2 kPa) to 24 hours after the exercise (435.6 ± 59.3 kPa) in session 1 (p = 0.016). The present study confirmed a heterogeneous distribution of mechanical sensitivity before and after sessions of ECC. The first session of ECC underlined increased mechanical sensitivity because of DOMS, whereas the second session reflected an adaptation process. Our results support the potential role of ECC bouts in training regimens.     

Effects of whole-body low-intensity resistance training with slow movement and tonic force generation on muscular size and strength in young men

Our previous study showed that relatively low-intensity (approximately 50% one-repetition maximum [1RM]) resistance training (knee extension) with slow movement and tonic force generation (LST) caused as significant an increase in muscular size and strength as high-intensity (approximately 80% 1RM) resistance training with normal speed (HN). However, that study examined only local effects of one type of exercise (knee extension) on knee extensor muscles. The present study was performed to examine whether a whole-body LST resistance training regimen is as effective on muscular hypertrophy and strength gain as HN resistance training. Thirty-six healthy young men without experience of regular resistance training were assigned into three groups (each n = 12) and performed whole-body resistance training regimens comprising five types of exercise (vertical squat, chest press, latissimus dorsi pull-down, abdominal bend, and back extension: three sets each) with LST (approximately 55-60% 1RM, 3 seconds for eccentric and concentric actions, and no relaxing phase); HN (approximately 80-90% 1RM, 1 second for concentric and eccentric actions, 1 second for relaxing); and a sedentary control group (CON). The mean repetition maximum was eight-repetition maximum in LST and HN. The training session was performed twice a week for 13 weeks. The LST training caused significant (p < 0.05) increases in whole-body muscle thickness (6.8 +/- 3.4% in a sum of six sites) and 1RM strength (33.0 +/- 8.8% in a sum of five exercises) comparable with those induced by HN training (9.1 +/- 4.2%, 41.2 +/- 7.6% in each measurement item). There were no such changes in the CON group. The results suggest that a whole-body LST resistance training regimen is as effective for muscular hypertrophy and strength gain as HN resistance training.     

Maximal eccentric and concentric strength discrepancies between young men and women for dynamic resistance exercise

Although research has demonstrated that isokinetic eccentric (ECC) strength is 20-60% greater than isokinetic concentric (CON) strength, few data exist comparing these strength differences in standard dynamic resistance exercises. The purpose of the study was to determine the difference in maximal dynamic ECC and CON strength for 6 different resistance exercises in young men and women. Ten healthy young men (mean +/- SE, 25.30 +/- 1.34 years), and 10 healthy young women (mean +/- SE, 23.40 +/- 1.37 years) who were regular exercisers with resistance training experience participated in the study. Two sessions were performed to determine CON and ECC 1 repetitions maximum for latissimus pull-down (LTP), leg press (LP), bench press (BP), leg extension (LE), seated military press (MP), and leg curl (LC) exercises. Maximal ECC and maximal CON strength were determined on weight stack machines modified to isolate ECC and CON contractions using steel bars and pulleys such that only 1 type of contraction was performed. Within 2 weeks, participants returned and completed a retest trial in a counterbalanced fashioned. Test-retest reliability was excellent (r = 0.99) for all resistance exercise trials. Men demonstrated 20-60% greater ECC than CON strength (LTP = 32%, LP = 44%, BP = 40%, LE = 35%, MP = 49%, LC = 27%). Women's strength exceeded the proposed parameters for greater ECC strength in 4 exercises, p < 0.05 (LP = 66%, BP = 146%, MP = 161%, LC = 82%). The ECC/CON assessment could help coaches capitalize on muscle strength differences in young men and women during training to aid in program design and injury prevention and to enhance strength development.     

