Physiological changes with periodized resistance training in women tennis players

PURPOSE: To compare the physiological and performance adaptations between periodized and nonperiodized resistance training in women collegiate tennis athletes. METHODS: Thirty women (19 +/- 1 yr) were assigned to either a periodized resistance training group (P), nonperiodized training group (NV), or a control group (C). Assessments for body composition, anaerobic power, VO2(max), speed, agility, maximal strength, jump height, tennis-service velocity, and resting serum hormonal concentrations were performed before and after 4, 6, and 9 months of resistance training performed 2-3 d.wk (-1). RESULTS: Nine months of resistance training resulted in significant increases in fat-free mass; anaerobic power; grip strength; jump height; one-repetition maximum (1-RM) leg press, bench press, and shoulder press; serve, forehand, and backhand ball velocities; and resting serum insulin-like growth factor-1, testosterone, and cortisol concentrations. Percent body fat and VO2(max) decreased significantly in the P and NV groups after training. During the first 6 months, periodized resistance training elicited significantly greater increases in 1-RM leg press (9 +/- 2 vs 4.5 +/- 2%), bench press (22 +/- 5 vs 11 +/- 8%), and shoulder press (24 +/- 7 vs 18 +/- 6%) than the NV group. The absolute 1-RM leg press and shoulder press values in the P group were greater than the NV group after 9 months. Periodized resistance training also resulted in significantly greater improvements in jump height (50 +/- 9 vs 37 +/- 7%) and serve (29 +/- 5 vs 16 +/- 4%), forehand (22 +/- 3 vs 17 +/- 3%), and backhand ball velocities (36 +/- 4 vs 14 +/- 4%) as compared with nonperiodized training after 9 months. CONCLUSIONS: These data demonstrated that periodization of resistance training over 9 months was superior for enhancing strength and motor performance in collegiate women tennis players.     

Low-volume circuit versus high-volume periodized resistance training in women

PURPOSE: The purpose of this investigation was to determine the long-term training adaptations associated with low-volume circuit-type versus periodized high-volume resistance training programs in women. METHODS: 34 healthy, untrained women were randomly placed into one of the following groups: low-volume, single-set circuit (SSC; N = 12); periodized high-volume multiple-set (MS; N = 12); or nonexercising control (CON) group (N = 10). The SSC group performed one set of 8-12 repetitions to muscular failure 3 d x wk(-1). The MS group performed two to four sets of 3-15 repetitions with periodized volume and intensity 4 d x wk(-1). Muscular strength, power, speed, endurance, anthropometry, and resting hormonal concentrations were determined pretraining (T1), after 12 wk (T2), and after 24 wk of training (T3). RESULTS: 1-RM bench press and leg press, and upper and lower body local muscular endurance increased significantly (P < or = 0.05) at T2 for both groups, but only MS showed a significant increase at T3. Muscular power and speed increased significantly at T2 and T3 only for MS. Increases in testosterone were observed for both groups at T2 but only MS showed a significant increase at T3. Cortisol decreased from T1 to T2 and from T2 to T3 in MS. Insulin-like growth factor-1 increased significantly at T3 for SSC and at T2 and T3 for MS. No changes were observed for growth hormone in any of the training groups. CONCLUSION: Significant improvements in muscular performance may be attained with either a low-volume single-set program or a high-volume, periodized multiple-set program during the first 12 wk of training in untrained women. However, dramatically different training adaptations are associated with specific domains of training program design which contrast in speed of movement, exercise choices and use of variation (periodization) in the intensity and volume of exercise.     

Whole body muscle hypertrophy from resistance training: distribution and total mass

OBJECTIVE: To examine the absolute and relative changes in skeletal muscle (SM) size using whole body magnetic resonance imaging (MRI) in response to heavy resistance training (RT). METHOD: Three young men trained three days a week for 16 weeks. RESULTS: MRI measured total SM mass and fat free mass (FFM) had increased by 4.2 kg and 2.6 kg respectively after resistance training. CONCLUSIONS: RT induces larger increases in SM mass than in FFM. RT induced muscle hypertrophy does not occur uniformly throughout each individual muscle or region of the body. Therefore the distribution of muscle hypertrophy and total SM mass are important for evaluating the effects of total body RT on muscle size.     

