Study protocol - assessing parkrun for walking rehabilitation for people living with, and beyond, cancer: acceptability, adherence, social support and physical function.

INTRODUCTION: Due to a variety of barriers, the majority of cancer survivors do not do enough physical activity to meet current recommendations. This study will assess the feasibility of participation in parkrun walk-run events as a novel mode of community rehabilitation exercise. METHODS: This protocol describes a single-arm intervention study with participants acting as their own controls. The study accepts adults diagnosed with any type of cancer, undergoing treatment or in remission. Participants must be able to walk and have medical clearance to exercise. A sample of 100 participants will be recruited across the Sunshine Coast over two years. Data will be collected over 9-months at 4 time points: Baseline (T1); after 4-weeks of usual daily activities and cancer management prior to parkrun participation(T2); after a 6-month parkrun intervention (T3); at 2-month follow-up (T4). The primary objectives are to assess the acceptability of, and adherence to, parkrun as rehabilitation exercise. Secondary outcomes include wellness, health-related quality of life, anxiety, depression, mood, physical function, parkrun metrics, dietary intake, and diet and exercise behaviour. CONCLUSION: This study will be the first to examine the long-term effects of parkrun as a cancer rehabilitation modality with regard to physical function, psychosocial outcomes and dietary intake. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry ACTRN12623000473662 registered 09/05/2023.Approved by UniSC Human Research Ethics Committee (A221828) and the UK parkrun Research Board. Original protocol. Authors SB, RB, HHW, MM, YK.

Meta-analysis prediction intervals are under reported in sport and exercise medicine.

AIM: Prediction intervals are a useful measure of uncertainty for meta-analyses that capture the likely effect size of a new (similar) study based on the included studies. In comparison, confidence intervals reflect the uncertainty around the point estimate but provide an incomplete summary of the underlying heterogeneity in the meta-analysis. This study aimed to estimate (i) the proportion of meta-analysis studies that report a prediction interval in sports medicine; and (ii) the proportion of studies with a discrepancy between the reported confidence interval and a calculated prediction interval. METHODS: We screened, at random, 1500 meta-analysis studies published between 2012 and 2022 in highly ranked sports medicine and medical journals. Articles that used a random effect meta-analysis model were included in the study. We randomly selected one meta-analysis from each article to extract data from, which included the number of estimates, the pooled effect, and the confidence and prediction interval. RESULTS: Of the 1500 articles screened, 866 (514 from sports medicine) used a random effect model. The probability of a prediction interval being reported in sports medicine was 1.7% (95% CI = 0.9%, 3.3%). In medicine the probability was 3.9% (95% CI = 2.4%, 6.6%). A prediction interval was able to be calculated for 220 sports medicine studies. For 60% of these studies, there was a discrepancy in study findings between the reported confidence interval and the calculated prediction interval. Prediction intervals were 3.4 times wider than confidence intervals. CONCLUSION: Very few meta-analyses report prediction intervals and hence are prone to missing the impact of between-study heterogeneity on the overall conclusions. The widespread misinterpretation of random effect meta-analyses could mean that potentially harmful treatments, or those lacking a sufficient evidence base, are being used in practice. Authors, reviewers, and editors should be aware of the importance of prediction intervals.

Does lower extremity alignment during normal stance predict lower limb kinematics and kinetics during drop landings?

