Resistance Training Period Research Articles

Effects of order of resistance training exercises on muscle hypertrophy in young adult men

The purpose of the present study was to analyze the effects of the order of resistance training (RT) exercises on hypertrophy in young adult men. Thirty-six young adult men (age, 21.9 ± 2.5 years; body mass, 72.6 ± 12.1 kg, height, 176.9 ± 7.4 cm; body mass index, 23.1 ± 3.3 kg/m2) were randomly assigned to 1 of 2 training groups that performed a 6-week RT program in either (i) a traditional approach starting with multi-joint (MJ) exercises followed by single-joint exercises (SJ) (MJ-SJ, n = 19) or (ii) in reverse order (SJ-MJ, n = 17). Muscle thickness of the biceps brachii and mid-thigh were assessed by ultrasound. Lean soft tissue (LST) was assessed by dual-energy X-ray absorptiometry. Both groups similarly increased (P < 0.05) biceps brachii thickness (MJ-SJ = +14.2%, SJ-MJ = +13.8%). Alternatively, only the MJ-SJ group presented an increase in mid-thigh thickness from pre- to post-training (MJ-SJ = +7.2%, SJ-MJ = +3.9%). Upper limb LSTs (MJ-SJ = +5.2%, SJ-MJ = +7.5%) were statistically similar between conditions, and a trend for significance (P = 0.07) was found for trunk LST (MJ-SJ = +7.2%, SJ-MJ = +1.7%). Nonsignificant pre- to post-training changes were observed for lower limb LSTs (MJ-SJ = +0.7%, SJ-MJ = +1.8%). Our data suggest that both sequences are effective for increasing muscle hypertrophy over a short-term RT period; there may be a potentially beneficial hypertrophic effect for the mid-thigh by performing exercises in a manner that progresses from MJ to SJ exercises.

Exercise recovery increases skeletal muscle H2O2 emission and mitochondrial respiratory capacity following two-weeks of limb immobilization

Extended periods of skeletal muscle disuse result in muscle atrophy. Following limb immobilization, increased mitochondrial reactive oxygen species (ROS) production may contribute to atrophy through increases in skeletal muscle protein degradation. However, the effect of skeletal muscle disuse on mitochondrial ROS production remains unclear. This study investigated the effect of immobilization, followed by two subsequent periods of restored physical activity, on mitochondrial H2O2 emissions in adult male skeletal muscle. Middle-aged men (n = 30, 49.7 ± 3.84 y) completed two weeks of unilateral lower-limb immobilization, followed by two weeks of baseline-matched activity, consisting of 10,000 steps a day, then completed two weeks of three times weekly supervised resistance training. Vastus lateralis biopsies were taken at baseline, post-immobilization, post-ambulatory recovery, and post-resistance-training. High-resolution respirometry was used simultaneously with fluorometry to determine mitochondrial respiration and hydrogen peroxide (H2O2) production in permeabilized muscle fibres. Mitochondrial H2O2 emission with complex I and II substrates, in the absence of ADP, was greater following immobilization, however, there was no effect on mitochondrial respiration. Both ambulatory recovery and resistance training, following the period of immobilization, increased in mitochondrial H2O2 emissions. These data demonstrated that 2 weeks of immobilization increases mitochondrial H2O2 emissions, but subsequent retraining periods of ambulatory recovery and resistance training also led to in robust increases in mitochondrial H2O2 emissions in skeletal muscle.

Non-Linear Resistance Training Program Induced Power and Strength but Not Linear Sprint Velocity and Agility Gains in Young Soccer Players.

Background: The present study evaluated the effects of resistance training (RT) following a non-linear periodization model in the physical fitness of young soccer athletes. Methods: Young soccer players (n = 23) were allocated into two groups: an RT group (RTG), and the control group (CON). The RTG underwent 15 weeks of non-linear RT periodization in three weekly sessions in addition to their specific soccer training. The CON continued performing the specific soccer training. Before and after the training period, all of the subjects performed one-repetition maximum (RM) tests for speed, agility, and power (vertical and horizontal jump). Results: The RTG obtained significant gains in one-RM tests (before 64.1 ± 5.8 kg, after 79.1 ± 3.3 kg) and power (vertical jump (before 56 ± 2.7 cm, after 61.3 ± 1.7 cm) and horizontal jump (before 184.5 ± 5.5 cm, after 213.6 ± 3.2 cm)). In contrast, the CON group presented a non-significant increase in one-RM tests and horizontal jump, and a significant reduction in vertical jump (before 55.4 ± 2.2 cm, after 51.3 ± 1.5 cm). Neither group presented significant gains in speed (CON: p = 0.27; RTG: p = 0.72) and agility (CON: p = 0.19; RTG: p = 0.58). Conclusion: Our data suggest that non-linear RT should be inserted into the routine of young soccer athletes for improving strength and power without impairing speed and agility.

