Physiologie Féminine, Cycle Menstruel & Adaptations Force / Endurance

The study compared changes in strength and regional muscle hypertrophy between different ranges of motion (ROM) in the knee extension exercise. Forty-five untrained women were randomized to either a control group or to perform the exercise in one of the following 4 groups (0°=extended knee): Full ROM (FULLROM: 100°-30° of knee flexion); Initial Partial ROM (INITIALROM: 100°-65°); Final Partial ROM (FINALROM: 65°-30°); Varied ROM (VARROM: daily alternation between the ROM of INITIALROM and FINALROM). Pre- and post-training assessments included one repetition maximum (1RM) testing in the ROM corresponding to the in…

Kassiano, W, Costa, B, Kunevaliki, G, Soares, D, Zacarias, G, Manske, I, Takaki, Y, Ruggiero, MF, Stavinski, N, Francsuel, J, Tricoli, I, Carneiro, MAS, and Cyrino, ES. Greater gastrocnemius muscle hypertrophy after partial range of motion training performed at long muscle lengths. J Strength Cond Res 37(9): 1746-1753, 2023-Whether there is an optimal range of motion (ROM) to induce muscle hypertrophy remains elusive, especially for gastrocnemius. This study aimed to compare the changes in gastrocnemius muscle thickness between calf raise exercise performed with full ROM (FULL ROM ), partial ROM performed in the …

The aim of the present study was to analyse the role of exercises' resistance profile in regional hypertrophy. Thirty-eight healthy women completed a 9-week resistance training program consisting of either 4 sets of 12 repetitions to volitional failure of inclined bicep curls (INC group) or preacher curls (PREA group), three times per week. Pre- and post-intervention muscle thickness was measured using B-mode ultrasound imaging with a linear-array transducer. Scan acquisition sites were determined by measuring 50%, 60% and 70% of the distance between the posterior crest of the acromion and the olecranon. Statisti…

BACKGROUND: Weekly set volume and frequency are used to manipulate resistance training dosage. Previous research has identified higher weekly set volume as enhancing muscle hypertrophy and strength gains, but the nature of the dose-response relationship still needs to be investigated. Mixed evidence exists regarding the effects of higher weekly frequency. OBJECTIVE: We aimed to explore the dose-response relationships between key resistance training dosage variables (weekly set volume and frequency) and strength and hypertrophy. METHODS: Before meta-analyzing the volume and frequency research, all contributing res…

This study examined the influence of resistance training (RT) proximity-to-failure, determined by repetitions-in-reserve (RIR), on quadriceps hypertrophy and neuromuscular fatigue. Resistance-trained males (n = 12) and females (n = 6) completed an 8-week intervention involving two RT sessions per week. Lower limbs were randomised to perform the leg press and leg extension exercises either to i) momentary muscular failure (FAIL), or ii) a perceived 2-RIR and 1-RIR, respectively (RIR). Muscle thickness of the quadriceps [rectus femoris (RF) and vastus lateralis (VL)] and acute neuromuscular fatigue (i.e., repetitio…

PURPOSE: To describe training variations across the annual cycle in Olympic and World Champion endurance athletes, and determine whether these athletes used tapering strategies in line with recommendations in the literature. METHODS: Eleven elite XC skiers and biathletes (4 male; 28±1 yr, 85±5 mL x min(-1) x kg(-1) VO2max, 7 female, 25±4 yr, 73±3 mL x min(-1) x kg(-1) VO2max) reported one year of day-to-day training leading up to the most successful competition of their career. Training data were divided into periodization and peaking phases and distributed into training forms, intensity zones and endurance activ…

OBJECTIVE: The effects of ROM manipulation on muscle strength and hypertrophy response remain understudied in long-term interventions. Thus, we compared the changes in strength and regional muscle hypertrophy after training in protocols with different ranges of motion (ROM) in the seated dumbbell preacher curl exercise using a within-participant experimental design. DESIGN AND METHODS: Nineteen young women had one arm randomly assigned to train in the initial ROM (INITIALROM: 0°-68°; 0° = extended elbow) while the contralateral arm trained in the final ROM (FINALROM: 68°-135°), three times per week over an eight-…