BACKGROUND: Static lower extremity alignment (LEA) during normal stance has been used clinically as a tool to determine the presence of known anterior cruciate ligament (ACL) risk factors during dynamic tasks. Previous work investigating the relationship between static LEA during normal stance and risk factors for ACL injury is limited by the use of imprecise methods or because it focuses on knee valgus only and no other potentially important variables. The aim of this investigation was to determine the relationships between static LEA and the corresponding LEA during drop landings. METHODS: Forty-one female athletes were recruited for the study (age: 19.8 ± 2.5 years, height: 1.73 ± 0.06 m, mass: 64.03 ± 6.66 kg). Lower limb kinematic data were collected using a 10 camera infrared motion capture system (500 Hz) with retro-reflective markers placed over key anatomical landmarks. This system was linked to two force platforms (1000 Hz) with subsequent three-dimensional kinematic and kinetic data developed using standard software (Visual3D). Following an appropriate warm-up, data collection involved participants standing with their arms partially abducted to record static LEA. This was following by a series of drop landings from a 0.4 m box onto the force platforms. Maximum LEA data during drop landings were then compared with static LEA. RESULTS: Analyses showed that in comparison to static stance, during landings the anterior tilt of the pelvis decreased while hip abduction and knee internal rotation increased. At best, static LEA variables were moderately correlated (r = -0.51 to 0.58) with peak values measured during drop landings. Additionally, regression analysis did not yield any significant predictors of any key peak hip or knee variables measured during drop landings (p = 0.15 to 0.89). CONCLUSION: When combined, the poor relationships observed between kinematics during static LEA and LEA during drop landings calls into question the practice of using static measures to predict LEA during even simple landing tasks. These findings suggest static assessments of LEA may have minimal value as an ACL injury screening tool.

Alternatives to common approaches for training change of direction performance: a scoping review.

BACKGROUND: Research focuses heavily upon the effect of strength and power training on change of direction performance. The objective of this scoping review is to highlight alternative approaches to training change of direction. METHODS: Four databases (Scopus, PubMed, Web of Science and SPORTDiscus) were searched with no date restrictions. To be included studies must (i) investigate change of direction performance following an intervention or investigate the relationships between variables of interest and change of direction performance; (ii) recruit participants > 18 years old; (iii) recruit participants involved in competitive sport. The majority of included studies investigated the effect of strength and/or power training, or, relationships between strength and/or power variables with change of direction performance. RESULTS: Despite fewer studies, alternative training methods resulted in greater improvements (compared with strength and/or power) in change of direction performance, with smaller training durations. Few studies included reactive agility as an outcome measure. CONCLUSION: Despite much of the literature focusing on strength and/or power, there are alternative training modalities that demonstrate merit for improving change of direction performance. Future studies should investigate the effect of alternative training interventions on reactive agility performance, to provide a more valid indication of transfer to competition.

Lower knee flexion and hip extension rate of torque development in athletes with previous hamstring strain injury.

Persistent deficits in strength and voluntary activation have been observed in athletes with a history of hamstring strain injury. The mechanisms contributing to these deficits are poorly understood and consequently may not be appropriately addressed during rehabilitation. This study aimed to investigate the impact of intended knee flexor contraction mode (concentric, eccentric or isometric) on the rate of torque development and surface electromyography (sEMG) rise in athletes with and without a history of unilateral hamstring strain injury. The impact of the previous injury on hip extensor rate of torque development was also investigated. Previously injured limbs exhibited a slower rate of torque development (mean difference = -31%, p = 0.02, Cohen's d = 0.62) and biceps femoris rate of sEMG rise (mean difference = -181% · s-1, p = 0.003, Cohen's d = 1.10) during intended eccentric knee flexor contractions compared with control limbs. Previously injured (mean difference = -29%, p = 0.01, Cohen's d = 0.85) and contralateral uninjured limbs (mean difference = -31%, p = 0.007, Cohen's d = 0.73) exhibited a slower rate of torque development during isometric hip extensor contractions compared with control limbs. These findings may highlight lower levels of descending input to hamstring motoneurons in previously injured athletes.

Short-term heat acclimation preserves knee extensor torque but does not improve 20 km self-paced cycling performance in the heat.

PURPOSE: This study investigated the effect of 5 days of heat acclimation training on neuromuscular function, intestinal damage, and 20 km cycling (20TT) performance in the heat. METHODS: Eight recreationally trained males completed two 5-day training blocks (cycling 60 min day-1 at 50% peak power output) in a counter-balanced, cross-over design, with a 20TT completed before and after each block. Training was conducted in hot (HA: 34.9 ± 0.7 °C, 53 ± 4% relative humidity) or temperate (CON: 22.2 ± 2.6 °C, 65 ± 8% relative humidity) environment. All 20TTs were completed in the heat (35.1 ± 0.5 °C, 51 ± 4% relative humidity). Neuromuscular assessment of knee extensors (5 × 5 s maximum voluntary contraction; MVC) was completed before and after each 20TT and on the first and last days of each training block. RESULTS: MVC torque was statistically higher after 5 days of HA training compared to CON (mean difference = 14 N m [95% confidence interval; 6, 23]; p < 0.001; d = 0.77). However, 20TT performance after 5 days of HA training was not statistically different to CON, with a between-conditions mean difference in the completion time of 68 s [95% confidence interval; - 9, 145] (p = 0.076; d = 0.35). CONCLUSION: Short-term heat acclimation training may increase knee extensor strength without changes in central fatigue or intestinal damage. Nevertheless, it is insufficient to improve 20 km self-paced cycling performance in the heat compared to workload-matched training in a temperate environment. These data suggest that recreationally trained athletes gain no worthwhile performance advantage from short-term heat-training before competing in the heat.

