Effects of a Home-Based Stretching Program on Bench Press Maximum Strength and Shoulder Flexibility.

Recent research showed significant stretch-mediated maximum strength increases when performing stretching between 5 to 120 minutes per day with the calf muscle. However, since the practical applicability of these long stretching durations was questioned and studies exploring the transferability to the upper body are scarce, the aim of this study was to investigate the possibility of using a home-based stretching program to induce significant increases in maximum strength and flexibility. Therefore, 31 recreationally active participants (intervention group: 18, control group: 13) stretched the pectoralis major for 15min/day for eight weeks, incorporating three different stretching exercises. The maximum strength was tested isometrically and dynamically in the bench press (one-repetition maximum: 1RM) as well as shoulder range of motion (ROM) performing bilateral shoulder rotation with a scaled bar. Using a two-way analysis of variance (ANOVA) with repeated measures, the results showed high magnitude Time effects (ƞ² = 0.388-0.582, p < 0.001) and Group*Time interaction (ƞ² = 0.281-0.53, p < 0.001-0.002), with increases of 7.4 ± 5.6% in 1RM and of 9.8 ± 5.0% in ROM test in the intervention group. In the isometric testing, there was a high-magnitude Time effect (ƞ² = 0.271, p = 0.003), however, the Group*Time interaction failed to reach significance (p = 0.75). The results are in line with previous results that showed stretch-mediated maximum strength increases in the lower extremity. Future research should address the underlying physiological mechanisms such as muscle hypertrophy, contraction conditions as well as pointing out the relevance of intensity, training frequency and stretching duration.

Relationship between hypertrophy, strength gains and tensiomyography adaptations: a moderator role of contraction duration.

The aim of the study was to investigate how the relationship between resistance training-induced hypertrophy, strength, and passive contractile adaptations is affected by contraction duration. Twenty university students (11 males) were randomly assigned to either the fast eccentric/fast concentric phase group (F/F; 1 s both phases) or the slow eccentric/fast concentric phase group (S/F; 4 s and 1 s, respectively). Both experimental groups completed a 7-week biceps curl training programme with a total of 14 sessions (2 days/week). Elbow flexor muscle thickness (MT), one-repetition maximum (1RM), and tensiomyographic (TMG) parameters (radial displacement-Dm and contraction time-Tc) were assessed. The percentage change (∆) in MT correlated significantly with the ∆1RM only in the S/F group (r = 0.712, p < 0.05). Both groups demonstrated significant negative associations between ∆MT and ∆Dm (r = 0.717-0.760, p < 0.01). Conversely, no significance was found between ∆MT and ∆Tc (F/F: r = -0.398, p = 0.255; S/F: r = 0.410, p = 0.239), ∆1RM and ∆Tc (F/F: r = -0.278, p = 0.436; S/F: r = 0.223, p = 0.536), nor ∆1RM and ∆Dm (F/F: r = - 0.131, p = 0.719; S/F: r = - 0.351, p = 0.320). The main findings indicate that the relationship between hypertrophy and strength gains is significantly stronger when resistance training was paced with slower eccentric contractions comparing to fast ones. On the other hand, reduced Dm values indicate increase in MT regardless of contraction duration, while strength gains are not correlated with corresponding TMG changes.

Estimation of 1-Repetition Maximum Using a Hydraulic Bench Press Machine Based on User's Lifting Speed and Load Weight.