Timing of post-exercise protein intake is important for muscle hypertrophy with resistance training in elderly humans

(1) Age‐associated loss of skeletal muscle mass and strength can partly be counteracted by resistance training, causing a net synthesis of muscular proteins. Protein synthesis is influenced synergistically by post‐exercise amino acid supplementation, but the importance of the timing of protein intake remains unresolved. (2) The study investigated the importance of immediate (P0) or delayed (P2) intake of an oral protein supplement upon muscle hypertrophy and strength over a period of resistance training in elderly males. (3) Thirteen men (age 74 ± 1 years; body mass index (BMI), 25 ± 1 kg m^{? 2} (means ± SEM)) completed a 12‐week resistance training program (three times per week) receiving oral protein in liquid form (10 g protein, 7 g carbohydrate, 3 g fat) immediately after (P0) or 2 h after (P2) each training session. Muscle hypertrophy was evaluated by magnetic resonance imaging (MRI) and from muscle biopsies and muscle strength was determined using dynamic and isokinetic strength measurements. Body composition was determined from dual‐energy X‐ray absorptiometry (DEXA) and food records were obtained over 4 days. The plasma insulin response to protein supplementation was also determined. (4) In response to training, the cross‐sectional area of m. quadriceps femoris (54.6 ± 0.5–58.3 ± 0.5 cm²) and mean fiber area (4047 ± 320–5019 ± 615 μ m²) increased in the P0 group, whereas no significant increase was observed in P2. For P0 both dynamic and isokinetic strength increased, by 46 and 15%, respectively (P < 0.05), whereas P2 only improved in dynamic strength, by 36% (P < 0.05). No differences in glucose or insulin response were observed between protein intake at 0 and 2 h post‐exercise. (5) We conclude that early intake of an oral protein supplement after resistance training is important for the development of hypertrophy in skeletal muscle of elderly men in response to resistance training.     

Effects of whey isolate, creatine, and resistance training on muscle hypertrophy

PURPOSE: Studies that have attributed gains in lean body mass to dietary supplementation during resistance exercise (RE) training have not reported these changes alongside adaptations at the cellular and subcellular levels. Therefore, the purpose of this study was to examine the effects of two popular supplements--whey protein (WP) and creatine monohydrate (CrM) (both separately and in combination)--on body composition, muscle strength, fiber-specific hypertrophy (i.e., type I, IIa, IIx), and contractile protein accrual during RE training. METHODS: In a double-blind randomized protocol, resistance-trained males were matched for strength and placed into one of four groups: creatine/carbohydrate (CrCHO), creatine/whey protein (CrWP), WP only, or carbohydrate only (CHO) (1.5 g x kg(-1) body weight per day). All assessments were completed the week before and after an 11-wk structured, supervised RE program. Assessments included strength (1RM, three exercises), body composition (DEXA), and vastus lateralis muscle biopsies for determination of muscle fiber type (I, IIa, IIx), cross-sectional area (CSA), contractile protein, and creatine (Cr) content. RESULTS: Supplementation with CrCHO, WP, and CrWP resulted in significantly greater (P < 0.05) 1RM strength improvements (three of three assessments) and muscle hypertrophy compared with CHO. Up to 76% of the strength improvements in the squat could be attributed to hypertrophy of muscle involved in this exercise. However, the hypertrophy responses within these groups varied at the three levels assessed (i.e., changes in lean mass, fiber-specific hypertrophy, and contractile protein content). CONCLUSIONS: Although WP and/or CrM seem to promote greater strength gains and muscle morphology during RE training, the hypertrophy responses within the groups varied. These differences in skeletal muscle morphology may have important implications for various populations and, therefore, warrant further investigation.     

Blood flow restricted and traditional resistance training performed to fatigue produce equal muscle hypertrophy

This study investigated the hypertrophic potential of load‐matched blood‐flow restricted resistance training (BFR) vs free‐flow traditional resistance training (low‐load TRT) performed to fatigue. Ten healthy young subjects performed unilateral BFR and contralateral low‐load TRT elbow flexor dumbbell curl with 40% of one repetition maximum until volitional concentric failure 3 days per week for 6 weeks. Prior to and at 3 (post‐3) and 10 (post‐10) days post‐training, magnetic resonance imaging (MRI) was used to estimate elbow flexor muscle volume and muscle water content accumulation through training. Acute changes in muscle thickness following an early vs a late exercise bout were measured with ultrasound to determine muscle swelling during the immediate 0–48 h post‐exercise. Total work was threefold lower for BFR compared with low‐load TRT (P < 0.001). Both BRF and low‐load TRT increased muscle volume by approximately 12% at post‐3 and post‐10 (P < 0.01) with no changes in MRI‐determined water content. Training increased muscle thickness during the immediate 48 h post‐exercise (P < 0.001) and to greater extent with BRF (P < 0.05) in the early training phase. In conclusion, BFR and low‐load TRT, when performed to fatigue, produce equal muscle hypertrophy, which may partly rely on transient exercise‐induced increases in muscle water content.     