PURPOSE: This study assessed variability in muscle size and strength changes in a large cohort of men and women after a unilateral resistance training program in the elbow flexors. A secondary purpose was to assess sex differences in size and strength changes after training. METHODS: Five hundred eighty-five subjects (342 women, 243 men) were tested at one of eight study centers. Isometric (MVC) and dynamic strength (one-repetition maximum (1RM)) of the elbow flexor muscles of each arm and magnetic resonance imaging (MRI) of the biceps brachii (to determine cross-sectional area (CSA)) were assessed before and aft…

BACKGROUND: Progressive overload is a principle of resistance training exercise program design that typically relies on increasing load to increase neuromuscular demand to facilitate further adaptations. However, little attention has been given to another way of increasing demand-increasing the number of repetitions. OBJECTIVE: This study aimed to compare the effects of two resistance training programs: (1) increasing load while keeping repetition range constant vs (2) increasing repetitions while keeping load constant. We aimed to compare the effects of these programs on lower body muscle hypertrophy, muscle str…

Front, full, and parallel squats are some of the most popular squat variations. The purpose of this investigation was to compare mean and peak electromyography (EMG) amplitude of the upper gluteus maximus, lower gluteus maximus, biceps femoris, and vastus lateralis of front, full, and parallel squats. Thirteen healthy women (age = 28.9 ± 5.1 y; height = 164 ± 6.3 cm; body mass = 58.2 ± 6.4 kg) performed 10 repetitions of their estimated 10-repetition maximum of each respective variation. There were no statistical (P ≤ .05) differences between full, front, and parallel squats in any of the tested muscles. Given th…

We compared performing preacher and incline biceps curls on changes in elbow flexor muscle size and strength. This was a between-group repeated measure randomized trial. Sixty-three young women performed the preacher biceps curl (n=30) or the incline biceps curl (n=33) for 8 weeks, twice a week. We measured the muscle thickness of elbow flexors at the proximal, middle, and distal sites. We assessed the muscle strength using three repetition maximum tests in the preacher curl and the incline curl. We observed a greater increase in the proximal elbow flexor thickness in the incline biceps curl compared to the preac…

BACKGROUND: The effectiveness of strength training with free-weight vs. machine equipment is heavily debated. Thus, the purpose of this meta-analysis was to summarize the data on the effect of free-weight versus machine-based strength training on maximal strength, jump height and hypertrophy. METHODS: The review was conducted in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, and the systematic search of literature was conducted up to January 1st, 2023. Studies that directly compared free-weight vs. machine-based strength training for a minimum of 6 week…

BACKGROUND: Weight-training sports, including weightlifting, powerlifting, bodybuilding, strongman, Highland Games, and CrossFit, are weight-training sports that have separate divisions for males and females of a variety of ages, competitive standards, and bodyweight classes. These sports may be considered dangerous because of the heavy loads commonly used in training and competition. OBJECTIVES: Our objective was to systematically review the injury epidemiology of these weight-training sports, and, where possible, gain some insight into whether this may be affected by age, sex, competitive standard, and bodyweig…

The purpose of this study was to investigate the effects of adding heavy strength training to female duathletes' normal endurance training on both cycling and running performance. Nineteen well-trained female duathletes (VO2max cycling: 54 ± 3 ml∙kg-1∙min-1, VO2max running: 53 ± 3 ml∙kg-1∙min-1) were randomly assigned to either normal endurance training (E, n = 8) or normal endurance training combined with strength training (E+S, n = 11). The strength training consisted of four lower body exercises [3 × 4-10 repetition maximum (RM)] twice a week for 11 weeks. Running and cycling performance were assessed using 5-…

There is increasing evidence for strong genetic influences on athletic performance and for an evolutionary "trade-off" between performance traits for speed and endurance activities. We have recently demonstrated that the skeletal-muscle actin-binding protein alpha-actinin-3 is absent in 18% of healthy white individuals because of homozygosity for a common stop-codon polymorphism in the ACTN3 gene, R577X. alpha-Actinin-3 is specifically expressed in fast-twitch myofibers responsible for generating force at high velocity. The absence of a disease phenotype secondary to alpha-actinin-3 deficiency is likely due to co…

