Joel T. Fuller

Effect of vibration on muscle perfusion: a systematic review

Vibration has become of increasing interest to health professionals, primarily owing to reports that vibration can increase tissue blood flow. The aim of this review was to investigate the available scientific evidence on the effects of exogenous vibration on skeletal muscle perfusion. The databases searched from inception to December 2010 included Ovid MEDLINE, EMBASE, CINAHL via EbscoHost and CENTRAL. Experimental and observational studies, where exogenous vibration was an intervention, were included in this review. The main outcomes of interest were muscle blood volume, blood flow, blood flow velocity, arterial diameter and muscle temperature. One reviewer selected studies for inclusion, extracted data and assessed the quality of the eligible studies. Percentage change in muscle perfusion outcome was the measure of treatment effect, and regression analysis was used to investigate associations between vibratory load and muscle perfusion. Twenty‐two studies with a total of 302 participants were included in this review. Muscle blood volume increased with vibration in five of nine studies and decreased in two studies; muscle blood flow velocity increased with vibration in five of six studies; muscle blood flow increased with vibration in two of three studies; vibration had a positive effect on arterial diameter in three of three studies; vibration had no effect on muscle temperature in two of two studies. The magnitude of increase in muscle perfusion was positively associated with vibratory load (P<0·001). We conclude that vibration increases muscle perfusion with the magnitude of increase positively related to the vibratory load applied.

The long-term effect of minimalist shoes on running performance and injury: design of a randomised controlled trial.

Introduction The outcome of the effects of transitioning to minimalist running shoes is a topic of interest for runners and scientists. However, few studies have investigated the longer term effects of running in minimalist shoes. The purpose of this randomised controlled trial (RCT) is to investigate the effects of a 26 week transition to minimalist shoes on running performance and injury risk in trained runners unaccustomed to minimalist footwear. Methods and analysis A randomised parallel intervention design will be used. Seventy-six trained male runners will be recruited. To be eligible, runners must be aged 18–40 years, run with a habitual rearfoot footfall pattern, train with conventional shoes and have no prior experience with minimalist shoes. Runners will complete a standardised transition to either minimalist or control shoes and undergo assessments at baseline, 6 and 26 weeks. 5 km time-trial performance (5TT), running economy, running biomechanics, triceps surae muscle strength and lower limb bone mineral density will be assessed at each time point. Pain and injury will be recorded weekly. Training will be standardised during the first 6 weeks. Primary statistical analysis will compare 5TT between shoe groups at the 6-week time point and injury incidence across the entire 26-week study period. Ethics and dissemination This RCT has been approved by the Human Research Ethics Committee of the University of South Australia. Participants will be required to provide their written informed consent prior to participation in the study. Study findings will be disseminated in the form of journal publications and conference presentations after completion of planned data analysis. Trial registration number This RCT has been registered with the Australian New Zealand Clinical Trials Registry (ACTRN12613000642785).

Redistribution of Mechanical Work at the Knee and Ankle Joints During Fast Running in Minimalist Shoes