Isokinetic resistance training combined with eccentric overload improves athletic performance and induces muscle hypertrophy in young ice hockey players

ObjectivesTo determine the combined effects of slow isokinetic resistance training and eccentric overload and compare it to traditional resistance training on strength, power, body composition and muscle hypertrophy in young ice hockey players.DesignExperimental, randomized trial.MethodsTwenty-two resistance-trained ice hockey players (18 ± 1 year) were assigned to either isokinetic resistance training and eccentric overload (ISO/ECC; n = 11) or traditional resistance training (TRAD; n = 11). Participants underwent supervised progressive resistance training for 8 weeks (2–3 sessions/week) involving lower body multiple-joint exercises (heavy squats and explosive jump squats). The ISO/ECC group performed their training using a computerized robotic engine system (1080 Quantum synchro, Sweden), whereas the TRAD group performed the same resistance exercises with isotonic loading. Before and after the intervention, participants were evaluated in 1RM back squat, loaded jump squats, sprint- and jump performance, body composition and muscle thickness using ultrasound measurement.ResultsSimilar moderate increases in 1RM back squat and power output in the jump squats were found in both the ISO/ECC and TRAD groups (11–17%, P < 0.01), whereas only the ISO/ECC group showed improvements in drop jump performance (9.8%, P = 0.01). Moreover, similar trivial changes in body composition were observed in both groups, while only the ISO/ECC training group increased muscle thickness in the vastus intermedius (P = 0.01) and rectus femoris muscles (P = 0.03).ConclusionsBoth modalities effectively increased maximal strength and power output, whereas isokinetic resistance training, combined with eccentric overload, improved drop jump performance and induced greater muscle hypertrophy than traditional training in young ice hockey players.     

Effects of high‐intensity interval cycling performed after resistance training on muscle strength and hypertrophy

Aim of the study was to investigate whether high‐intensity interval cycling performed immediately after resistance training would inhibit muscle strength increase and hypertrophy expected from resistance training per se. Twenty‐two young men were assigned into either resistance training (RE; N = 11) or resistance training plus high‐intensity interval cycling (REC; N = 11). Lower body muscle strength and rate of force development (RFD), quadriceps cross‐sectional area (CSA) and vastus lateralis muscle architecture, muscle fiber type composition and capillarization, and estimated aerobic capacity were evaluated before and after 8 weeks of training (2 times per week). Muscle strength and quadriceps CSA were significantly and similarly increased after both interventions. Fiber CSA increased significantly and similarly after both RE (type I: 13.6 ± 3.7%, type IIA: 17.6 ± 4.4%, type IIX: 23.2 ± 5.7%, P < 0.05) and REC (type I: 10.0 ± 2.7%, type IIA: 14.8 ± 4.3% type IIX: 20.8 ± 6.0%, P < 0.05). In contrast, RFD decreased and fascicle angle increased (P < 0.05) only after REC. Capillary density and estimated aerobic capacity increased (P < 0.05) only after REC. These results suggest that high‐intensity interval cycling performed after heavy‐resistance exercise may not inhibit resistance exercise‐induced muscle strength/hypertrophy after 2 months of training, while it prompts aerobic capacity and muscle capillarization. The addition of high‐intensity cycling after heavy‐resistance exercise may decrease RFD partly due to muscle architectural changes.     

Effects of resistance training and detraining on muscle strength and blood lipid profiles in postmenopausal women

OBJECTIVES: To study the effects of eight weeks of supervised, low intensity resistance training (80% of 10 repetition maximum (10RM)) and eight weeks of detraining on muscle strength and blood lipid profiles in healthy, sedentary postmenopausal women. SUBJECTS: Fifteen postmenopausal women, aged 49-62 years, took part in the study. Subjects were assigned to either a control (n = 7) or training (n = 8) group. The training regimen consisted of three sets of eight repetitions of leg press, bench press, knee extension, knee flexion, and lat pull-down, three days a week at 80% of 10RM. Dynamic leg strength, 10RM, and blood lipid profiles (total cholesterol (TC), low and high density lipoprotein cholesterol (LDL-C, HDL-C), triglycerides, and very low density lipoprotein cholesterol (VLDL-C)) were measured at baseline, after eight weeks of training, and after a further eight weeks of detraining. RESULTS: Eight weeks of resistance training produced significant increases in knee extension (F(1,13) = 12.60; p<0.01), bench press (F(1,13) = 13.79; p<0.01), leg press (F(1,13) = 15.65; p<0.01), and lat pull-down (F(1,13) = 16.60; p<0.005) 10RM strength tests. Although 10RM strength decreased after eight weeks of detraining, the results remained significantly elevated from baseline measures. Eight weeks of training did not result in any significant alterations in blood lipid profiles, body composition, or dynamic isokinetic leg strength. There were no significant differences in any of the variables investigated over the 16 week period in the control group. CONCLUSIONS: These data suggest that a short, low intensity resistance training programme produces substantial improvements in muscle strength. Training of this intensity and duration was not sufficient to produce significant alterations in blood lipid concentrations.     