Coingestion of glucose and galactose has been shown to enhance splanchnic extraction and metabolism of ingested galactose at rest; effects during exercise are unknown. This study examined whether combined ingestion of galactose and glucose during exercise enhances exogenous galactose oxidation. Fourteen endurance-trained male and female participants [age, 27 (5) yr; V̇o2peak, 58.1 (7.0) mL·kg-1·min-1] performed cycle ergometry for 150 min at 50% peak power on four occasions, in a randomized counterbalanced manner. During exercise, they ingested beverages providing carbohydrates at rates of 0.4 g.min-1 galactose (…

Thirty-four untrained women participated in a 6-week program to investigate slow-speed versus "normal" speed resistance-training protocols. Subjects were divided into: slow-speed (SS), normal-speed/traditional-strength (TS), normal-speed/traditional muscular endurance (TE), and non-exercising control (C) groups. Leg press, squats, and knee extensions were performed 2 days/week for the first week and 3 days/week for the remaining 5 weeks (~2 min rest). The SS group performed 6-10 repetitions maximum (6-10RM) for each set with 10 s concentric (con) and 4 s eccentric (ecc) contractions. The TS and TE groups performe…

Creatine is one of the most popular nutritional ergogenic aids for athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. In addition to athletic and exercise improvement, research has shown that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection. Additionally, a number of clinical applications of creatine suppl…

PURPOSE: To evaluate the impact of the COVID-19 pandemic on Canadian intensive care unit (ICU) workers. METHODS: Between June and August 2020, we distributed a cross-sectional online survey of ICU workers evaluating the impact of the pandemic, coping strategies, symptoms of post-traumatic stress disorder (PTSD; Impact of Events Scale-Revised), and psychological distress, anxiety, and depression (Kessler Psychological Distress Scale). We performed regression analyses to determine the predictors of psychological symptoms. RESULTS: We analyzed responses from 455 ICU workers (80% women; 67% from Ontario; 279 nurses, …

Schwanbeck, SR, Cornish, SM, Barss, T, and Chilibeck, PD. Effects of training with free weights versus machines on muscle mass, strength, free testosterone, and free cortisol levels. J Strength Cond Res 34(7): 1851-1859, 2020-Free weights offer a more unstable training environment, which enhances muscle recruitment, whereas some machines have the advantage of using a "cam" pulley system that better matches strength curves. We compared the effect of training with free weights vs. machines on muscle mass, strength, free testosterone, and free cortisol concentrations. Forty-six subjects (26 women; 22 ± 3 years) were…

Based on the important role of interleukin-15 (IL-15) in human metabolism and, in consequence, in body composition modulation, we examined whether rs1589241 and rs1057972 polymorphisms, analyzed individually or in combination, would influence the effects of a training program. Accordingly, we studied the allele and genotype distribution in a group of 163 young nonobese Caucasian women measured for selected body mass and composition, as well as biochemical parameters before and after the completion of a 12-week endurance training program. After a week-long familiarization stage, low-high impact aerobics were condu…

It has been reported that repetitive execution of a stimulus-response compatibility (SRC) task attenuates the interference effect of a choice reaction time task, known as a Simon task. We investigated whether attentional control, enhanced by repetitive execution of an SRC task, would reduce the interference effect of a Simon task and could be transferred to lacrosse shooting skills, increasing the likelihood that players would shoot in the direction opposite to the goalie's initial movement. Female lacrosse players who were matched in terms of age, handedness score, competitive lacrosse playing experience, and pl…

Contest decisions are influenced by the outcomes of recent fights (winner-loser effects). Steroid hormones and serotonin are closely associated with aggression and therefore probably also play important roles in mediating winner-loser effects. In mangrove rivulus fish, Kryptolebias marmoratus, individuals with higher testosterone (T), 11-ketotestosterone and cortisol levels are more capable of winning, but titres of these hormones do not directly mediate winner-loser effects. In this study, we investigated the effects of winning/losing experiences on brain expression levels of the receptor genes for androgen (AR)…

An essential exercise for strength training of the lower limbs is the squat exercise. During this exercise, changes in lumbar lordosis are commonly used to indicate when the descent of the squat should cease, yet the behavior of the lumbar-scarum segments remains unclear. The purpose of this study was to quantify the lumbar-sacrum movements during the back squat, because the movement of the sacrum is influenced by the width of stance, this variable was also investigated. Thirty trained subjects, 18 men with 1 repetition maximum (1RM) squat of 123% (13.9%) of bodyweight and 12 women with 1RM squat of 93% (15.6%), …