Voluntary Activation and Reflex Responses after Hamstring Strain Injury.

INTRODUCTION: There is a lack of definitive evidence supporting deficits in voluntary activation in participants with prior hamstring injury; moreover, it remains unknown if spinal mechanisms contribute to suspected deficits. PURPOSE: This study aimed to determine the effect of prior hamstring strain injury on knee flexor concentric and eccentric strength, voluntary activation, surface electromyographic (sEMG) activity, and stretch and tendon reflex amplitudes. METHODS: Twenty-five participants were recruited, 12 with a history of unilateral hamstring strain injury of at least moderate severity. Voluntary activation, strength, and sEMG activity were recorded during maximal eccentric and concentric knee flexor contractions at 60°·s. Stretch and tendon reflexes were also recorded at rest. RESULTS: Previously injured limbs exhibited lower levels of voluntary activation (mean difference = -24.1%, 95% confidence interval [CI] = -34.1% to -14.0%, P < 0.001), strength (mean difference vs control group = -0.37 Nm·kg, 95% CI = -0.71% to -0.03 N·m·kg, P = 0.03), and normalized sEMG (mean difference = -17%, 95% CI = -32% to -2%, P = 0.02) during maximal eccentric knee flexor contractions compared with control group. No such differences were seen in concentric contractions. Stretch reflexes (mean difference = -3.8%, 95% CI = -6.8 to -0.8, P = 0.02) and tendon reflexes (mean difference = -13%, 95% CI = -26% to 0%, P = 0.04) were also lower in previously injured compared with control biceps femoris muscles. CONCLUSION: Moderate to severe hamstring strain injury is associated with long-term deficits in voluntary activation during maximal eccentric contraction. Hamstring injury history is also associated with deficits in stretch reflex and tendon reflex amplitude.

Effect of concentric and eccentric hamstring training on sprint recovery, strength and muscle architecture in inexperienced athletes.

OBJECTIVES: To investigate whether five-weeks of concentric (CON) or eccentric (ECC) hamstring strength training have different effects on recovery from sprint running, eccentric strength and architecture of the biceps femoris long head (BFLH). DESIGN: Cohort study. METHODS: Thirty males (age, 22.8±4.1y; height, 180.1±6.4cm; weight, 85.2±14.6kg) were allocated into either a CON or ECC group, both performing nine sessions of resistance training. Prior to and immediately after the five-week intervention, each participant's BFLH fascicle length (FL), pennation angle (PA), muscle thickness (MT), peak isometric KF torque and Nordic eccentric strength were assessed. Post-intervention, participants performed two timed sprint sessions (10×80m) 48h apart. Blood samples and passive KF torques were collected before, immediately after, 24h and 48h after the first sprint session. RESULTS: After five-weeks of strength-training, fascicles lengthened in the ECC (p<0.001; d=2.0) and shortened in the CON group (p<0.001; d=0.92), while PA decreased for the ECC (p=0.001; d=0.52) and increased in the CON group (p<0.001; d=1.69). Nordic eccentric strength improved in both ECC (p<0.001; d=1.49) and CON (p<0.001; d=0.95) groups. No between-group differences were observed in peak isometric strength (p=0.480), passive KF torques (p=0.807), sprint performance decrements between sprint sessions (p=0.317) and creatine kinase (p=0.818). CONCLUSIONS: Despite inducing significant differences in BFLH muscle architecture, there were no significant between group differences in sprint performance decrements across two sprint sessions.