Muscle protein synthesis during the early period of resistance training in rat

Increase in muscle protein synthesis (MPS) by resistance exercise (RE) has been thought to be caused by increases in translational efficiency (major regulator: mammalian target of rapamycin (mTOR) signaling pathway) and translational capacity (ribosome content).It has been shown that repeated bouts of RE leads to the attenuation of the activation of mTOR signaling and the increase in ribosome content after a bout of RE (Ogasawara et al. 2013). However, it is unknown whether MPS response to RE is also declined when exercise bout is repeated.PurposeTo see if the acclimatization occurs in the response of protein metabolism to exercise during the course of RE , the present study investigated the changes in MPS, mTOR signaling pathway and ribosome content with the increase of RE bout.MethodMale Sprague‐Dawley rats were randomly assigned into three groups: Sedentary (SED), resistance‐trained with 1 bout (1B), 3 bouts (3B). RE protocol consisted of 50 repetitions of maximal isometric contraction of the gastrocnemius muscle elicited by direct electric stimulation under anesthesia. A day recovery period was taken between each bout. Muscle samples were collected 6h after the last RE session.ResultsAmount of puromycin‐labeled peptides was larger in trained groups than in SED, but no significant difference was seen between 1B and 3B. Posphorylation of p70S6K was larger in trained groups than in SED, and significantly larger in 1B than in 3B. By contrast, ribosomal RNA content was larger in trained groups than in SED, and significantly larger in 3B than in 1B.ConclusionMPS after repeated bouts of RE was unchanged from that after a single bout in spite of the attenuated response of mTOR signaling. This may be caused by the compensatory increase in ribosome content with the increase in the exercise bout.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of functional resistance training on fitness and quality of life in females with chronic nonspecific low-back pain.

Exercise is important as adjuvant in the chronic low back pain (CLBP) treatment. Functional training could involve benefits for low back pain (LBP) patients. To evaluate the effects of a 12-week period of functional resistance training on health-related quality of life (HRQOL), disability, body pain, and physical fitness in CLBP females. Nineteen females CLBP were recruited according to Paris Task Force on Back Pain criteria. Participants were randomly assigned to an exercise group (EG); and a control group (CG). Subjects were tested at baseline and at week 12 after 24 sessions, 2 days per week. Body pain was assessed using visual analog scale (VAS), disability with Oswestry Disability Index (ODI) and HRQOL with Short Form 36 questionnaire. Physical fitness was measured using: flamingo test, back endurance test, side bridge test, abdominal curl-up tests, and 60-s squat test. EG showed significant improvements in physical function (10%; p< 0.05), body pain (42%; p< 0.05), vitality (31%; p< 0.05), physical component scale (15%; p< 0.05), VAS (62.5%; p< 0.01), ODI (61.3%; p< 0.05), balance (58%; p< 0.05), curl-up (83%; p< 0.01), squat (22%; p< 0.01), static back (67%; p< 0.01), and side bridge (56%; p< 0.01). Periodized functional resistance training decreased pain and disability and improved HRQOL, balance and physical fitness in females with CLBP, and can thus be used safely in this population.

