Medicine and Science in Sports and Exercise

PURPOSE: Short periods of limb immobilization lower myofibrillar protein synthesis rates. Within skeletal muscle, the extracellular matrix of connective proteins is recognized as an important factor determining the capacity to transmit contractile force. Little is known regarding the impact of immobilization and subsequent recovery on muscle connective protein synthesis rates. This study examined the impact of one week of leg immobilization and two weeks of subsequent ambulant recovery on daily muscle connective protein synthesis rates...

PURPOSE: To investigate the effects of a demanding military field exercise on physical performance, body composition and muscle cellular outcomes in men and women. METHODS: Ten men (20.5 ± 0.5 years) and 8 women (21.4 ± 1.4 years) completed a 10-day field exercise consisting of extensive physical activity with food and sleep restriction. Acquisition of body composition, physical performance, blood and muscle biopsies samples were done before and 1,7 and 14 days after the exercise...

PURPOSE: We sought to determine if supramaximal exercise testing confirms the achievement of V̇O2max in acute hypoxia. We hypothesized that the incremental and supramaximal V̇O2 will be sufficiently similar in acute hypoxia. METHODS: Twenty-one healthy adults (males n = 13, females n = 8) completed incremental and supramaximal exercise tests in normoxia and acute hypoxia (fraction inspired oxygen = 0.14) separated by at least 48 hours. Incremental exercise started at 80 and 60 W in normoxia and 40 and 20 W in hypoxia for males and females, respectively, with all increasing by 20 W each minute until volitional exhaustion...

PURPOSE: This study aimed to compare the responsiveness of patient-reported and device-based instruments within four physical activity trials. METHODS: This was a secondary analysis of four randomised trials that used both a patient-reported outcome measure (the Incidental and Planned Exercise Questionnaire, IPEQ) and a device-based instrument (ActiGraph or ActivPAL) to measure physical activity. The four trials included were (i) Activity and MObility UsiNg Technology (AMOUNT): digitally-enabled exercises in those undertaking aged care and neurological rehabilitation; (ii) Balance Exercise Strength Training (BEST) at Home: home-based balance and strength exercises in community-dwelling people aged ≥65 years; (iii) Coaching for Healthy AGEing (CHAnGE): physical activity coaching and fall prevention intervention in community-dwelling people aged ≥60 years; and (iv) Fitbit trial: fall prevention and physical activity promotion with health coaching and activity monitor in community-dwelling people aged ≥60 years...

PURPOSE: This study examined the validity of standard clinical measures of arch height mobility (AHM), midfoot width mobility (MWM) and foot mobility magnitude (FMM) relative to skin-based and osseous measures derived from radiographs. METHODS: Skin-based clinical indices of foot mobility were calculated from standard, caliper-based measures of foot length, midfoot width and dorsal arch height of the left limb of 20 healthy participants (8-71 years) during nonweightbearing and weightbearing...

INTRODUCTION: Treatment options for adolescent patellofemoral pain (PFP) are limited. School footwear might be a suitable intervention to modulate patellofemoral joint (PFJ) loads in adolescents with PFP. This study examined the immediate effects of a flat, flexible school shoe compared to a traditional school shoe on knee joint kinematics and kinetics, and PFJ reaction force during walking and running in adolescents with PFP. METHODS: 28 adolescents (12 female, 16 male, mean ± standard deviation age 14...

PURPOSE: The purpose of this study is to characterize the effect of sex and the influence of oral contraception usage on musculotendinous injury (MTI). Current literature suggests a disparity in the incidence of MTIs between males and females. This may be attributed to inherent biological differences between the sexes, such as in the sex hormonal milieu. There is a lack of information associating sex hormone milieu and MTI. METHODS: We searched the PearlDiver database (a for-fee healthcare database) for males, females taking oral contraceptives (OC), and eumenorrheic females not taking any form of hormonal contraceptives (non-OC) aged 18-39...

PURPOSE: Sprinting often provokes hip pain in individuals with femoroacetabular impingement syndrome (FAIS). Asphericity of the femoral head-neck junction (cam morphology) characteristic of FAIS can increase risk of anterior-superior acetabular cartilage damage. This study aimed to: 1) compare hip contact forces (magnitude and direction) during sprinting between individuals with FAIS, asymptomatic cam morphology (CAM), and controls without cam morphology, and 2) identify the phases of sprinting with high levels of anteriorly directed hip contact forces...

PURPOSE: The purpose of this cross-sectional evaluation was to determine the associations between raw bioelectrical impedance and cardiometabolic health parameters in a sample of young non-Hispanic White and African-American adults. METHODS: A total of 96 (F: 52, M: 44) non-Hispanic White (n = 45) and African-American adults (n = 51) between the ages of 19 and 37 (22.7 ± 3.83 y) completed several fasted assessments including resting systolic blood pressure (rSBP), blood glucose (FBG), blood lipids, and bioelectrical impedance spectroscopy (BIS)...

PURPOSE: The purpose of this study was to determine how the intersection of coactivator-associated arginine methyltransferase 1 (CARM1) and biological sex impacts skeletal muscle adaptations to chronic physical activity. METHODS: 12-week-old female (F) and male (M) wild-type (WT) and CARM1 skeletal muscle-specific knockout mice (mKO) were randomly assigned to sedentary (SED) or voluntary wheel running (VWR) experimental groups. For 8 weeks, the animals in the VWR cohort had volitional access to running wheels...