1-repetition maximum (1RM), a representative index for an individual's weightlifting capacity, provides an organized workout guide, but to measure 1RM needs several repetitive exercises up to one's limit and has a risk of injury, thus, not adequate for beginners, elders, or disabled people. This study suggests a simpler and safer 1RM measurement method using a hydraulic fitness machine. We asked twenty-five female subjects with less than a month of experience in weight training to repeat chest exercises using a conventional plate-loaded bench press machine and a hydraulic bench press machine and measured 1RMs. Repeated-measures ANOVA and paired t-test reported the difference between the plate and hydraulic 1RMs insignificant (p-value = 0.082) and confirmed the generality of 1RM across the different types of fitness machines. We then derived several 1RM equations in terms of load weight W and lifting speed v during non-1RM exercise and reduced it to a first-order polynomial expression 1RM=-0.3908+0.8251W+0.1054v with adjusted R-square of 0.8849. Goodness-of-fit test and comparison with 1RM equations from reference studies (v=-1.46×W1RM+1.7035, W1RM×100=7.5786v2-75.865v+113.02) verified our formula valid. We finally simplified the 1RM measurement process up to a maximum of three repetitions.

Supervised high-load resistance training for improving muscle strength and quality in prediabetic older adults: A pilot randomized controlled trial.

OBJECTIVE: To investigate the effects of high- and low-load supervised, volume-matched resistance training (RT) on body composition, muscle function, and functional capacity in older adults with prediabetes. METHODS: Older adults with prediabetes were recruited and randomly assigned to high-load RT (n = 13), low-load RT (n = 12), or control groups (n = 12). RESULTS: No significant differences were observed in body composition at postintervention. High-load and low-load RT groups exhibited significant improvements in functional tests at postintervention compared with the control group. The high-load RT group exhibited a greater improvement in muscle strength and muscle quality at postintervention compared with the low-load RT group. CONCLUSION: Supervised RT is useful in the prevention of muscle functional loss in older adults with prediabetes. High-load RT is superior for enhancing muscle strength and muscle quality, despite a similar increase in functional capacity.

Reliability of Isometric Muscle Strength Measurement and Its Accuracy Prediction of Maximal Dynamic Force in People with Multiple Sclerosis.

Background and Objectives: Multiple sclerosis (MS) is a disease that manifests with varied neurological symptoms, including muscle weakness, especially in the lower extremities. Strength exercises play an important role in the rehabilitation and functional maintenance of these patients. The individualized prescription of strength exercises is recommended to be based on the maximum force determined by the one-repetition maximum (1RM), although to save time and because it requires less equipment, it is often determined by the maximum voluntary isometric contraction (MVIC). The purpose of this work was to study, in patients with MS (pwMS), the reliability of MVIC and the correlation between the MVIC and 1RM of the knee extensors and to predict the MVIC-based 1RM. Materials and Methods: A total of 328 pwMS participated. The study of the reliability of MVIC included all pwMS, for which MVIC was determined twice in one session. Their 1RM was also evaluated. The sample was randomized by MS type, sex, and neurological disability score into a training group and a testing group for the analysis of the correlation and prediction of MVIC-based 1RM. Results: MVIC repeatability (ICC, 2.1 = 0.973) was determined, along with a minimum detectable change of 13.2 kg. The correlation between MVIC and 1RM was R2 = 0.804, with a standard error estimate of 12.2 kg. The absolute percentage error of 1RM prediction based on MVIC in the test group was 12.7%, independent of MS type and with no correlation with neurological disability score. Conclusions: In patients with MS, MVIC presents very good intrasubject repeatability, and the difference between two measurements of the same subject must differ by 17% to be considered a true change in MVIC. There is a high correlation between MVIC and 1RM, which allows estimation of 1RM once MVIC is known, with an estimation error of about 12%, regardless of sex or type of MS, and regardless of the degree of neurological disability.

Effects of resistance training on hypertrophy, strength and tensiomyography parameters of elbow flexors: role of eccentric phase duration.