OBJECTIVE: To demonstrate the response to a proprioceptive training model during a 1-week rehabilitation regime. The techniques were demonstrated on a college-aged female basketball player who had injured her anterior cruciate ligament (ACL) several weeks earlier. The athlete was tested, trained, and then retested during her semester break. BACKGROUND: The ACL injury has become a fairly common occurrence in the world of athletics. Knowing this, the athletic trainer is constantly searching for ways to improve the rehabilitative process. New research demonstrates that rehabilitation should be based on proprioceptio…

PURPOSE: To study the degree of accuracy in gingival shade matching of undergraduate students using a computer application. MATERIALS AND METHODS: In total, 76 undergraduate dental students' gingival shade selection abilities were evaluated using an in-house developed computer application. A total of 15 intraoral gingival photographs and 21 pink gingival color porcelain samples were used. The environmental conditions were standardized, and no time limit was set for answering in the computer application. RESULTS: Fourteen gingival color samples (66.6%) were not useful for representing the studied gingival shades. …

Muscular strength and hypertrophy following resistance training may be obtained in different degrees depending on the approach performed. This study was designed to compare the responses of the biceps brachii to two preacher curl exercises, one performed on a cable-pulley system (CAB; in which a greater torque was applied during the exercise when elbows were flexed and biceps shortened) and one performed with a barbell (BAR; in which greater torque was applied when the elbows were extended and biceps stretched). Thirty-five young adults (CAB: 13 men, 5 women; BAR: 12 men, 5 women; age = 24 ± 5 years) performed a …

The loss of muscle mass and strength with aging results in significant functional impairment. Creatine supplementation has been used in combination with resistance training as a strategy for increasing lean tissue mass and muscle strength in older adults, but results across studies are equivocal. We conducted a systematic review and meta-analysis of randomized controlled trials of creatine supplementation during resistance training in older adults with lean tissue mass, chest press strength, and leg press strength as outcomes by searching PubMed and SPORTDiscus databases. Twenty-two studies were included in our m…

This study investigated the effects of a 10-week resistance training to failure on neuromuscular adaptations in young women. Eighty-nine active young women were randomly assigned to one of three groups: 1) repetitions to failure (RF; three sets of repetitions to failure); 2) repetitions not to failure with equalized volume (RNFV; four sets of 7 repetitions); and 3) repetitions not to failure (RNF; three sets of 7 repetitions). All groups performed the elbow flexor exercise (bilateral biceps curl) and trained 2 days per week using 70% of 1RM. There were significant increases (p<0.05) in muscle strength after 5 (15…

The back squat and barbell hip thrust are both popular exercises used to target the lower body musculature; however, these exercises have yet to be compared. Therefore, the purpose of this study was to compare the surface electromyographic (EMG) activity of the upper and lower gluteus maximus, biceps femoris, and vastus lateralis between the back squat and barbell hip thrust. Thirteen trained women (n = 13; age = 28.9 years; height = 164 cm; mass = 58.2 kg) performed estimated 10-repetition maximums (RM) in the back squat and barbell hip thrust. The barbell hip thrust elicited significantly greater mean (69.5% vs…

Despite little objective support, heel-raise exercises are commonly performed using varying foot positions in an attempt to alter medial (MG) and lateral (LG) gastrocnemius involvement. This investigation compared MG and LG activation during the concentric phase (CP) and eccentric phase (EP) of the heel-raise exercise using neutral (NE), internally rotated (IR), and externally rotated (ER) foot positions. Twenty healthy subjects (10 men, 10 women; age = 23.7 ± 3.1 years) with resistance training experience performed free-weight (130-135% body mass) heel-raise exercise on a 3.81-cm block. Surface electromyography …

We compared the effects of a 6-day high-intensity interval training (HIT) microcycle followed by a 5-day active recovery period (HITblock) with a time-matched period of continued regular training (REG) on endurance performance in well-trained female cross-country skiers and biathletes. Seventeen athletes (maximal oxygen consumption ( V ˙ O 2 max ): 55.1 (5.2) mL·min-1 kg-1) were assigned to either HITblock or REG. No differences in training volume or intensity were observed between the groups during the 4 weeks preceding the intervention. During the intervention, HITblock completed five HIT sessions over 6 days (…