The effects of isokinetic contraction velocity on concentric and eccentric strength of the biceps brachii

The purpose of this investigation was to determine the influence of contraction velocity on the eccentric (ECC) and concentric (CON) torque production of the biceps brachii. After performing warm-up procedures, each male subject (n = 11) completed 3 sets of 5 maximal bilateral CON and ECC isokinetic contractions of the biceps at speeds of 90, 180, and 300 degrees x s(-1) on a Biodex System 3 dynamometer. The men received a 3-minute rest between sets and the order of exercises was randomized. Peak torque (Nm) values were obtained for CON and ECC contractions at each speed. Peak torque scores (ECC vs. CON) were compared using a t-test at each speed. A repeated measures analysis of variance was used to determine differences between speeds. ECC peak torque scores were greater than CON peak torque scores at each given speed: 90 degrees x s(-1), p = 0.0001; 180 degrees x s(-1), p = 0.0001; and 300 degrees x s(-1), p = 0.0001. No differences were found between the ECC peak torque scores (p = 0.62) at any of the speeds. Differences were found among the CON scores (p = 0.004). Post hoc analysis revealed differences between 90 degrees x s(-1) (114.61 +/- 23) and 300 degrees x s(-1) (94.17 +/- 18). These data suggest that ECC contractions of the biceps brachii were somewhat resistant to a force decrement as the result of an increase in velocity, whereas CON muscular actions of the biceps brachii were unable to maintain force as velocity increased.     

Urinary steroid profile after the completion of concentric and concentric/eccentric trials with the same total workload

High intensity strength training causes changes in steroid hormone concentrations. This could be altered by the muscular contraction type: eccentric or concentric. The aim of this study was to compare the effect of the completion of a short concentric (CON) and concentric/eccentric (CON/ECC) trial on the urinary steroid profile, both with the same total work. 18 males performed the trials on an isokinetic dynamometer (BIODEX III) exercising quadriceps muscles, right and left, on different days. Trial 1(CON): 4×10 Concentric knee extension + relax knee flexion, speed 60°/second; rest 90 seconds between each series and 4 minutes between each leg exercise. Trial 2(CON/ECC): 4×5 concentric knee extension + Eccentric knee flexion under similar conditions. Urine samples were taken before the exercise and one hour after finishing it. Androsterone, Etiocholanolone, DHEA, Androstenedione, Testosterone, Epitestosterone, Dehydrotestosterone, Estrone, B-Estradiol, Tetrahydrocortisone, Tetrahydrocortisol, Cortisone and Cortisol (free, glucoconjugated and sulfoconjugated) urinary values were determined using gas chromatography/mass spectrometry techniques. No significant differences were noted in Total Work and Average Peak Torque, although Maximum Peak Torque in the CON/ECC trial was higher than in the CON trial. These results demonstrate no changes in the steroid profile before and after trials, or when comparing CON to CON/ECC trials. The data suggest that eccentric contractions do not cause hormonal changes different to the ones produced by concentric contractions, when they are performed in strength short trials with the same total workload.     

Bilateral eccentric and concentric torque of quadriceps and hamstring muscles in females and males

This study assessed maximum eccentric (ECC) and concentric (CON) torque of quadriceps (QUAD) and hamstring (HAM) muscle groups in healthy females (n = 13) and males (n = 27). Peak torques (PT) of bilateral muscle actions were recorded at constant angular velocities of 0.52, 1.57 and 2.61 rad.s-1. The QUADCON and HAMCON PT decreased (p less than 0.05) with increasing angular velocity. The QUADECC and HAMECC PT increased (p less than 0.05) in females, whereas QUADECC PT decreased (p less than 0.05) and HAMECC PT showed no change in males. In general, ECC PT was higher (p less than 0.05) than CON PT and QUAD PT was higher (p less than 0.05) than HAM PT, for any given angular velocity. Males displayed higher (p less than 0.05) PT than females but when PT were adjusted for body mass the sex differences in QUADCON and HAMCON were reduced (p less than 0.05), whereas the differences in QUADECC and HAMECC were abolished. The CON and ECC PT were, on average, 60% and 41% greater, respectively, in males than in females. The corresponding differences, when adjusted for body mass, were 23% and 8%. ECC:CON PT for QUAD were higher (p less than 0.05) in females than in males. CON and ECC HAM:QUAD PT ratio increased (p less than 0.05), as a function of velocity. This study suggests, that bilateral ECC PT is higher than CON PT and CON HAM:QUAD PT ratio is higher than ECC HAM:QUAD PT ratio.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Jump exercise during remobilization restores integrity of the trabecular architecture after tail suspension in young rats.