The aim of the study was to compare the effects of two different training protocols, which differ in the duration of the eccentric phase, on the one-repetition maximum (1RM), thickness and contractile properties of elbow flexors. Twenty untrained college students were randomly divided into two experimental groups, based on the training tempo: FEG (Faster Eccentric Group: 1/0/1/0) and SEG (Slower Eccentric Group: 4/0/1/0). Training intervention was a biceps bending exercise, conducted twice a week for 7 weeks. The intensity (60-70% RM), sets (3-4) and rest intervals (120 s) were held constant, while repetitions were performed until it was not possible to maintain a set duration. In the initial and final measurements, 1RM, muscle thickness and tensiomyography parameters - contraction time (Tc) and radial deformation (Dm) - were evaluated. An ANCOVA model (using baseline outcomes as covariates) was applied to determine between-group differences at post-test, while Pearson's product-moment correlation coefficient was used to investigate the relationship between absolute changes in muscle thickness and Dm. Muscle strength increase was greater for SEG than for FEG (6.0 ± 1.76 vs. 3.30 ± 2.26 kg, p < 0.01). In both groups muscle thickness increased equally (FEG: 3.24 ± 2.01 vs. SEG: 3.57 ± 1.17 mm, p < 0.01), while an overall reduction in Dm was observed (FEG: 1.99 ± 1.20 vs. SEG: 2.26 ± 1.03 mm, p < 0.01). Values of Tc remained unchanged. A significant negative relationship was observed between changes in muscle thickness and Dm (r = -0.763, Adj.R² = 0.560, p < 0.01). These results indicate that the duration of the eccentric phase has no effect on muscle hypertrophy in untrained subjects, but that slower eccentric movement significantly increases 1RM.

Resistance training induced changes in strength and specific force at the fiber and whole muscle level: a meta-analysis.

PURPOSE: Considerable debate exists as to whether increases in strength that occur with resistance exercise are the result of increases in muscle size. Most studies have attempted to answer this question using assessments of whole muscle size and voluntary muscle strength, but examining changes at the individual muscle fiber level may also provide some insight. The purpose of this meta-analysis was to compare adaptations at the whole muscle and individual fiber level. METHODS: A meta-analysis was conducted in February, 2018 including all previously published papers and was analyzed using a random effects model. RESULTS: There were no differences (p = 0.88) when comparing hypertrophy at the whole muscle (4.6%) and individual fiber level (7.0%), but significantly larger (p < 0.001) strength gains were observed at the whole muscle level (43.3%) relative to the individual fiber (19.5%). Additionally, there was an increase in the specific tension of type 1 muscle fibers (p = 0.013), but not type 2 muscle fibers (p = 0.23) which was driven by similar increases in strength (type 1: 17.5%, type 2A: 17.7%), despite differences in muscle size (type 1: 6.7%, type 2A: 12.1%). CONCLUSION: These results support the hypothesis that the neural adaptations play a large role in increasing isotonic whole muscle strength, but also demonstrate that an improvement in specific tension of type 1 muscle fibers is present. These results would suggest that some mechanism intrinsic to the muscle fiber, and independent of muscle growth, may also be contributing to strength increases in response to resistance exercise providing an avenue for future research.

Timing of post-resistance exercise nutrient ingestion: effects on gastric emptying and glucose and amino acid responses in humans.

This study examined the effects of post-resistance exercise protein ingestion timing on the rate of gastric emptying (GE) and blood glucose (BG) and plasma branched-chain amino acid (BCAA) responses. In all, eleven healthy participants randomly ingested 400 ml of a nutrient-rich drink containing 12 g carbohydrates and 20 g protein at rest (Con), at 5 min (post-exercise (PE)-5) or at 30 min (PE-30) after a single bout of strenuous resistance exercises. The first and second sets comprised ten repetitions at 50 % of each participant's one-repetition maximum (1RM). The third, fourth and fifth sets comprised ten repetitions at 75 % of 1RM, and the sixth set involved repeated repetitions until exhaustion. Following ingestion of the nutrient-rich drink, we assessed the GE rate using 13C-sodium acetate breath test and evaluated two parameters according to the T max-calc (time when the recovery per hour is maximised), which is a standard analytical method, and T 1/2 (time when the total cumulative dose of [13CO2] reaches one-half). T max-calc and T 1/2 were slower for the PE-5 condition than for either the PE-30 or Con condition (T max-calc; Con: 53 (sd 7) min, PE-5: 83 (sd 16) min, PE-30: 62 (sd 9) min, T 1/2; Con: 91 (sd 7) min, PE-5: 113 (sd 21) min, PE-30: 91 (sd 11) min, P<0·05). BG and BCAA responses were also slower for the PE-5 condition than for either the PE-30 or Con condition. Ingesting nutrients immediately after strenuous resistance exercise acutely delayed GE, which affected BG and plasma BCAA levels in blood circulation.

