Rhonda Orr

Efficacy of progressive resistance training on balance performance in older adults : a systematic review of randomized controlled trials.

The serious health, social and economic consequences of falls are well documented. Lower extremity muscle weakness and power as well as balance impairment are major independent intrinsic contributors to falls and amenable to intervention. Progressive resistance training (PRT) is widely accepted as an appropriate modality for treating sarcopenia and has been reported to improve balance. However, other studies affirm no significant effect of PRT on balance. To date, there is no clear, definitive statement or synthesis of studies that has examined the effect of PRT on balance. Therefore, our objective was to systematically review the literature to probe the merit of PRT as a single intervention on balance performance in older adults. We conducted a comprehensive search of major electronic databases to October 2006, with citation searches and bibliographic searches of journal articles and literature/systematic reviews. Two independent reviewers screened for eligibility and assessed the quality of the studies using the Physiotherapy Evidence Database scale for validity assessment. Randomized controlled trials of PRT only, with any balance outcome in participants with a mean age of ≥60 years (individual minimum age >50 years) were included. Trials that contained more than one intervention, providing the PRT and control groups matched the inclusion criteria, were also included. Because of the heterogeneity of interventions and balance outcomes, a meta-analysis was not performed. However, corrected effect sizes with confidence intervals were determined for each study outcome. Twenty-nine studies were compatible with the inclusion/exclusion criteria and were eligible for review. Participants (n = 2174) included healthy, community-dwelling, mobility-limited, frail cohorts and those with chronic comorbidities. Balance outcomes conducted were extensive and were broadly categorized by the authors as: static, dynamic, functional and computerized dynamic posturography. Some studies used more than one balance outcome. The number of balance tests in all totalled 68. Fourteen studies (15 tests representing 22% of all balance tests) reported improvements, significantly greater than controls, in balance performance following PRT. Improvements were not linked to a particular type of balance performance. The inconsistent effect of PRT on balance may be explained by heterogeneity of cohort and balance tests, variability in methodology of the balance test and sample size, inadequate dose of PRT and/or compliance to training, or lack of statistical power. Standardization of balance testing methodology and better reporting of procedures may ensure greater comparability of results in future studies. It is also possible that PRT alone is not a robust intervention for balance control. This is the first systematic synthesis of the literature to examine the effectiveness of PRT alone on balance performance in older adults. The limited evidence presented in currently published data has not consistently shown that the use of PRT in isolation improves balance in this population. However, further research should explore optimal resistance training regimens that: focus on the muscles most pertinent to balance control, best target neuromuscular adaptations that protect against postural challenges and elucidate mechanism(s) by which PRT may affect balance control.

The Anabolic Androgenic Steroid Oxandrolone in the Treatment of Wasting and Catabolic Disorders Review of Efficacy and Safety

There has been increasing interest in the development of effective agents that can be safely used to promote anabolism in the clinical setting for patients with chronic wasting conditions as well as in the prevention and treatment of frailty associated with loss of muscle tissue in aging (sarcopenia).One such agent is the anabolic androgenic steroid (AAS) oxandrolone, which has been used in such clinical situations as HIV-related muscle wasting, severe burn injury, trauma following major surgery, neuromuscular disorders and alcoholic hepatitis for over 30 years. In the US, oxandrolone is the only AAS that is US FDA-approved for restitution of weight loss after severe trauma, major surgery or infections, malnutrition due to alcoholic cirrhosis, and Duchenne’s or Becker’s muscular dystrophy.Our review of the use of oxandrolone in the treatment of catabolic disorders, HIV and AIDS-related wasting, neuromuscular and other disorders provides strong evidence of its clinical efficacy. Improvements in body composition, muscle strength and function, status of underlying disease or recovery from acute catabolic injury and nutritional status are significant in the vast majority of well designed trials. However, oxandrolone has not yet been studied in sarcopenia.Unlike other orally administered C17α-alkylated AASs, the novel chemical configuration of oxandrolone confers a resistance to liver metabolism as well as marked anabolic activity. In addition, oxandrolone appears not to exhibit the serious hepatotoxic effects (jaundice, cholestatic hepatitis, peliosis hepatis, hyperplasias and neoplasms) attributed to the C17α-alkylated AASs. Oxandrolone is reported to be generally well tolerated and the most commonly documented adverse effects are transient elevations in transaminase levels and reductions in high density lipoprotein cholesterol level.However, optimal risk: benefit ratios for oxandrolone and other agents in its class will need to be refined before widespread clinical acceptance of AASs as a therapeutic option in sarcopenia and other chronic wasting conditions.