Unilateral temporalis muscle hypertrophy with contralateral masseteric hypertrophy

We report the MRI findings of a 22-year-old woman who complained of localized swelling in the left temporal region and right side of the face. MRI revealed left temporal and right masseter muscle hypertrophy, which to our knowledge has not been reported previously. The diagnosis of benign masticatory muscle hypertrophy was confirmed by biopsy.     

Enhanced satellite cell proliferation with resistance training in elderly men and women

In addition to the well-documented loss of muscle mass and strength associated with aging, there is evidence for the attenuating effects of aging on the number of satellite cells in human skeletal muscle. The aim of this study was to investigate the response of satellite cells in elderly men and women to 12 weeks of resistance training. Biopsies were collected from the m. vastus lateralis of 13 healthy elderly men and 16 healthy elderly women (mean age 76+/-SD 3 years) before and after the training period. Satellite cells were visualized by immunohistochemical staining of muscle cross-sections with a monoclonal antibody against neural cell adhesion molecule (NCAM) and counterstaining with Mayer's hematoxylin. Compared with the pre-training values, there was a significant increase (P<0.05) in the number of NCAM-positively stained cells per fiber post-training in males (from 0.11+/-0.03 to 0.15+/-0.06; mean+/-SD) and females (from 0.11+/-0.04 to 0.13+/-0.05). These results suggest that 12 weeks of resistance training is effective in enhancing the satellite cell pool in skeletal muscle in the elderly.     

Moderate resistance training and vascular health in overweight women

PURPOSE: Impaired endothelial function has been implicated as an initial step in the pathogenesis of atherosclerosis leading to cardiovascular disease (CVD). Aerobic exercise improves vascular function and reduces risk of CVD morbidity and mortality; however, the effects of resistance training on vascular function remains unclear. Thus, the aim of this study was to examine the effects of 1 yr of resistance training (RT) on vascular structure and function in overweight but otherwise healthy eumenorrheic women. METHODS: Study participants consisted of 30 (15 control, 15 RT) overweight (BMI > 25 kg x m(-2)) women, aged 24-44 yr, studied before and after a 1-yr RT intervention. Vascular structure and function were assessed via noninvasive ultrasound imaging of the carotid and brachial arteries, respectively. Body composition, blood pressure, and fasting blood lipids and glucose also were measured. RESULTS: The RT group demonstrated a significant mean improvement in one-repetition maximum bench press following 1 yr of RT (P < 0.05). There also was a significant increase in lean body mass in the RT group compared with the control group (P = 0.04). There were no training-associated changes in blood pressure, fasting blood lipids, glucose, or insulin levels. Although there was no change in carotid artery intimamedia thickness, peak flow-mediated dilation significantly improved in the RT group (P < 0.05). CONCLUSION: The principal significant finding in this study was the initial demonstration that RT alone can improve brachial artery endothelial function in overweight eumenorrheic women.     

Effects of supplement timing and resistance exercise on skeletal muscle hypertrophy

PURPOSE: Some studies report greater muscle hypertrophy during resistance exercise (RE) training from supplement timing (i.e., the strategic consumption of protein and carbohydrate before and/or after each workout). However, no studies have examined whether this strategy provides greater muscle hypertrophy or strength development compared with supplementation at other times during the day. The purpose of this study was to examine the effects of supplement timing compared with supplementation in the hours not close to the workout on muscle-fiber hypertrophy, strength, and body composition during a 10-wk RE program. METHODS: In a single-blind, randomized protocol, resistance-trained males were matched for strength and placed into one of two groups; the PRE-POST group consumed a supplement (1 g x kg(-1) body weight) containing protein/creatine/glucose immediately before and after RE. The MOR-EVE group consumed the same dose of the same supplement in the morning and late evening. All assessments were completed the week before and after 10 wk of structured, supervised RE training. Assessments included strength (1RM, three exercises), body composition (DEXA), and vastus lateralis muscle biopsies for determination of muscle fiber type (I, IIa, IIx), cross-sectional area (CSA), contractile protein, creatine (Cr), and glycogen content. RESULTS: PRE-POST demonstrated a greater (P < 0.05) increase in lean body mass and 1RM strength in two of three assessments. The changes in body composition were supported by a greater (P < 0.05) increase in CSA of the type II fibers and contractile protein content. PRE-POST supplementation also resulted in higher muscle Cr and glycogen values after the training program (P < 0.05). CONCLUSION: Supplement timing represents a simple but effective strategy that enhances the adaptations desired from RE-training.     