INTRODUCTION: This study compared the effects of dumbbell versus cable lateral raises on lateral deltoid muscle thickness (MT) in resistance-trained men and women, with shoulder adduction/abduction range of motion standardised and matched between conditions. METHODS: Twenty-four participants completed an eightweek intervention comprising two weekly resistance training sessions of five sets of lateral raises completed to momentary failure. The study employed a within-participant design with each participant's arms randomly allocated to the cable or dumbbell lateral raise. MT of the proximal and distal lateral delt…

We use a unique platform called the Open Dynamic Interaction Network (ODIN) app, to collect fine grained, daily data from participants. Our results graphically depict the feasibility of using the ODIN app with people who use drugs (PWUD) in the Great Plains. During fall 2022-spring 2023, 100 participants (53% female), using an Android smartphone with the ODIN app installed, were asked up to 22 questions per day on substance use, stress, and social support over 30 days. The mean overall daily response rates to the ecological momentary assessment questions using the ODIN app was 82%. Overall, 82% of participants re…

The aim of this study was to compare the effects of progressive overload in resistance training on muscle strength and cross-sectional area (CSA) by specifically comparing the impact of increasing load (LOADprog) versus an increase in repetitions (REPSprog). We used a within-subject experimental design in which 39 previously untrained young persons (20 men and 19 women) had their legs randomized to LOADprog and REPSprog. Outcomes were assessed before and after 10 weeks of training. Muscle strength was assessed using the one repetition maximum (1RM) test on the leg extension exercise, and the CSA of the vastus lat…

RESEARCH QUESTION: Is race/ethnicity or access to care, as defined by insurance coverage, distance to the clinic and zip code (postal code), associated with care discontinuation following IVF? DESIGN: A retrospective cohort study of 878 diverse women who underwent 1571 IVF cycles from 2014 to 2018 at a Southeastern academic medical centre was performed. Women were divided into low (LAC) and high (HAC) access to care groups. HAC was defined as possessing IVF insurance coverage, living ≤25 miles from the clinic, and living in a zip code with a median income ≥$75,000. Access groups and racial/ethnic groups were comp…

Anterior cruciate ligament injuries are a prominent issue in the field of sports medicine, especially for the female athlete. Extensive research has been performed that acknowledges the disparity in anterior cruciate ligament injury rates between male and female athletes and the high prevalence of risk factors specific to females. The underlying causes of anterior cruciate ligament injuries are widespread and are important to consider when approaching injury prevention. For example, prevention techniques aim to correct neuromuscular imbalances and improve biomechanical deficits, which are some of the most signifi…

AIM: This study characterised the decoupling of internal-to-external workload in marathon running and investigated whether decoupling magnitude and onset could improve predictions of marathon performance. METHODS: The decoupling of internal-to-external workload was calculated in 82,303 marathon runners (13,125 female). Internal workload was determined as a percentage of maximum heart rate, and external workload as speed relative to estimated critical speed (CS). Decoupling magnitude (i.e., decoupling in the 35-40 km segment relative to the 5-10 km segment) was classified as low (< 1.1), moderate (≥ 1.1 but < 1.2)…

BACKGROUND: Athletes maintain a balance between stress and recovery and adopt recovery modalities that manage fatigue and enhance recovery and performance. Optimal TST is subject to individual variance. However, 7-9 h sleep is recommended for adults, while elite athletes may require more quality sleep than non-athletes. METHODS: A total of 338 (elite n = 115, 74 males and 41 females, aged 23.44 ± 4.91 years; and sub-elite n = 223, 129 males and 94 females aged 25.71 ± 6.27) athletes were recruited from a variety of team and individual sports to complete a battery of previously validated and reliable widely used q…

Simultaneous kidney-pancreas transplantation can successfully restore fertility in women with type 1 diabetes mellitus and kidney failure. There have been few cases of pregnancy after simultaneous kidney-pancreas transplantation, and a second pregnancy is rare. We report a case of two live births in rapid succession in a simultaneous kidney-pancreas transplantation recipient, complicated by pre-eclampsia but with excellent fetal and graft outcomes. The first pregnancy was achieved with IVF, while the second was achieved naturally. Simultaneous kidney-pancreas transplantation with stable pre-pregnancy graft functi…