Effect of standing posture during whole body vibration training on muscle morphology and function in older adults: A randomised controlled trial

BackgroundWhole body vibration (WBV) is a novel modality of exercise shown to improve musculoskeletal function. This study aims to examine the effects of standing posture during low magnitude WBV training on muscle function and muscle morphology in older adults.MethodsNineteen men and women (50-80 years) were recruited to a three month randomised controlled trial and allocated to one of three groups: WBV with flexed knees (FK), WBV with locked knees (LK), or sham WBV with flexed knees (CON). Exposure was intermittent (1 min WBV:1 min rest) for 20 min, three times per week for 13 weeks. Measurements were taken at baseline and at three months. Primary outcomes included upper and lower body muscle function (strength, power and velocity). Secondary outcomes were muscle morphology, balance, habitual and maximal gait velocity, stair climb power, and chair stand performance.ResultsSixteen subjects completed the study. Relative (%) upper body contraction velocity improved significantly after WBV with FK compared to LK (FK 16.0%, LK -7.6%, CON 4.7, p = 0.01). Relative upper body strength (LK 15.1%, p = 0.02; FK 12.1%, p = 0.04; CON 4.7%) increased significantly following WBV compared to control. Absolute (p = 0.05) and relative (p = 0.03) lower leg strength significantly improved with both standing postures (LK 14.4%; FK 10.7%; CON 1.3%). Only the LK group differed significantly from CON in relative leg strength gains (p = 0.02). Potentially clinically meaningful but statistically non-significant improvements in lower leg muscle cross-sectional area (LK 3.7 cm2, FK 2.4 cm2, CON 2.2 cm2 p = 0.13) were observed after WBV with LK compared to the other groups. No significant effects of WBV on any functional performance tests were observed.ConclusionsOur results suggest that WBV may improve muscle strength and contraction velocity in some muscle groups in older adults. However, hypothesised differential adaptation to standing posture (FK > LK) was observed only for upper body contraction velocity, making recommendations regarding this prescriptive element inconclusive. The efficacy, mechanism of action and long term feasibility of WBV for musculoskeletal health in older adults warrants continued investigation in robustly designed, sufficiently powered future studies.Trial RegistrationACTRN12609000353291.

The effect of whole body vibration exposure on muscle or bone morphology and function in older adults: A systematic review of the literature

CONTEXT AND OBJECTIVE The aim of this study was to examine the effect of whole body vibration (WBV), a novel exercise modality, on muscle or bone morphology and function in older adults. METHODS A literature search of published randomised controlled trials (RCTs) was conducted using multiple databases and hand searching for study designs reporting the effects of WBV in older adults on any outcomes related to muscle function, or muscle or bone morphology. Concomitant exercise was only included if the control group performed the same exercise as the active WBV group, but without vibration. RESULTS Six RCTs met the inclusion criteria of this review, three reporting measures of muscle only, two assessing bone measures only and one detailing measures of both bone and muscle. Study design varied greatly across the six trials and only six of 35 musculoskeletal outcomes analysed were statistically significant. All statistically significant improvements were of muscle function. CONCLUSIONS The published literature to date provides only weak support for the efficacy of WBV exposure for muscle function, muscle morphology, or bone architecture in older adults. Irregularities in study design and WBV protocols across the literature and poor quality trials contribute to this inconsistency, revealing the need for more uniformity in future trials. Future research should be more robust in design, include larger cohorts, longer interventions and standardisation of protocols. They should also investigate the optimal dose-response relationships and variation in vibration characteristics, to determine the true efficacy, clinical relevance, and underlying mechanisms of muscle and bone adaptations.

The effect of whole body vibration exposure on balance and functional mobility in older adults: a systematic review and meta-analysis.

The aim of this review was to systematically evaluate the effect of WBV exposure alone on balance and functional mobility in older adults. A literature search of randomized controlled trials (RCT) reporting the effects of WBV on balance or functional mobility outcomes in older adults, was conducted using multiple databases. WBV-plus-exercise was only included if the control group performed the same exercises as the WBV group, but without vibration. The methodological quality of studies was assessed using the PEDro scale. Meta-analysis was performed if three or more studies measured the same outcome. Twenty RCTs met the inclusion criteria. Eight RCTs compared WBV-only with control and eight RCTs compared WBV-plus-exercise with the same-exercise only group. Meta-analysis indicated that WBV improved single-leg stance (p=0.05) and timed up and go (p=0.004) measures compared with controls. WBV improved other balance and mobility outcomes with inconsistent results. Although balance and mobility appeared to be responsive to WBV-plus-exercise, particularly in lower-functioning patients, compared with WBV-only, caution is required when interpreting the findings. Although there is some evidence for an overall effect of WBV on selected balance and mobility measures, its impact remains inconclusive. Robust RCTs examining WBV-only exposure on balance and functional mobility in older adults are warranted.