Enhanced skeletal muscle ribosome biogenesis, yet attenuated mTORC1 and ribosome biogenesis-related signalling, following short-term concurrent versus single-mode resistance training

Combining endurance training with resistance training (RT) may attenuate skeletal muscle hypertrophic adaptation versus RT alone; however, the underlying mechanisms are unclear. We investigated changes in markers of ribosome biogenesis, a process linked with skeletal muscle hypertrophy, following concurrent training versus RT alone. Twenty-three males underwent eight weeks of RT, either performed alone (RT group, n = 8), or combined with either high-intensity interval training (HIT+RT group, n = 8), or moderate-intensity continuous training (MICT+RT group, n = 7). Muscle samples (vastus lateralis) were obtained before training, and immediately before, 1 h and 3 h after the final training session. Training-induced changes in basal expression of the 45S ribosomal RNA (rRNA) precursor (45S pre-rRNA), and 5.8S and 28S mature rRNAs, were greater with concurrent training versus RT. However, during the final training session, RT further increased both mTORC1 (p70S6K1 and rps6 phosphorylation) and 45S pre-rRNA transcription-related signalling (TIF-1A and UBF phosphorylation) versus concurrent training. These data suggest that when performed in a training-accustomed state, RT induces further increases mTORC1 and ribosome biogenesis-related signalling in human skeletal muscle versus concurrent training; however, changes in ribosome biogenesis markers were more favourable following a period of short-term concurrent training versus RT performed alone.

Resistance training and hormone replacement increase MMP-2 activity, quality and quantity of bone in ovariectomized rats

Abstract AIMS The aim of the present study was to investigate the influence of resistance training (RT) and hormone replacement (HR) on MMP-2 activity, biomechanical and physical properties bone of ovariectomized (OVX) rats. METHODS Sprague-Dawley female rats were grouped into six experimental groups (n = 11 per group): sham-operated sedentary (SHAM Sed), ovariectomized sedentary (OVX Sed), sham-operated resistance training (SHAM RT), ovariectomized resistance training (OVX RT), ovariectomized sedentary hormone replacement (OVX Sed-HR), and ovariectomized resistance training hormone replacement (OVX RT-HR). HR groups received implanted silastic capsules with a 5% solution of 17β-estradiol (50 mg 17β-estradiol/ml of sunflower oil). In a 12-week RT period (27 sessions; 4-9 climbs) the animals climbed a 1.1 m vertical ladder with weights attached to their tails. Biomechanical and physical bone analyses were performed using a universal testing machine, and MMP-2 activity analysis was done by zymography. RESULTS Bone density and bone mineral content was higher in the RT and HR groups. The MMP-2 activity was higher in the RT and HR groups. The biomechanical analysis (stiffness, fracture load and maximum load) demonstrated better bone tissue quality in the RT associated with HR. CONCLUSION The RT alone as well as when it is associated with HR was efficient in increasing MMP-2 activity, biomechanical and biophysical properties bone of ovariectomized rats.

Functional capacity improves in-line with neuromuscular performance after 12weeks of non-linear periodization strength training in the elderly.

While it is accepted that resistance training can improve functional capacity in older individuals, the neuromuscular source of this improvement has yet to be identified. This study investigated the link between improved neuromuscular performance and functional capacity after a 12-week resistance training period in untrained healthy older individuals. Fifteen older men and women (60-71years) adhered to a 4-week control period, followed by 12weeks of non-linear resistance training for the lower limbs. Maximum dynamic leg press strength (1-RM), maximum isometric knee extension torque and rate of torque development (RTD) were evaluated at -4, 0, 4, 8, and 12weeks, and muscle activity was assessed at 0, 4, 8, and 12weeks. Functional capacity tests (chair rise, stair ascent and descent, and timed up and go) were performed at -4, 0, and 12weeks. No changes occurred during the control period, but the group increased their 1-RM strength (from 142 ± 53 to 198 ± 43kg, p = 0.001), which was accompanied by an increase in vastus lateralis activation (p = 0.008) during the intervention. Increase was observed at all RTD time intervals at week 8 (p < 0.05). Significant improvements in all the functional capacity tests were observed at week 12 (p < 0.05). Despite the expected increase in strength, RTD, muscle activity, and functional capacity, there was no significant relationship between the changes in neuromuscular performance and functional capacity. While resistance training elicits various positive improvements in healthy older individuals, actual strength gain did not influence the gain in functional capacity. The present study highlights the exact cause that improved the functional capabilities during resistance training are currently unknown.