Moderately heavy exercise produces lower cardiovascular, RPE, and discomfort compared to lower load exercise with and without blood flow restriction.

PURPOSE: To determine the acute cardiovascular and perceptual responses of low-load exercise with or without blood flow restriction and compare those responses to that of moderately heavy exercise. METHODS: Twenty-two participants completed unilateral elbow flexion exercise with a moderately heavy-load- [70% one-repetition maximum (1RM); 70/0] and with three low-load conditions (15% 1RM) in combination with 0% (15/0), 40%, (15/40) and 80% (15/80) arterial occlusion pressure. Participants exercised until failure (or until 90 repetitions per set). The cardiovascular response (arterial occlusion) was measured pre and post exercise and the perceptual responses [ratings of perceived exertion (RPE) and discomfort] were determined before and after each set of exercise. RESULTS: For arterial occlusion pressure, the lower-load conditions had greater change from pre to post compared to 70/00 (e.g., 15/80: 44 vs. 70/0: 34 mmHg). RPE was highest across the sets for the 15/80 condition with the other conditions having similar RPE (e.g., set 4: median rating of 17.2 for 15/80 vs. ~ 15.5 for other conditions). Ratings of discomfort were also greatest for the 15/80 condition (15/80 > 15/40 > 15/0 > 70/0). Exercise volume within the 15/0 and 15/40 conditions were similar but were significantly greater than that observed with the 15/80 and 70/0 conditions. CONCLUSION: Low-load exercise to volitional failure results in a greater cardiovascular response to that of moderately heavy-load exercise. When high pressure is applied to low load exercise, there is a reduction in exercise volume but an elevated perceptual response that may be an important consideration when applying this stimulus in practice.

What does individual strength say about resistance training status?

The point at which an individual becomes resistance "trained" is not well defined in the literature. Some studies have defined training status as having engaged in consistent resistance training activities for a given period of time, whereas others base inclusion criteria on strength levels alone, or levels of strength in combination with training age/time. If the primary focus of a study is to examine adaptations in individuals with high levels of strength, then it may be appropriate to exclude the individuals who do not meet strength requirements. However, given the heterogeneity of the strength response to resistance training, strength cannot separate those who are "trained" from those who are "untrained." We suggest that, when determining resistance training status, training age (time) and the modality of training (specificity) should be the primary criteria considered. Muscle Nerve 55: 455-457, 2017.

Muscle growth: To infinity and beyond?

Strength increases following training are thought to be influenced first by neural adaptions and second by large contributions from muscle growth. This is based largely on the idea that muscle growth is a slow process and that a plateau in muscle growth would substantially hinder long-term increases in strength. This Review examines the literature to determine the time course of skeletal muscle growth in the upper and lower body and to determine whether and when muscle growth plateaus. Studies were included if they had at least 3 muscle size time points, involved participants 18 years or older, and used a resistance training protocol. Muscle growth occurs sooner than had once been hypothesized, and this adaptation is specific to the muscle group. Furthermore, the available studies indicate that the muscle growth response will plateau, and additional growth is not likely to occur appreciably beyond this initial plateau. However, the current study durations are a limitation. Muscle Nerve 56: 1022-1030, 2017.

Estimation of 1RM for knee extension based on the maximal isometric muscle strength and body composition.