CONTEXT Minimalist shoes have been suggested as a way to alter running biomechanics to improve running performance and reduce injuries. However, to date, researchers have only considered the effect of minimalist shoes at slow running speeds. OBJECTIVE To determine if runners change foot-strike pattern and alter the distribution of mechanical work at the knee and ankle joints when running at a fast speed in minimalist shoes compared with conventional running shoes. DESIGN Crossover study. SETTING Research laboratory. PATIENTS OR OTHER PARTICIPANTS Twenty-six trained runners (age = 30.0 ± 7.9 years [age range, 18-40 years], height = 1.79 ± 0.06 m, mass = 75.3 ± 8.2 kg, weekly training distance = 27 ± 15 km) who ran with a habitual rearfoot foot-strike pattern and had no experience running in minimalist shoes. INTERVENTION(S) Participants completed overground running trials at 18 km/h in minimalist and conventional shoes. MAIN OUTCOME MEASURE(S) Sagittal-plane kinematics and joint work at the knee and ankle joints were computed using 3-dimensional kinematic and ground reaction force data. Foot-strike pattern was classified as rearfoot, midfoot, or forefoot strike based on strike index and ankle angle at initial contact. RESULTS We observed no difference in foot-strike classification between shoes (χ21 = 2.29, P = .13). Ankle angle at initial contact was less (2.46° versus 7.43°; t25 = 3.34, P = .003) and strike index was greater (35.97% versus 29.04%; t25 = 2.38, P = .03) when running in minimalist shoes compared with conventional shoes. We observed greater negative (52.87 J versus 42.46 J; t24 = 2.29, P = .03) and positive work (68.91 J versus 59.08 J; t24 = 2.65, P = .01) at the ankle but less negative (59.01 J versus 67.02 J; t24 = 2.25, P = .03) and positive work (40.37 J versus 47.09 J; t24 = 2.11, P = .046) at the knee with minimalist shoes compared with conventional shoes. CONCLUSIONS Running in minimalist shoes at a fast speed caused a redistribution of work from the knee to the ankle joint. This finding suggests that runners changing from conventional to minimalist shoes for short-distance races could be at an increased risk of ankle and calf injuries but a reduced risk of knee injuries.

High prevalence of dysfunctional, asymmetrical, and painful movement in elite junior Australian Football players assessed using the Functional Movement Screen.

OBJECTIVES The purpose of this study was to describe the prevalence of dysfunctional, asymmetrical, and painful movement in junior Australian Football players using the Functional Movement Screen (FMS). DESIGN Cross-sectional study. METHODS Elite junior male Australian Football players (n=301) aged 15-18 years completed pre-season FMS testing. The FMS consists of 7 sub-tests: deep squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, trunk stability push-up (TSPU) and rotary stability. The shoulder mobility, TSPU, and rotary stability tests were combined with an accompanying clearing test to assess pain. Each sub-test was scored on an ordinal scale from 0 to 3 and summed to give a composite score out of 21. Composite scores ≤14 were operationally defined as indicating dysfunctional movement. Players scoring differently on left and right sides were considered asymmetrical. Players reported whether they missed any games due to injury in the preceding 22 game season. RESULTS Sixty percent of players (n=182) had composite scores ≤14, 65% of players (n=196) had at least one asymmetrical sub-test, and 38% of players (n=113) had at least one painful sub-test. Forty-two percent of players (n=126) missed at least one game in the previous season due to injury. Previous injury did not influence composite score (p=0.951) or asymmetry (p=0.629). Players reporting an injury during the previous season were more likely to experience pain during FMS testing (odds ratio 1.97, 95% confidence interval 1.23-3.18; p=0.005). CONCLUSIONS Junior Australian Football players demonstrate a high prevalence of dysfunctional, asymmetrical, and painful movement during FMS testing.

Effects of a minimalist shoe on running economy and 5-km running performance

ABSTRACT The purpose of this study was to determine if minimalist shoes improve time trial performance of trained distance runners and if changes in running economy, shoe mass, stride length, stride rate and footfall pattern were related to any difference in performance. Twenty-six trained runners performed three 6-min sub-maximal treadmill runs at 11, 13 and 15 km·h−1 in minimalist and conventional shoes while running economy, stride length, stride rate and footfall pattern were assessed. They then performed a 5-km time trial. In the minimalist shoe, runners completed the trial in less time (effect size 0.20 ± 0.12), were more economical during sub-maximal running (effect size 0.33 ± 0.14) and decreased stride length (effect size 0.22 ± 0.10) and increased stride rate (effect size 0.22 ± 0.11). All but one runner ran with a rearfoot footfall in the minimalist shoe. Improvements in time trial performance were associated with improvements in running economy at 15 km·h−1 (r = 0.58), with 79% of the improved economy accounted for by reduced shoe mass (P < 0.05). The results suggest that running in minimalist shoes improves running economy and 5-km running performance.