The effects of resistance training volume on osteosarcopenic obesity in older women

ABSTRACT The aim of this study was to analyze the effects of resistance training (RT) performed with 1 or 3 sets per exercise on osteosarcopenic obesity (OSO) syndrome parameters in older women. Sixty-two older women (68.0 ± 4.3 years, 26.8 ± 4.4 kg/m2) participated in a 12-week RT program. Participants were randomly assigned into one of the three groups: two training groups that performed either 1 set (G1S, n = 21) or 3 sets (G3S, n = 20) 3 times weekly, or a control group (CG, n = 21). Body composition was assessed by dual X-ray absorptiometry, strength was evaluated by 1 repetition maximum testing. The G3S presented significantly higher strength changes than G1S. The changes for percentage of body fat were higher for G3S compared to G1S. There was no difference in skeletal muscle mass between G3S and G1S, however both training groups displayed greater increases in this outcome compared to CG. There was no effect for bone mineral density. The overall analysis indicated higher (P < 0.05) positive changes for G3S than G1S (composed Z-score: G3S = 0.62 ± 0.40; G1S = 0.11 ± 0.48). The results suggest that a 12-week RT period is effective to improve the risk factors of OSO, and that 3 sets induce higher improvements than a single set.

Resistance training and exercise tolerance during high-intensity exercise: moving beyond just running economy and muscle strength.

Resistance training and exercise tolerance during high-intensity exercise: moving beyond just running economy and muscle strength.

Divergent effects of resistance training and anabolic steroid on the postsynaptic region of different skeletal muscles of aged rats

This study aimed to analyze the effects of resistance training associated with testosterone administration in the neuromuscular junction (NMJ) postsynaptic region of different skeletal muscle types of aged rats. Wistar rats were divided into: SEI – 20-months-old control, SEF – 24-months-old control, T – 20-months-old with testosterone, S – 20-months-old resistance trained and ST – 20-months-old with resistance training associated with testosterone propionate. All groups were submitted to familiarization and maximum load carrying testing (MLCT). The MLCT was applied before and after the resistance training (RT) period. RT (6–8×/session with progressive loads of 50 to 100%, 3×/week and 120s interval) was performed in ladder climbing for 15weeks. The administration of testosterone propionate was performed 2×/week (10mg/kg/body weight). After euthanize, soleus and plantaris muscles were removed and prepared for histochemistry and cytofluorescence. T, S and ST significantly increased their maximum carrying load capacity compared to SEI and SEF (p<0.05). For soleus postsynaptic region, ST had lower total and stained area than SEF (p<0.05). For plantaris, the postsynaptic component of T was statistically larger than SEI (p<0.05). For soleus histochemistry, T, S and ST groups showed the same magnitude of type I myofibers hypertrophy, thus statistically different from SEI and SEF (p<0.05). The cross-sectional area of the type IIa myofibers of the ST was larger than SEF (p<0.05). The volume density of type I myofibers show to be lower in ST than SEI (p<0.05). As for type IIa myofibers, ST increased Vv [type IIa] compared to SEI and SEF (p<0.05). For plantaris, T significantly hypertrophied type I myofibers compared to SEI and SEF (p<0.05). S and ST demonstrated significant increases of type I myofibers compared to SEI and SEF (p<0.05). As for type IIx myofibers, both S and ST showed myofibers larger than SEI (p<0.05). However, only the ST had significant difference compared to SEF (p<0.05). In conclusion, both therapies, alone or combined, have little effect on the morphology of the NMJ postsynaptic region of distinct muscles. Moreover, the three therapies are potentially stimulating for strength gains and muscle hypertrophy.

Resistance training improves aortic structure in Wistar rats

BackgroundLittle information is available on the effects of resistance training on the aortic wall. ObjectiveThis study aimed to quantify the effects of a resistance-training program on blood pressure and aortic wall structural components. MethodsRats (aged three months) were randomized into sedentary group (control group, CG; n=10) or trained group (TG; n=10). The TG rats performed resistance training by climbing a 1.1-m vertical ladder (80° incline) five times a week for 12 weeks, and the CG remained sedentary. The rats were sacrificed and 5mm of the ascending aorta was submitted to histological sections, which were stained with hematoxylin–eosin, Picrosirius red, and Verhoeff's elastin, and used for morphometric studies. Left ventricle (LV) hypertrophy was determined by measuring LV wall thickness and LV internal diameter. ResultsThe rats had similar repetition maximum before the resistance training. At the end of the resistance training period, the repetition maximum of the TG was 3.04-fold greater than the body weight. In the twelfth month, the left ventricular weight was 15.3% larger in the TG than in the CG, and the left ventricular internal diameter was reduced by 10% in the TG. Rats exposed to resistance training had a significant increase in aortic wall thickness, in both elastic lamina and collagen fibers, and in the thickness of collagen fibrils. ConclusionResistance training induces the development of concentric cardiac hypertrophy and improves the aortic wall components by producing a morphological expression pattern distinct from aortic pathological adaptation.