[Purpose] To create a regression formula in order to estimate 1RM for knee extensors, based on the maximal isometric muscle strength measured using a hand-held dynamometer and data regarding the body composition. [Subjects and Methods] Measurement was performed in 21 healthy males in their twenties to thirties. Single regression analysis was performed, with measurement values representing 1RM and the maximal isometric muscle strength as dependent and independent variables, respectively. Furthermore, multiple regression analysis was performed, with data regarding the body composition incorporated as another independent variable, in addition to the maximal isometric muscle strength. [Results] Through single regression analysis with the maximal isometric muscle strength as an independent variable, the following regression formula was created: 1RM (kg)=0.714 + 0.783 × maximal isometric muscle strength (kgf). On multiple regression analysis, only the total muscle mass was extracted. [Conclusion] A highly accurate regression formula to estimate 1RM was created based on both the maximal isometric muscle strength and body composition. Using a hand-held dynamometer and body composition analyzer, it was possible to measure these items in a short time, and obtain clinically useful results.

Sensing Positive versus Negative Reward Signals through Adenylyl Cyclase-Coupled GPCRs in Direct and Indirect Pathway Striatal Medium Spiny Neurons.

Transient changes in striatal dopamine (DA) concentration are considered to encode a reward prediction error (RPE) in reinforcement learning tasks. Often, a phasic DA change occurs concomitantly with a dip in striatal acetylcholine (ACh), whereas other neuromodulators, such as adenosine (Adn), change slowly. There are abundant adenylyl cyclase (AC) coupled GPCRs for these neuromodulators in striatal medium spiny neurons (MSNs), which play important roles in plasticity. However, little is known about the interaction between these neuromodulators via GPCRs. The interaction between these transient neuromodulator changes and the effect on cAMP/PKA signaling via Golf- and Gi/o-coupled GPCR are studied here using quantitative kinetic modeling. The simulations suggest that, under basal conditions, cAMP/PKA signaling could be significantly inhibited in D1R+ MSNs via ACh/M4R/Gi/o and an ACh dip is required to gate a subset of D1R/Golf-dependent PKA activation. Furthermore, the interaction between ACh dip and DA peak, via D1R and M4R, is synergistic. In a similar fashion, PKA signaling in D2+ MSNs is under basal inhibition via D2R/Gi/o and a DA dip leads to a PKA increase by disinhibiting A2aR/Golf, but D2+ MSNs could also respond to the DA peak via other intracellular pathways. This study highlights the similarity between the two types of MSNs in terms of high basal AC inhibition by Gi/o and the importance of interactions between Gi/o and Golf signaling, but at the same time predicts differences between them with regard to the sign of RPE responsible for PKA activation. SIGNIFICANCE STATEMENT: Dopamine transients are considered to carry reward-related signal in reinforcement learning. An increase in dopamine concentration is associated with an unexpected reward or salient stimuli, whereas a decrease is produced by omission of an expected reward. Often dopamine transients are accompanied by other neuromodulatory signals, such as acetylcholine and adenosine. We highlight the importance of interaction between acetylcholine, dopamine, and adenosine signals via adenylyl-cyclase coupled GPCRs in shaping the dopamine-dependent cAMP/PKA signaling in striatal neurons. Specifically, a dopamine peak and an acetylcholine dip must interact, via D1 and M4 receptor, and a dopamine dip must interact with adenosine tone, via D2 and A2a receptor, in direct and indirect pathway neurons, respectively, to have any significant downstream PKA activation.

Carbohydrate intake and resistance-based exercise: are current recommendations reflective of actual need?