Three-dimensional trabecular architecture was investigated in the femora of tail-suspended young growing rats, and the effects of jump exercise during remobilization were examined. Five-week-old male Wistar rats (n = 35) were randomly assigned to five body weight-matched groups: tail-suspended group (SUS; n = 7); sedentary control group for SUS (S(CON); n = 7); spontaneous recovery group after tail suspension (S+R(CON), n = 7); jump exercise group after tail suspension (S+R(JUM); n = 7); and age-matched control group for S+R(CON) and S+R(JUM) without tail suspension and exercise (S(CON)+R(CON); n = 7). Rats in SUS and S(CON) were killed immediately after tail suspension for 14 days. The jump exercise protocol consisted of 10 jumps/day, 5 days/wk, and jump height was 40 cm. Bone mineral density (BMD) of the femur and three-dimensional trabecular bone architecture at the distal femoral metaphysis were measured. Tail suspension induced a 13.6% decrease in total femoral BMD (P < 0.001) and marked deterioration of trabecular architecture. After 5 wk of free remobilization, femoral BMD, calf muscle weight, and body weight returned to age-matched control levels, but trabeculae remained thinner and less connected. On the other hand, S+R(JUM) rats showed significant increases in trabecular thickness, number, and connectivity compared with S+R(CON) rats (62.8, 31.6, and 24.7%, respectively; P < 0.05), and these parameters of trabecular architecture returned to the levels of S(CON)+R(CON). These results indicate that suspension-induced trabecular deterioration persists after remobilization, but jump exercise during remobilization can restore the integrity of trabecular architecture and bone mass in the femur in young growing rats.     

A comparison of cluster-based exposure variation and exposure variation analysis to detect muscular adaptation in the shoulder joint to subsequent sessions of eccentric exercise during computer work

The aim of this study was to compare the capability of a cluster-based exposure variation (C-EVA) with a conventional exposure variation analysis (EVA) to detect muscular adaptation in the shoulder joint to subsequent sessions of eccentric exercise (ECC). Eleven healthy subjects performed work with a computer mouse for 10 min at three instants, i.e., before, immediately after, and 24 h after ECC. The subjects repeated an identical procedure one week after the first session. Surface electromyography was recorded from descending and ascending part of the trapezius, deltoid anterior, and serratus anterior muscles. EVA and C-EVA were performed and their marginal distributions were extracted. A principal component analysis was applied to the marginal distributions of both EVA and C-EVA. Principal component difference was computed by subtraction of the corresponding principal components before the ECC from immediately after and 24 h after the ECC. The first component extracted from C-EVA revealed an interactive effect between the sessions of ECC and instants whereas this effect was absent using the conventional EVA. The current study highlights the importance of a multivariate approach to analyze the potentially important changes in muscular activity in response to the repeated bout effect.     

Reduced susceptibility to eccentric exercise-induced muscle damage in resistance-trained men is not linked to resistance training-related neural adaptations

The purpose of this study was to examine the acute effects of maximal concentric vs. eccentric exercise on the isometric strength of the elbow flexor, as well as the biceps brachii muscle electromyographic (EMG) responses in resistance-trained (RT) vs. untrained (UT) men. Thirteen RT men (age: 24 ± 4 years; height: 180.2 ± 7.7 cm; body weight: 92.2 ± 16.9 kg) and twelve UT men (age: 23 ± 4 years; height: 179.2 ± 5.0 cm; body weight: 81.5 ± 8.6 kg) performed six sets of ten maximal concentric isokinetic (CON) or eccentric isokinetic (ECC) elbow flexion exercise in two separate visits. Before and after the exercise interventions, maximal voluntary contractions (MVCs) were performed for testing isometric strength. In addition, bipolar surface EMG signals were detected from the biceps brachii muscle during the strength testing. Both CON and ECC caused isometric strength to decrease, regardless of the training status. However, ECC caused greater isometric strength decline than CON did for the UT group (p = 0.006), but not for the RT group. Both EMG amplitude and mean frequency significantly decreased and increased, respectively, regardless of the training status and exercise intervention. Resistance-trained men are less susceptible to eccentric exercise-induced muscle damage, but this advantage is not likely linked to the chronic resistance training-induced neural adaptations.     