Resistance training prescription with different load-management methods improves phase angle in older women

The purpose of the present study was to investigate the effect of two different resistance training (RT) prescription methods on phase angle (PA) in older women. Seventy-six older women (68.5 ± 5.7 years) were randomly assigned to one of three groups: two training groups that performed an eight-week RT programme either in a constant load (CT, n = 25) or an ascending pyramidal load (PR, n = 26) routine three times per week, or a control group (CG, n = 25) that performed no exercise. The CT programme consisted of three sets of 8–12 repetition maximum (RM) with a constant load for the three sets, whereas the PR training consisted of three sets of 12/10/8 RM with incremental loads for each set. PA was assessed by whole-body spectral bioelectrical impedance. After the RT period, both CT and PR achieved higher (P < .05) values of PA (CT = 5.76 ± 0.59°, PR = 5.63 ± 0.61°, CG = 5.48 ± 0.46°) compared to the CG; however, there was no difference (P > .05) between trained groups. The results suggest that eight weeks of RT based on a PR and CT load routines promote an improvement in PA, and both prescription methods performed similarly.

Ribosome biogenesis is activated during the early period of resistance training in rat skeletal muscle

Resistance training (RT) induces skeletal muscle hypertrophy. Recently, it has been suggested that ribosome biogenesis plays an important part in RT‐induced skeletal muscle hypertrophy. However, influence of number of RT bouts is unclear.PurposeThe present study aimed to investigate the change of ribosomal RNA (rRNA) and ribosome protein content with changing the number of RT bouts.MethodMale Sprague‐Dawley rats were randomly assigned into six groups: Control (Cont), resistance‐trained with 1bout (1B), 2bouts (2B), 3bouts (3B), 6bouts (6B) and 18bouts(18B). RT protocol consisted of 50 repetitions of maximal isometric contraction of the gastrocnemius muscle by direct electric stimulation. Groups other than 1B performed 3 bouts of training per week. Muscle samples were collected 3h, 6h and 48h after the final exercise session in 1B to 3B, and 48h after the final exercise session in 6B and 18B.ResultsThe content of 18S+28S rRNA and rpS6 increased in 1B to 3B, but no significant difference was seen between 3B, 6B and 18B.ConclusionThe present showed that ribosome biogenesis is activated during the early period of RT. These results suggested that activation of ribosome biogenesis may contribute to increase protein synthesis during the later period, thereby leading to muscle hypertrophy.

Effect of protein quality on recovery after intense resistance training.

The present study investigated the effects of high- versus low-quality protein supplementation on the regain of exercise performance during recovery from a period of high-intensity resistance training. In a diet-controlled crossover study, 12 resistance-trained participants performed two identical training periods, with each training period including four sessions of high-intensity resistance exercise during 5days, while receiving either high- or low-quality protein. Prior to and at 3, 24 and 48h after the training periods, performance was evaluated in knee extensor and flexor isometric maximal voluntary contraction (MVC), counter-movement jumping height (CMJ), and peak and mean anaerobic power. In addition, prior to and at 48h after the training periods, performance in time-to-exhaustion at 70% of VO2max (TTE) was evaluated. After the intense training periods, decrements in the order of 4-24% were observed for MVCext, CMJ, mean anaerobic power, and TTE. In particular for TTE, this decrement in exercise performance did not attain full recovery at 48h post-exercise. The regain of exercise performance was not dictated by type of protein supplement. The regain of muscle strength as well as anaerobic or aerobic performances were not markedly influenced by the type of protein supplement.