Substantial research has been completed examining the impact of carbohydrate (CHO) intake on endurance exercise, whereas its role in resistance-based exercise performance, adaptation and cell signalling has yet to be fully characterised. This empirical shortcoming has precluded the ability to establish specific CHO recommendations for resistance exercise. This results in recommendations largely stemming from findings based on endurance exercise and/or anecdotal evidence despite the distinct energetic demands and molecular responses mediating adaptation from endurance- and resistance-based exercise. Moreover, the topic of CHO and exercise has become one of polarising nature with divergent views - some substantiated, others lacking evidence. Current literature suggests a moderately high daily CHO intake (3-7 g/kg per d) for resistance training, which is thought to prevent glycogen depletion and facilitate performance and adaptation. However, contemporary investigation, along with an emerging understanding of the molecular underpinnings of resistance exercise adaptation, may suggest that such an intake may not be necessary. In addition to the low likelihood of true glycogen depletion occurring in response to resistance exercise, a diet restrictive in CHO may not be detrimental to acute resistance exercise performance or the cellular signalling activity responsible for adaptation, even when muscle glycogen stores are reduced. Current evidence suggests that signalling of the mammalian target of rapamycin complex 1, the key regulatory kinase for gene translation (protein synthesis), is unaffected by CHO restriction or low muscular glycogen concentrations. Such findings may call into question the current view and subsequent recommendations of CHO intake with regard to resistance-based exercise.

Football training improves lean body mass in men with prostate cancer undergoing androgen deprivation therapy.

Androgen deprivation therapy (ADT) remains a cornerstone in the management of patients with prostate cancer (PCa) despite adverse effects on body composition and functional parameters. We compared the effects of football training with standard care in PCa patients managed with ADT (> 6 months). Fifty-seven men aged 67 (range: 43-74) were randomly assigned to a football group (FG, n = 29) or a usual care control group (CON, n = 28). The primary outcome was change in lean body mass (LBM) assessed by dual-energy X-ray absorptiometry scanning. Secondary outcomes included changes in knee-extensor muscle strength (one repetition maximum), fat percentage, and maximal oxygen uptake (VO2max ). Mean heart rate during training was 137.7 (standard deviation 13.7) bpm or 84.6 (3.9)% HRmax. In FG, LBM increased by 0.5 kg [95% confidence interval (CI) 0.1-0.9; P = 0.02] with no change in CON (mean group difference 0.7 kg; 95% CI 0.1-1.2; P = 0.02). Also, muscle strength increased in FG (8.9 kg; 95% CI 6.0-11.8; P < 0.001) with no change in CON (mean group difference 6.7 kg; 95% CI 2.8-10.7; P < 0.001). In FG, VO2max increased (1.0 mL/kg/min; 95% CI 0.2-1.9; P = 0.02) and fat percentage tended to decrease (0.7%; 95%CI 1.3-0.0; P = 0.06), but these changes were not significantly different from CON. In conclusion, football training over 12 weeks improved LBM and muscle strength compared with usual care in men with prostate cancer receiving ADT.

A botanical extract blend of Mangifera indica and Sphaeranthus indicus combined with resistance exercise training improves muscle strength and endurance over exercise alone in young men: a randomized, blinded, placebo-controlled trial.

Resistance exercise training (RET) is used to improve muscular strength and function. This study tested the hypothesis that RET alongside daily supplementation of a Sphaeranthus indicus and Mangifera indica extract blend (SMI) would augment bench press (BP) and leg extension (LE) strength and repetitions to failure (RTF) compared to RET alone. Ninety-nine men (age 22 ± 3) completed the trial after randomization into one of four groups: (A1) 425 mg SMI plus one RET set; (A2) 850 mg SMI plus one RET set; (P1) placebo plus one RET set; and (P2) placebo plus two RET sets. RET sets were 6-8 BP and LE repetitions at 80% of a progressive one repetition maximum (1-RM), performed 3x/week for 8 weeks. Strength and RTF were evaluated at baseline and days 14, 28, and 56 while serum values of total testosterone (TT), free testosterone (FT), and cortisol (C) values were evaluated at baseline and day 56. RET significantly (p < 0.05) increased 1-RM, RTF, and T measures above baselines regardless of group assignment, but the increases were greater in the supplemented groups. At week 8, A1 bench pressed more than P1 (71.5.5 ± 17.5 kg vs. 62.0 ± 15.3 kg, p = 0.003), while A2 pressed 13.8 ± 3.0 kg more (95% CI 5.7-21.8, p < 0.001) than P1 and 9.9 ± 13.0 kg more (95% CI 1.7-18.2, p = 0.01) than P2. Also at week 8, the mean LE 1-RM of A1 (159.4 ± 22.6 kg) and A2 (162.2 ± 22.9 kg) was greater (p < 0.05) than that of P1 (142.2 ± 25.6 kg) and P2 (146.5 ± 19.7 kg). Supplementation improved RTF, TT, and FT values over those measured in exercise alone (p < 0.05), while C levels in A2 (9.3 ± 3.8 µg/dL) were lower than P2 (11.7 ± 3.8 µg/dL, p < 0.05). Daily supplementation with SMI was well tolerated and may help optimize muscle adaptive responses to RET in men.