Concentric resistance training increases muscle strength without affecting microcirculation

Purpose

While the evidence is conclusive regarding the positive effects of endurance training, there is still some controversy regarding the effects of resistance training on muscular capillarity. Thus, the purpose was to assess whether resistance strength training influences resting skeletal muscle microcirculation in vivo.

Materials and methods

Thirty-nine middle-aged subjects (15 female, 24 male; mean age, 54 ± 9 years) were trained twice a week on an isokinetic system (altogether 16 sessions lasting 50 min, intensity 75% of maximum isokinetic and isometric force of knee flexors and extensors). To evaluate success of training, cross-sectional area (CSA) of the quadriceps femoris muscle and its isokinetic and isometric force were quantified. Muscular capillarization was measured in biopsies of the vastus lateralis muscle. In vivo, muscular energy and lipid metabolites were quantified by magnetic resonance spectroscopy and parameters of muscular microcirculation, such as local blood volume, blood flow and velocity, by contrast-enhanced ultrasound analyzing replenishment kinetics.

Results

The significant (P < 0.001) increase in CSA (60 ± 16 before vs. 64 ± 15 cm² after training) and in absolute muscle strength (isometric, 146 ± 44 vs. 174 ± 50 Nm; isokinetic, 151 ± 53 vs. 174 ± 62 Nm) demonstrated successful training. Neither capillary density ex vivo (351 ± 75 vs. 326 ± 62) nor ultrasonographic parameters of resting muscle perfusion were significantly different (blood flow, 1.2 ± 1.2 vs. 1.1 ± 1.1 ml/min/100 g; blood flow velocity, 0.49 ± 0.44 vs. 0.52 ± 0.74 mm s⁻¹). Also, the intensities of high-energy phosphates phosphocreatine and β-adenosintriphosphate were not different after training within the skeletal muscle at rest (β-ATP/phosphocreatine, 0.29 ± 0.06 vs. 0.28 ± 0.04).

Conclusion

The significant increase in muscle size and strength in response to concentric isokinetic and isometric resistance training occurs without an increase in the in vivo microcirculation of the skeletal muscles at rest.     

Resistance training frequency and skeletal muscle hypertrophy: A review of available evidence

Objectives

Current reviews and position stands on resistance training (RT) frequency and associated muscular hypertrophy are based on limited evidence holding implications for practical application and program design. Considering that several recent studies have shed new light on this topic, the present paper aimed to collate the available evidence on RT frequency and the associated effect on muscular hypertrophy.

Effects of aquatic resistance training on neuromuscular performance in healthy women

PURPOSE: The purpose of this study was to investigate the effects of a progressive 10-wk aquatic resistance training on neuromuscular performance and muscle mass of the knee extensors and flexors in healthy women. METHODS: Twenty-four healthy women (34.2 +/- 3.9 yr) were randomly assigned into aquatic exercise (N = 12) and control group (N = 12). Maximum knee extension and flexion torques were measured isometrically and at constant angular velocities of 60 degrees x s(-1) and 180 degrees x s(-1) (isokinetic) with simultaneous electromyography (EMG) recordings of the quadriceps and hamstrings. The lean muscle mass (LCSA) of the quadriceps and hamstring muscles was determined by computed tomography scanning. RESULTS: Significant interaction of group by time was observed in each of the measured parameters. The change in extension and flexion isometric/isokinetic torque varied between 8 and 13% and in EMGs between 10 and 27% in the exercise group. The change in the quadriceps LCSA of the exercise group was 4% and in hamstrings 5.5%. CONCLUSIONS: The results of the present study showed that 10 wk of progressive aquatic resistance training resulted in significant improvement in muscle torque of the knee extensors and flexors accompanied with proportional improvement in neural activation and with significant increase in the LCSA of the trained muscles. Aquatic training can be recommended for neuromuscular conditioning in healthy persons.