Effect Of Training Frequency On Muscle Mass, Strength And Power Performance During Reduced Resistance Training

Reduced resistance training (RRT) has been suggested to maintain muscular adaptations (e.g. muscle hypertrophy, muscle strength power). The RRT may be applied after a period of high intensity resistance training (HIRT) by reducing training volume and changing frequency. Several studies have shown positive RRT effects when training volume is decreased 50-60%. However, the effects of different training frequencies during RRT on muscle mass, muscle strength and power performance remain unknown. PURPOSE: To investigate the effect of different training frequencies on muscle mass, strength and power performance during a period of RRT. METHODS: Thirty three physically active male subjects were submitted to 8 weeks of upper limbs high intensity resistance training (HIRT) divided into two 4-wk periods (i.e. 2.d.wk−1 the first 4 wk and 3.d.wk−1 the last 4 wks). After that they randomly assigned to three experimental groups: reduced resistance training 2 (RRT2 = two sessions per week), reduced resistance training 1 (RRT1 = one session per week), and detraining (DT = interrupted training). RRT1 and RRT2 reduced training session volume by 50-55% and DT group detrained for 8 more weeks. Triceps brachii cross sectional area (TCSA), maximal dynamic strength (1RM), and muscle power (PPw) in the bench press exercise were measured before, after RT, and after RRT. RESULTS: RRT1, RRT2, and DT showed similar increases in the TCSA after the HIRT period [16.5% (±3.6), 15.9% (±2.7), and 17.1% (±4.6) (p<0.01), respectively]. The 1RM and PPw also increased similarly for all three groups [17.2% (±2.9), 41.1% (±6.4), and 41.8% (±5.1) and 15.8% (±6.4), 15.3% (±5.4), and 18.2% (±7.3), respectively]. After the RRT period, RRT1 and RRT2 groups were able to maintain their TCSA, 1RM and PPw performance while DT showed significant decreases in TCSA (13.1±4.2%), 1RM (23.7±6.8%), and PPw (15.7±5.3%). CONCLUSION: The results showed that RRT performed once or twice a week but with similar training volume is able to maintain muscle hypertrophy, strength and power performance obtained after 8 weeks of HIRT.

Low-intensity resistance training with blood flow restriction improves vascular endothelial function and peripheral blood circulation in healthy elderly people.

The present study aimed to investigate the effects of low-intensity resistance training with blood flow restriction (BFR resistance training) on vascular endothelial function and peripheral blood circulation. Forty healthy elderly volunteers aged 71 ± 4 years were divided into two training groups. Twenty subjects performed BFR resistance training (BFR group), and the remaining 20 performed ordinary resistance training without BFR. Resistance training was performed at 20 % of each estimated one-repetition maximum for 4 weeks. We measured lactate (Lac), norepinephrine (NE), vascular endothelial growth factor (VEGF) and growth hormone (GH) before and after the initial resistance training. The reactive hyperemia index (RHI), von Willebrand factor (vWF) and transcutaneous oxygen pressure in the foot (Foot-tcPO2) were assessed before and after the 4-week resistance training period. Lac, NE, VEGF and GH increased significantly from 8.2 ± 3.6 mg/dL, 619.5 ± 243.7 pg/mL, 43.3 ± 15.9 pg/mL and 0.9 ± 0.7 ng/mL to 49.2 ± 16.1 mg/dL, 960.2 ± 373.7 pg/mL, 61.6 ± 19.5 pg/mL and 3.1 ± 1.3 ng/mL, respectively, in the BFR group (each P < 0.01). RHI and Foot-tcPO2 increased significantly from 1.8 ± 0.2 and 62.4 ± 5.3 mmHg to 2.1 ± 0.3 and 68.9 ± 5.8 mmHg, respectively, in the BFR group (each P < 0.01). VWF decreased significantly from 175.7 ± 20.3 to 156.3 ± 38.1 % in the BFR group (P < 0.05). BFR resistance training improved vascular endothelial function and peripheral blood circulation in healthy elderly people.