The effects of resistance training performed in water on muscle strength in the elderly

The purpose of the present study was to compare the effects of a program of resistance training in water-based exercises (RWE) with those of a program without resistance control in water-based exercises (WEs). Twenty-seven women (aged 60-74 years) were randomly assigned to the RWE group (n = 10), WE group (n = 10), or nontraining control (CON) group (n = 7). The RWE and WE groups trained classes with aerobic exercises and localized muscular resistance exercises for 50 minutes, twice a week for 12 weeks. For the RWE group, the program included 4 mesocycles of 3 weeks-respectively, 4 sets of 15 repetitions, 4 sets of 12 repetitions, 5 sets of 10 repetitions, and 5 sets of 8 repetitions-of shoulder horizontal flexion exercise at maximum speed, with the use of resistive equipment. For the WE group, the training was not periodized, and the resistance in the localized muscular exercises was not controlled. One repetition maximum (1RM) was measured on a pectoral fly machine at baseline and after the training period. The level of significance adopted was p ≤ 0.05. The results showed that the only significant increase in 1RM (10.89%, p < 0.001) occurred in the RWE group after training. In conclusion, these findings suggest that WEs with emphasis on resistance training in a periodized program can efficiently increase maximum strength in elderly women. Thus, it is suggested that the strategies used in WE programs be modified to offer suitable stimuli for the development of strength.     

Effect of different types of conditioning contraction on upper body postactivation potentiation

Muscle contractions preceding an activity can result in increased force generation (postactivation potentiation [PAP]). Although the type of muscular contractions could affect subsequent strength and power performance, little information exists on their effects. The purpose of this study was to examine PAP effects produced by isometric (ISO), concentric (CON), eccentric (ECC), or concentric-eccentric (DYN) conditioning contractions on upper body force and power performance. Ten male, competitive rugby players (mean ± SD: age 20.4 ± 0.8 years, height 177.0 ± 8.1 cm, body mass 90.2 ± 13.8 kg) performed a ballistic bench press throw (BBPT) followed by a 10-minute rest and one of the conditioning contractions. After a 12-minute rest, the subjects performed another BBPT (post-BBPT). The conditioning contractions, applied on separate days and in counterbalanced randomized order, were a 7-second isometric barbell bench press for ISO and 1 set of 3 bench press repetitions at 3 repetition maximum for CON, ECC, and DYN (each repetition lasting 2 seconds for CON and ECC, overall execution time <7 seconds for DYN). Peak power (Ppeak), peak force (Fpeak), maximum distance (Dmax) and rate of force development (RFD) were measured using a linear position transducer. Electromyography (EMG) of the pectoralis major and triceps brachii was also recorded. The ISO produced significantly higher Ppeak (587 ± 116 and 605 ± 126 W for pre- and post-BBPT, respectively; p < 0.05). No significant differences in Ppeak were revealed for CON, ECC, and DYN (p > 0.05), and no significant differences existed in Fpeak, Dmax, and RFD for ISO, CON, ECC, and DYN (p > 0.05). Finally, EMG was not significantly different between pre- and post-BBPT for any of the conditioning contractions (p > 0.05). Isometric contractions appear to be the only conditioning contractions increasing upper body power output after long resting periods.     

Short-term strength training and the expression of myostatin and IGF-I isoforms in rat muscle and tendon: differential effects of specific contraction types.