The effect of acute and chronic exercise on cognitive function and academic performance in adolescents: A systematic review

OBJECTIVES To investigate whether exercise, proposed to enhance neuroplasticity and potentially cognitive function (CF) and academic performance (AP), may be beneficial during adolescence when important developmental changes occur. DESIGN Systematic review evaluating the impact of acute or chronic exercise on CF and AP in adolescents (13-18 years). METHODS Nine databases (AMED, AusportMed, CINAHL, COCHRANE, Embase, Medline, Scopus, SPORTdiscus, Web of Science) were searched from earliest records to 31st October 2016, using keywords related to exercise, CF, AP and adolescents. Eligible studies included controlled trials examining the effect of any exercise intervention on CF, AP or both. Effect size (ES) (Hedges g) were calculated where possible. RESULTS Ten papers (11 studies) were reviewed. Cognitive domains included: executive function (n=4), memory (n=4), attention/concentration (n=2), visuo-motor speed (n=1), logical sequencing (n=1) and psychometric aptitude (n=1). All papers, nine of 10 being acute studies, reported at least one parameter showing a significant effect of exercise in improving CF and AP. However, the CF parameters displayed substantial heterogeneity, with only 37% favouring acute and chronic exercise. Where ES could be calculated, 52% of the acute CF parameters favoured rest. Memory was the domain most consistently improved by exercise. Academic performance demonstrated a significant improvement with exercise in one of two acute studies and the only chronic study (p≤0.001). CONCLUSIONS The evidence for the effect of exercise on CF and AP in adolescents is equivocal and limited in quantity and quality. Well-designed research is therefore warranted to determine the benefits of exercise in enhancing CF and AP and reducing sedentary behaviour.

Anthropometric characteristics of Australian junior representative rugby league players

OBJECTIVES To comprehensively describe anthropometric characteristics of Australian junior elite rugby league players and assess potential anthropometric dissimilarities between players of varying positional groups, ethnicity (Polynesian vs. non-Polynesian) and playing level (junior vs. professional; using published data from Australian professional players). DESIGN Cross-sectional study. METHODS Height, body mass, eight skinfolds, five girths and two bone breadths were measured with body fat (BF%) and somatotype calculated using population-appropriate equations. DATA mean ± SD. RESULTS This study recruited 116 junior players. Mean age, mass and BF% were 17 ± 1 y, 87.0 ± 11.6 kg and 14.0 ± 4.6% respectively. Compared to backs, forwards had greater mass (92.6 ± 12.2 vs. 80.9 ± 7.1 kg), skinfolds, girths, femur breadth, BF% (16.1 ± 4.8% vs. 11.8 ± 3.2%) (all p<0.01), and were more endo- and mesomorphic, but less ectomorphic (all p<0.001). Compared to other positional groups, props had greater mass, adiposity, calf girth and endomorphy, while adjustables (fullbacks, five-eighths, halfbacks, hookers) had the shortest stature (all p<0.01). Polynesians exhibited greater height (181.0 ± 5.7 vs. 178.7 ± 6.3 cm), mass (90.6 ± 11.7 vs. 84.7 ± 11.1 kg), arm and calf girths, bone breadths and mesomorphy (7.6 ± 1.2 vs. 6.7 ± 1.1) than non-Polynesians (all p<0.05). Juniors had lower height, mass, waist and smaller sum of skinfolds than professional players (all p<0.05). CONCLUSIONS Greater mass, mesomorphy, adiposity and bone size in forwards is desirable for tackling and attacking and may protect against high impact forces sustained in this position. Advantageous anthropometric attributes exhibited in Polynesian players may influence selection into junior elite rugby league teams. Anthropometric data from this study may assist other junior players and coaches with training, dietary modification and position allocation.