Which neuromuscular attributes are most associated with mobility among older primary care patients?

OBJECTIVE: To identify the neuromuscular attributes that are associated with self-reported mobility status among older primary care patients. DESIGN: Cohort study. SETTING: Metropolitan-based health care system. PARTICIPANTS: Community-dwelling primary care patients aged ≥65 years (N=430), with self-reported modification of mobility tasks resulting from underlying health conditions. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Basic and Advanced Lower Extremity Function as measured by the Late Life Function and Disability Instrument. RESULTS: We constructed multivariable linear regression models evaluating both outcomes. For Basic Lower Extremity Function, leg strength, leg velocity, trunk extensor muscle endurance, and ankle range of motion (ROM) were statistically significant predictors (P<.001, R(2)=.21). For Advanced Lower Extremity Function, leg strength, leg strength asymmetry, leg velocity, trunk extensor muscle endurance, and knee flexion ROM were statistically significant predictors (P<.001, R(2)=.39). Sensitivity analyses conducted using multiple imputations to account for missing data confirmed these findings. CONCLUSIONS: This analysis highlights the relevance and importance of 5 categories of neuromuscular attributes: strength, speed of movement, ROM, asymmetry, and trunk stability. It identifies novel attributes (leg velocity and trunk extensor muscle endurance) relevant to mobility and highlights that impairment profiles vary by the level of mobility assessed. These findings will inform the design of more thorough and potentially more effective disability prevention strategies.

Systematic review of high-intensity progressive resistance strength training of the lower limb compared with other intensities of strength training in older adults.

OBJECTIVE: To examine the effect of high-intensity progressive resistance strength training (HIPRST) on strength, function, mood, quality of life, and adverse events compared with other intensities in older adults. DATA SOURCES: Online databases were searched from their inception to July 2012. STUDY SELECTION: Randomized controlled trials of HIPRST of the lower limb compared with other intensities of progressive resistance strength training (PRST) in older adults (mean age ≥ 65y) were identified. DATA EXTRACTION: Two reviewers independently completed quality assessment using the Physiotherapy Evidence Database (PEDro) scale and data extraction using a prepared checklist. DATA SYNTHESIS: Twenty-one trials were included. Study quality was fair to moderate (PEDro scale range, 3-7). Studies had small sample sizes (18-84), and participants were generally healthy. Meta-analyses revealed HIPRST improved lower-limb strength greater than moderate- and low-intensity PRST (standardized mean difference [SMD]=.79; 95% confidence interval [CI], .40 to 1.17 and SMD=.83; 95% CI, -.02 to 1.68, respectively). Studies where groups performed equivalent training volumes resulted in similar improvements in leg strength, regardless of training intensity. Similar improvements were found across intensities for functional performance and disability. The effect of intensity of PRST on mood was inconsistent across studies. Adverse events were poorly reported, however, no correlation was found between training intensity and severity of adverse events. CONCLUSIONS: HIPRST improves lower-limb strength more than lesser training intensities, although it may not be required to improve functional performance. Training volume is also an important variable. HIPRST appears to be a safe mode of exercise in older adults. Further research into its effects on older adults with chronic health conditions across the care continuum is required.