Body mass and weekly training distance influence the pain and injuries experienced by runners using minimalist shoes: a randomized controlled trial

Background: Minimalist shoes have been popularized as a safe alternative to conventional running shoes. However, a paucity of research is available investigating the longer-term safety of minimalist shoes. Purpose: To compare running-related pain and injury between minimalist and conventional shoes in trained runners and to investigate interactions between shoe type, body mass, and weekly training distance. Study Design: Randomized clinical trial; Level of evidence, 2. Methods: Sixty-one trained, habitual rearfoot footfall runners (mean ± SD: body mass, 74.6 ± 9.3 kg; weekly training distance, 25 ± 14 km) were randomly allocated to either minimalist or conventional shoes. Runners gradually increased the time spent running in their allocated shoes over 26 weeks. Running-related pain intensity was measured weekly by use of 100-mm visual analog scales. Time to first running-related injury was also assessed. Results: Interactions were found between shoe type and weekly training distance for weekly running-related pain; greater pain was experienced with minimalist shoes (P < .05), and clinically meaningful increases (>10 mm) were noted when the weekly training distance was more than 35 km/wk. Eleven of 30 runners sustained an injury in conventional shoes compared with 16 of 31 runners in minimalist shoes (hazard ratio, 1.64; 95% confidence interval, 0.63-4.27; P = .31). A shoe × body mass interaction was found for time to first running-related injury (P = .01). For runners using minimalist shoes, relative to runners using conventional shoes, the risk of sustaining an injury became more likely with increasing body mass above 71.4 kg, and the risk was moderately increased (hazard ratio, 2.00; 95% confidence interval, 1.10-3.66; P = .02) for runners using minimalist shoes who had a body mass of 85.7 kg. Conclusions: Runners should limit weekly training distance in minimalist shoes to avoid running-related pain. Heavier runners are at greater risk of injury when running in minimalist shoes. Registration: Australian New Zealand Clinical Trials Registry (ACTRN12613000642785).

The effect of footwear and footfall pattern on running stride interval long-range correlations and distributional variability

The presence of long-range correlations (self-similarity) in the stride-to-stride fluctuations in running stride interval has been used as an indicator of a healthy adaptable system. Changes to footfall patterns when running with minimalist shoes could cause a less adaptable running gait. The purpose of this study was to investigate stride interval variability and the degree of self-similarity of stride interval in runners wearing minimalist and conventional footwear. Twenty-six trained habitual rearfoot footfall runners, unaccustomed to running in minimalist footwear, performed 6-min sub-maximal treadmill running bouts at 11, 13 and 15 km·h(-1) in minimalist and conventional shoes. Force sensitive resistors were placed in the shoes to quantify stride interval (time between successive foot contacts). Footfall position, stride interval mean and coefficient of variation (CV), were used to assess performance as a function of shoe type. Long-range correlations of stride interval were assessed using detrended fluctuation analysis (α). Mean stride interval was 1-1.3% shorter (P=0.02) and 27% of runners adopted a midfoot footfall (MFF) in the minimalist shoe. There was a significant shoe effect on α and shoe*speed*footfall interaction effect on CV (P<0.05). Runners that adopted a MFF in minimalist shoes, displayed reduced long-range correlations (P<0.05) and CV (P<0.06) in their running stride interval at the 15 km·h(-1) speed. The reduced variability and self-similarity observed for runners that changed to a MFF in the minimalist shoe may be suggestive of a system that is less flexible and more prone to injury.

Vibration therapy is no more effective than the standard practice of massage and stretching for promoting recovery from muscle damage after eccentric exercise

Objective:The purpose of this study was to determine if vibration therapy is more effective than the standard treatment of stretching and massage for improving recovery of muscle strength and reducing muscle soreness after muscle damage induced by eccentric exercise. Design:A randomized, single-blinded parallel intervention trial design was used. Setting:Research laboratory. Participants:Fifty untrained men aged 18 to 30 years completed the study. Interventions:Participants performed 100 maximal eccentric muscle actions (ECCmax) of the right knee extensor muscles. For the next 7 days, 25 participants applied cycloidal vibration therapy to the knee extensors twice daily and 25 participants performed stretching and sports massage (SSM) twice daily. Main Outcome Measures:Changes in markers of muscle damage [peak isometric torque (PIT), serum creatine kinase (CK), and serum myoglobin (Mb)], muscle soreness (visual analog scale), and inflammation [serum C-reactive protein (CRP)] were assessed. Results:After ECCmax, there was no difference in recovery of PIT and muscle soreness or serum CK, Mb, and CRP levels between vibration and SSM groups (P > 0.28). Conclusions:Cycloidal vibration therapy is no more effective than the standard practice of stretching and massage to promote muscle recovery after the performance of muscle-damaging exercise. Clinical Relevance:Prescription of vibration therapy after maximal exercise involving eccentric muscle damage did not alleviate signs and symptoms of muscle damage faster than the standard prescription of stretching and massage.