Continuous Hemodynamic Response to Maximal Dynamic Strength Testing in Older Adults

OBJECTIVE To quantify acute changes in blood pressure and heart rate during a maximal dynamic strength-single-repetition maximum lift (1-RM)-testing session in older adults with a low burden of chronic disease. DESIGN Descriptive, cross-sectional study. SETTING University rehabilitation center. PARTICIPANTS Volunteer sample of 43 community-dwelling, nonresistance-trained older adults aged 60 years and older (mean, 68+/-6y). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate was obtained by plethysmography at rest and during 1-RM strength testing on leg press, knee extension, and knee flexion resistance machines. RESULTS Average resting SBP (132+/-28mmHg), DBP (54+/-15mmHg), and heart rate (65+/-11 beats/min) were independent of hypertensive diagnosis and overweight status. Maximal SBP, DBP, and heart rate increased significantly during the 1-RM in all exercises compared with rest (P<.001). Highest values of SBP (236+/-51mmHg) and DBP (140+/-46mmHg) were measured during the leg press at 99.5%+/-6.7% of 1-RM. Lowest values of SBP (79+/-25mmHg) and DBP (38+/-15mmHg), and the highest (123+/-44 beats/min) and lowest heart rate (41+/-23 beats/min) were measured during the knee extension at 97.4%+/-8.1% of 1-RM. Absolute falls in SBP were greatest in treated hypertensive participants. No cardiovascular symptoms or events occurred in 129 1-RM tests. CONCLUSIONS Large, very transient, asymptomatic excursions in blood pressure and heart rate were measured during 1-RM testing. The most robust hemodynamic response occurred during the leg press. Thus the leg press may be the most important exercise to focus hemodynamic monitoring efforts upon during strength testing in clinical cohorts.

Analysis of Physical Collisions in Elite National Rugby League Match Play

OBJECTIVE To investigate the impact forces of collision events during both attack and defense in elite rugby league match play and to compare the collision profiles between playing positions. PARTICIPANTS 26 elite rugby league players. METHODS Player collisions were recorded using an integrated accelerometer in global positioning system units (SPI-Pro X, GPSports). Impact forces of collisions in attack (hit-ups) and defense (tackles) were analyzed from 359 files from outside backs (n = 78), adjustables (n = 97), wide-running forwards (n = 136), and hit-up forwards (n = 48) over 1 National Rugby League season. RESULTS Hit-up forwards were involved in 0.8 collisions/min, significantly more than all other positional groups (wide-running forwards P = .050, adjustables P = .042, and outside backs P = .000). Outside backs experienced 25% fewer collisions per minute than hit-up forwards. Hit-up forwards experienced a collision within the 2 highest classifications of force (≥ 10 g) every 2.5 min of match play compared with 1 every 5 and 9 min for adjustables and outside backs, respectively. Hit-up forwards performed 0.5 tackles per minute of match play, 5 times that of outside backs (ES = 1.90; 95% CI [0.26,3.16]), and 0.2 hit-ups per minute of match play, twice as many as adjustables. CONCLUSIONS During a rugby league match, players are exposed to a significant number of collision events. Positional differences exist, with hit-up and wide-running forwards experiencing greater collision events than adjustables and outside backs. Although these results may be unique to the individual teams defensive- and attacking-play strategies, they are indicative of the significant collision profiles in professional rugby league.

The Effect of Whole Body Vibration Exposure on Muscle Function in Children With Cystic Fibrosis: A Pilot Efficacy Trial

Background To examine the effects of whole body vibration (WBV) exposure on muscle function in children with Cystic Fibrosis (CF). Non-randomised controlled cross-over trial. Methods The setting was home-based WBV exposure. The participants were children (8 - 15 years) with CF (n = 7). Intervention: participants served as their own controls for the first four weeks (usual care), then underwent four weeks of parentally-supervised home-based WBV exposure followed by four weeks washout (usual care). The WBV exposure consisted of 20 - 30 minutes of intermittent (1 min vibration:1 min rest) exposure on a Galileo platform (20 - 22Hz, 1 mm amplitude) 3 days/week. The primary outcome measures of absolute and relative lower body (leg extension (LE), leg press (LP)), upper body (chess press (CP)) strength and power, and power were measured at baseline, and weeks 4, 8 and 12. Secondary exploratory outcomes were cardiorespiratory fitness, pulmonary function and health-related quality of life. Results Six participants completed the training without adverse events. Muscle function changes following WBV exposure were not statistically significant. However, moderate-to-large relative effect sizes (ES) favouring WBV were evident for leg extension strength (ES = 0.66 (-0.50, 1.82)), LP relative strength (ES = 0.92 (-0.27, 2.11)), leg press peak power (ES = 0.78 (-0.50, 2.07)) and CMJ height (ES = 0.60 (-0.56 to 1.76)). Conclusions The results from this first controlled trial indicate that WBV may be a potentially effective exercise modality to safely increase leg strength and explosive power in children with CF. Potentially clinically relevant changes support continued investigation of the efficacy, mechanism and feasibility of this intervention in future large-scale studies.