Time Course of Resistance Training–Induced Muscle Hypertrophy in the Elderly

Extended periods of resistance training (RT) induce muscle hypertrophy. Nevertheless, to date, no study has investigated the time window necessary to observe significant changes in muscle cross-sectional area (CSA) in older adults. Therefore, this study investigated the time course of muscle hypertrophy after 10 weeks (20 sessions) of RT in the elderly. Fourteen healthy older subjects were randomly allocated in either the RT (n: 6) or control group (n: 8). The RT was composed of 4 sets × 10 repetitions (70-80% 1 repetition maximum [1RM]) in a leg press machine. The time course of vastus lateralis muscle hypertrophy (CSA) was assessed on a weekly basis by mode-B ultrasonography. Leg press muscle strength was assessed by dynamic 1RM test. Our results demonstrated that the RT group increased leg press 1RM by 42% (p ≤ 0.05) after 10 weeks of training. Significant increases in vastus lateralis muscle CSA were observed only after 18 sessions of training (9 weeks; p ≤ 0.05; 7.1%). In conclusion, our training protocol promoted muscle mass accrual in older subjects, and this was only observable after 18 sessions of RT (9 weeks).

The effects of whey protein with or without carbohydrates on resistance training adaptations.

BackgroundNutrition intake in the context of a resistance training (RT) bout may affect body composition and muscle strength. However, the individual and combined effects of whey protein and carbohydrates on long-term resistance training adaptations are poorly understood.MethodsA four-week preparatory RT period was conducted in previously untrained males to standardize the training background of the subjects. Thereafter, the subjects were randomized into three groups: 30 g of whey proteins (n = 22), isocaloric carbohydrates (maltodextrin, n = 21), or protein + carbohydrates (n = 25). Within these groups, the subjects were further randomized into two whole-body 12-week RT regimens aiming either for muscle hypertrophy and maximal strength or muscle strength, hypertrophy and power. The post-exercise drink was always ingested immediately after the exercise bout, 2–3 times per week depending on the training period. Body composition (by DXA), quadriceps femoris muscle cross-sectional area (by panoramic ultrasound), maximal strength (by dynamic and isometric leg press) and serum lipids as basic markers of cardiovascular health, were analysed before and after the intervention.ResultsTwelve-week RT led to increased fat-free mass, muscle size and strength independent of post-exercise nutrient intake (P < 0.05). However, the whey protein group reduced more total and abdominal area fat when compared to the carbohydrate group independent of the type of RT (P < 0.05). Thus, a larger relative increase (per kg bodyweight) in fat-free mass was observed in the protein vs. carbohydrate group (P < 0.05) without significant differences to the combined group. No systematic effects of the interventions were found for serum lipids. The RT type did not have an effect on the adaptations in response to different supplementation paradigms.ConclusionsPost-exercise supplementation with whey proteins when compared to carbohydrates or combination of proteins and carbohydrates did not have a major effect on muscle size or strength when ingested two to three times a week. However, whey proteins may increase abdominal fat loss and relative fat-free mass adaptations in response to resistance training when compared to fast-acting carbohydrates.

Early resistance training-induced increases in muscle cross-sectional area are concomitant with edema-induced muscle swelling.

It has been proposed that skeletal muscle shows signs of resistance training (RT)-induced muscle hypertrophy much earlier (i.e., ~3-4 weeks of RT) than previously thought. We determined if early increases in whole muscle cross-sectional area (CSA) during a period of RT were concomitant with edematous muscle swelling and thus not completely attributable to hypertrophy. We analyzed vastus lateralis muscle ultrasound CSA images and their respective echo intensities (CSA-USecho) at the beginning (T1), in the 3rd week of RT (T2) and at the end (T3) of a 10-week RT period in ten untrained young men. Functional parameters [training volume (TV = load × reps × sets) and maximal voluntary contraction (MVC)] and muscle damage markers (myoglobin and interleukin-6) were also assessed. Muscle CSA increased significantly at T2 (~2.7%) and T3 (~10.4%) versus T1. Similarly, CSA-USecho increased at T2 (~17.2%) and T3 (~13.7%). However, when CSA-USecho was normalized to the increase in muscle CSA, only T2 showed a significantly higher USecho versus T1. Additionally, TV increased at T2 and T3 versus T1, but MVC increased only at T3. Myoglobin and Interleukin-6 were elevated at T2 versus T1, and myoglobin was also higher at T2 versus T3. We propose that early RT-induced increases in muscle CSA in untrained young individuals are not purely hypertrophy, since there is concomitant edema-induced muscle swelling, probably due to muscle damage, which may account for a large proportion of the increase. Therefore, muscle CSA increases (particularly early in an RT program) should not be labeled as hypertrophy without some concomitant measure of muscle edema/damage.