Six-week transition to minimalist shoes improves running economy and time-trial performance

OBJECTIVES This study investigated if gradually introducing runners to minimalist shoes during training improved running economy and time-trial performance compared to training in conventional shoes. Changes in stride rate, stride length, footfall pattern and ankle plantar-flexor strength were also investigated. DESIGN Randomised parallel intervention trial. METHODS 61 trained runners gradually increased the amount of running performed in either minimalist (n=31) or conventional (n=30) shoes during a six-week standardised training program. 5-km time-trial performance, running economy, ankle plantar-flexor strength, footfall pattern, stride rate and length were assessed in the allocated shoes at baseline and after training. Footfall pattern was determined from the time differential between rearfoot and forefoot (TDR-F) pressure sensors. RESULTS The minimalist shoe group improved time-trial performance (effect size (ES): 0.24; 95% confidence interval (CI): 0.01, 0.48; p=0.046) and running economy (ES 0.48; 95%CI: 0.22, 0.74; p<0.001) more than the conventional shoe group. There were no minimalist shoe training effects on ankle plantar-flexor concentric (ES: 0.11; 95%CI: -0.18, 0.41; p=0.45), isometric (ES: 0.23; 95%CI: -0.17, 0.64; p=0.25), or eccentric strength (ES: 0.24; 95%CI: -0.17, 0.65; p=0.24). Minimalist shoes caused large reductions in TDR-F (ES: 1.03; 95%CI: 0.65, 1.40; p<0.001) but only two runners changed to a forefoot footfall. Minimalist shoes had no effect on stride rate (ES: 0.04; 95%CI: -0.08, 0.16; p=0.53) or length (ES: 0.06; 95%CI: -0.06, 0.18; p=0.35). CONCLUSIONS Gradually introducing minimalist shoes over a six-week training block is an effective method for improving running economy and performance in trained runners.

Therapeutic effects of aerobic and resistance exercises for cancer survivors: a systematic review of meta-analyses of clinical trials

Objective To systematically appraise and summarise meta-analyses investigating the effect of exercise compared with a control condition on health outcomes in cancer survivors. Design Umbrella review of intervention systematic reviews. Data sources Web of Science, Scopus, Cochrane Library, CINAHL and MEDLINE databases were searched using a predefined search strategy. Eligibility criteria Eligible meta-analyses compared health outcomes between cancer survivors participating in an exercise intervention and a control condition. Health outcomes were cardiovascular fitness, muscle strength, health-related quality of life, cancer-related fatigue and depression. Pooled effect estimates from each meta-analysis were quantified using standardised mean differences and considered trivial (<0.20), small (0.20–0.49), moderate (0.50–0.79) and large (≥0.80). Findings were summarised using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Results There were 65 eligible articles that reported a total of 140 independent meta-analyses. 139/140 meta-analyses suggested a beneficial effect of exercise. The beneficial effect was statistically significant in 104 (75%) meta-analyses. Most effect sizes were moderate for cardiovascular fitness and muscle strength and small for cancer-related fatigue, health-related quality of life and depression. The quality of evidence was variable according to the GRADE scale, with most studies rated low or moderate quality. Median incidence of exercise-related adverse events was 3.5%. Conclusion Exercise likely has an important role in helping to manage physical function, mental health, general well-being and quality of life in people undergoing and recovering from cancer and side effects of treatment. PROSPERO registration number CRD42015020194.