Effects of Low- Versus High-Velocity-Loss Thresholds With Similar Training Volume on Maximal Strength and Hypertrophy in Highly Trained Individuals.

AIMS: In the present intervention study, low-velocity-loss (LVL) versus high-velocity-loss (HVL) thresholds in the squat and bench press were compared for changes in muscle strength, power, and hypertrophy. METHODS: Strength-trained volunteers (7♀ and 9♂; age: 27.2 [3.4] y; height: 174.6 [8.0] cm; body mass: 75.3 [10.1] kg) were randomized into an LVL or HVL threshold group (LVL n = 3♀ + 5♂, and HVL n = 4♀ + 4♂). Training took place 3 times per week over 6 weeks (loads: ∼75%-90% of 1-repetition maximum [1RM]). The thresholds of LVLs and HVLs were set at 20% and 40% of maximal velocity, respectively, for the squat, and at 30% and 60%, respectively, for the bench press. Before and after the intervention, 1RM, leg press power, and squat jump were tested. The load (∼45% of 1RM) corresponding to 1-m/s velocity was assessed in all sessions for both exercises. In addition, the thickness of the vastus lateralis and triceps brachii and body composition (dual-energy X-ray absorptiometry [DEXA]) were measured. RESULTS: Squat and bench-press 1RM increased similarly in both groups by 7% to 11% (SD: 4%-6%, P < .05). No group differences were observed for changes in jump height, leg press power, or DEXA lean mass. However, HVL showed a small increase in muscle thickness of the vastus lateralis compared with LVL (6 ± 6% [95% CI] group difference, P < .05). CONCLUSION: For strength-trained individuals, high-volume lower-velocity-loss thresholds were as effective as higher thresholds for improvements in 1RM strength; but local hypertrophy was seemingly elicited faster with higher velocity-loss thresholds.

Effects of vitamin D supplementation on maximal strength and power in athletes: a systematic review and meta-analysis of randomized controlled trials.

Background: Vitamin D is thought to be a powerful modulator of skeletal muscle physiology. However, available data on the effects of vitamin D supplementation on muscle function in athletes are limited and with mixed results. This meta-analysis therefore, aimed to quantitatively summarize the up-to-date literature assessing the effects of vitamin D supplementation on muscle strength and power in athletes. Methods: Sport Discus, PubMed, Cochrane Library and Web of Science were searched to identify randomized controlled trials (RCTs) that used one-repetition maximum (1RM) tests to assess maximal strength, and vertical jump to assess muscle power in athletes. The Cochrane Risk of Bias tool was used to evaluate the included RCTs for sources of bias. The standardized mean difference (SMD) was used as the effect size, interpreted together with its 95% confidence intervals (CI). The effect sizes were calculated on the changes from baseline between vitamin D and placebo groups for maximal strength results by upper body and lower body, and for power results. Results: Eleven RCTs involving 436 athletes were included. The results indicated that if baseline serum 25(OH)D concentration was < 75 nmol/L, the treatment had a small effect on upper body muscle strength [SMD 0.25, 95% CI: (-0.44, 0.95), p = 0.47] and on lower body muscle strength [SMD 0.26, 95% CI: (-0.13, 0.65), p = 0.19]; if the baseline serum 25(OH)D concentration was ≥ 75 nmol/L, the treatment had a trivial effect on muscle power [SMD 0.15, 95% CI: (-0.42, 0.72), p = 0.61]. Discussion: This meta-analysis demonstrated that there is not a statistically significant effect of vitamin D supplementation on improving maximum strength and power, but highlights that further research is required addressing the key limitations in previous studies before definitive conclusions can be made.