PURPOSE: This study aimed to evaluate whether motor-respiratory coupling (MRC) exists in rhythmic isometric handgrip exercises and its effect on endurance performance. Additionally, the mechanism underlying observed effects was to be investigated if higher MRC rate could enhance endurance performance. METHODS: Eleven subjects completed three rhythmic isometric handgrip trials to task failure in a randomized manner. After one pre-training session to determine personal grip frequency, one trial was performed without respiration requirement (CON), and two trials were performed with inspiration-motor coupling (IMC) or expiration-motor coupling (EMC)...

PURPOSE: This study aims to investigate the relationships of moderate-to-vigorous physical activity (MVPA) with all-cause and disease-specific mortality. We also investigated how the association between MVPA at leisure time (LT-MVPA) and health outcomes differs at different MVPA at work (WT-MVPA) levels. METHODS: The 81,601 community-dwelling Japanese persons aged 50-79 years who responded to a questionnaire in 2000-2003 were followed until 2018. Cox proportional hazard model was used to examine the association of total MVPA with risks of all-cause, cancer, heart disease, stroke and respiratory disease mortality...

PURPOSE: As high rates of vitamin D deficiency have been demonstrated in orthopaedic patient cohorts, this study aims to characterize the association between a diagnosis of hypovitaminosis D and primary rotator cuff tear (RCT), primary rotator cuff repair (RCR), and postoperative complications in different sex and age cohorts. METHODS: In this retrospective cohort study using PearlDiver, a nationwide administrative claims database, records for all patients aged 30 to 89 who received a diagnosis of hypovitaminosis D between January 1st, 2011 to October 31st, 2018 were queried...

Musculoskeletal injuries occur frequently in sport during practice, training and competition. Injury assessment and management are common responsibilities for the team physician. Initial Assessment and Management of Musculoskeletal Injury - A Team Physician Consensus Statement is title 23 in a series of annual consensus documents written for the practicing team physician. This statement was developed by the Team Physician Consensus Conference (TPCC), an annual project-based alliance of six major professional associations...

PURPOSE: To evaluate patellar tendon loading profiles (loading index, based on loading peak, loading impulse, and loading rate) of rehabilitation exercises to develop clinical guidelines to incrementally increase the rate and magnitude of patellar tendon loading during rehabilitation. METHODS: Twenty healthy adults (10 females/10 males, 25.9 ± 5.7 years) performed 35 rehabilitation exercises, including different variations of squats, lunge, jumps, hops, landings, running, and sports specific tasks...

PURPOSE: Several mechanisms have been proposed to explain how mental fatigue degrades sport performance. In terms of endurance performance, a role for an increased perceived exertion has been demonstrated. Utilizing electroencephalography (EEG) and, more specifically, the movement-related cortical potential (MRCP), the present study explored the neural mechanisms that could underly the mental fatigue-associated increase in perceived exertion. METHODS: Fourteen participants (age: 23 ± 2 y, 5 females, 9 males) performed one familiarisation and two experimental trials in a randomised, blinded, cross-over study design...

INTRODUCTION/PURPOSE: Fatigue is an established prognostic indicator of mortality risk. It remains unknown whether fatigability anchored to a physical task is a more sensitive prognostic indicator and whether sensitivity differs by prevalent chronic conditions. METHODS: 1,076 physically well-functioning participants aged ≥50 years in the Baltimore Longitudinal Study of Aging self-reported fatigue (unusual tiredness or low energy) and had perceived fatigability assessed after a standardized treadmill walk...

PURPOSE: To summarise and meta-analyse existing evidence regarding the influence of CYP1A2 genotypes on the acute effects of caffeine for exercise performance, and to investigate the interaction between genotype, dosage, and timing of caffeine supplementation. METHODS: Six databases were searched for studies determining the effect of caffeine (except mouth rinsing) on exercise performance between CYP1A2 genotypes. Three-level meta-analyses were performed using standardized mean differences (SMD; Hedge's g) to determine the effect of caffeine on exercise outcomes within and between CYP1A2 genotypes (AA, AC, CC)...

PURPOSE: This study investigated the effect of progressively adding sets for the lower- limb every two weeks versus performing a constant set volume in resistance-trained males. METHODS: Thirty-one resistance-trained males (age 24.4 ± 2.9 years; height 175.5 ± 6.5 cm; body mass 80.1 ± 9.4 kg; body fat 14.4 ± 3.1%; resistance training [RT] experience 5.1 ± 2.2 years; one repetition maximum (1-RM) barbell back squat:body mass ratio 1.7 ± 0...

PURPOSE: Narrative reviews have suggested that post-activation induced by warm-up routines is effective to increase endurance exercise performance in real-world scenarios. However, systematic reviews with meta-analysis (SRMA) rather than narrative ones are required to provide an up-to-date summary of the evidence and provide directions for practical decisions. Therefore, we systematically reviewed peer-reviewed and gray literature to determine the certainty of evidence and the relative effects of post-activation performance enhancement (PAPE) in endurance exercises...