In skeletal muscle, an increased expression of insulin like growth factor-I isoforms IGF-IEa and mechano-growth factor (MGF) combined with downregulation of myostatin is thought to be essential for training-induced hypertrophy. However, the specific effects of different contraction types on regulation of these factors in muscle are still unclear, and in tendon the functions of myostatin, IGF-IEa, and MGF in relation to training are unknown. Female Sprague-Dawley rats were subjected to 4 days of concentric, eccentric, or isometric training (n = 7-9 per group) of the medial gastrocnemius, by stimulation of the sciatic nerve during general anesthesia. mRNA levels for myostatin, IGF-IEa, and MGF in muscle and Achilles' tendon were measured by real-time RT-PCR. Muscle myostatin mRNA decreased in response to all types of training (2- to 8-fold) (P < 0.05), but the effect of eccentric training was greater than concentric and isometric training (P < 0.05). In tendon, myostatin mRNA was detected, but no changes were seen after exercise. IGF-IEa and MGF increased in muscle (up to 15-fold) and tendon (up to 4-fold) in response to training (P < 0.01). In tendon no difference was seen between training types, but in muscle the effect of eccentric training was greater than concentric training for both IGF-IEa and MGF (P < 0.05), and for IGF-IEa isometric training had greater effect than concentric (P < 0.05). The results indicate a possible role for IGF-IEa and MGF in adaptation of tendon to training, and the combined changes in myostatin and IGF-IEa/MGF expression could explain the important effect of eccentric actions for muscle hypertrophy.     

Early-phase neuroendocrine responses and strength adaptations following eccentric-enhanced resistance training

The purpose of this study was to evaluate the early-phase muscular performance adaptations to 5 weeks of traditional (TRAD) and eccentric-enhanced (ECC+) progressive resistance training and to compare the acute postexercise total testosterone (TT), bioavailable testosterone (BT), growth hormone (GH), and lactate responses in TRAD- and ECC+-trained individuals. Twenty-two previously untrained men (22.1 +/- 0.8 years) completed 1 familiarization and 2 baseline bouts, 15 exercise bouts (i.e., 3 times per week for 5 weeks), and 2 postintervention testing bouts. Anthropometric and 1 repetition maximum (1RM) measurements (i.e., bench press and squat) were assessed during both baseline and postintervention testing. Following baseline testing, participants were randomized into TRAD (4 sets of 6 repetitions at 52.5% 1RM) or ECC+ (3 sets of 6 repetitions at 40% 1RM concentric and 100% 1RM eccentric) groups and completed the 5-week progressive resistance training protocols. During the final exercise bout, blood samples acquired at rest and following exercise were assessed for serum TT, BT, GH, and blood lactate. Both groups experienced similar increases in bench press (approximately 10%) and squat (approximately 22%) strength during the exercise intervention. At the conclusion of training, postexercise TT and BT concentrations increased (approximately 13% and 21%, respectively, p < 0.05) and GH concentrations increased (approximately 750-1200%, p < 0.05) acutely following exercise in both protocols. Postexercise lactate accumulation was similar between the TRAD (5.4 +/- 0.4) and ECC+ (5.6 +/- 0.4) groups; however, the ECC+ group's lactate concentrations were significantly lower than those of the TRAD group 30 to 60 minutes into recovery. In conclusion, TRAD training and ECC+ training appear to result in similar muscular strength adaptations and neuroendocrine responses, while postexercise lactate clearance is enhanced following ECC+ training.     

The effects of yoga training and a single bout of yoga on delayed onset muscle soreness in the lower extremity

The purpose of this study was to determine the effects of yoga training and a single bout of yoga on the intensity of delayed onset muscle soreness (DOMS). 24 yoga-trained (YT; n = 12) and non-yoga-trained (CON; n = 12), matched women volunteers were administered a DOMS-inducing bench-stepping exercise. Muscle soreness was assessed at baseline, 24, 48, 72, 96, and 120 hours after bench-stepping using a Visual Analog Scale (VAS). Groups were also compared on body awareness (BA), flexibility using the sit-and-reach test (SR), and perceived exertion (RPE). Statistical significance was accepted at p 相似文献