The purpose of this study was to investigate the effect of adding heavy strength training to well-trained female cyclists' normal endurance training on cycling performance. Nineteen female cyclists were randomly assigned to 11 weeks of either normal endurance training combined with heavy strength training (E+S, n = 11) or to normal endurance training only (E, n = 8). E+S increased one repetition maximum in one-legged leg press and quadriceps muscle cross-sectional area (CSA) more than E (P < 0.05), and improved mean power output in a 40-min all-out trial, fractional utilization of VO2 max and cycling economy (P <…

STUDY DESIGN: Evaluation of a new quantitative imaging technique in a prospective study design. OBJECTIVE: To assess glycosaminoglycan (GAG) content of lumbar intervertebral discs (IVDs) in healthy volunteers with chemical exchange saturation transfer (CEST). SUMMARY OF BACKGROUND DATA: Biochemical alterations of lumbar discs are present before the appearance of morphological changes. GAG loss plays a central role in these degenerative processes. METHODS: Lumbar intervertebral discs of healthy controls (26 women, 22 men; mean age 31 ± 8 years; range: 21-49 years) without lumbar back pain were examined at a 3 Tesl…

We aimed to compare site-specific bone mineral densities (BMDs) between adolescent endurance runners and sprinters and examine the relationship of fat-free mass (FFM) and nutrient intake on BMD. In this cross-sectional study, 37 adolescent female endurance runners and sprinters (16.1 ± 0.8 years) were recruited. BMD and FFM were assessed by dual-energy X-ray absorptiometry. Nutrient intake and menstrual state were evaluated by questionnaires. After adjusting for covariates, spine and total bone less head (TBLH) BMDs were significantly higher in sprinters than endurance runners (TBLH, 1.02 ± 0.05 vs. 0.98 ± 0.06 g…

INTRODUCTION: Exercise, and in particular balance and coordination related activities such as dance, appear to have positive effects on cognitive function, as well as neurodegenerative conditions such as dementia and Parkinson's disease. Quadrupedal gait training is a movement system requiring coordination of all four limbs that has previously been associated with cognitive development in children. There is currently little research into the effect of complex QDP movements on cognitive function in adults. PURPOSE: To determine the effects of a novel four-week quadrupedal gait training programme on markers of cogn…

BACKGROUND: The consumption of a high protein diet (>4 g/kg/d) in trained men and women who did not alter their exercise program has been previously shown to have no significant effect on body composition. Thus, the purpose of this investigation was to determine if a high protein diet in conjunction with a periodized heavy resistance training program would affect indices of body composition, performance and health. METHODS: Forty-eight healthy resistance-trained men and women completed this study (mean ± SD; Normal Protein group [NP n = 17, four female and 13 male]: 24.8 ± 6.9 yr; 174.0 ± 9.5 cm height; 74.7 ± 9.…

It has been hypothesized that performing aerobic exercise after an overnight fast accelerates the loss of body fat. The purpose of this study was to investigate changes in fat mass and fat-free mass following four weeks of volume-equated fasted versus fed aerobic exercise in young women adhering to a hypocaloric diet. Twenty healthy young female volunteers were randomly assigned to 1 of 2 experimental groups: a fasted training (FASTED) group that performed exercise after an overnight fast (n = 10) or a post-prandial training (FED) group that consumed a meal prior to exercise (n = 10). Training consisted of 1 hour…

Exhaustive resistance training programs that have been previously referred to as extreme conditioning protocols have increased in popularity in military and civilian populations in recent years. However, because of their highly fatiguing nature, proprioception is likely altered during such programs that would significantly affect the safety and efficacy of such programs. Therefore, the purpose of this study was to assess the alterations in movement patterns that result from extreme conditioning protocols and to evaluate if these protocols can be deemed safe and effective. Twelve men (age 24 ± 4.2 years, height 17…

BACKGROUND: Current approaches to diagnosing testosterone deficiency do not consider the physiological consequences of various testosterone levels or whether deficiencies of testosterone, estradiol, or both account for clinical manifestations. METHODS: We provided 198 healthy men 20 to 50 years of age with goserelin acetate (to suppress endogenous testosterone and estradiol) and randomly assigned them to receive a placebo gel or 1.25 g, 2.5 g, 5 g, or 10 g of testosterone gel daily for 16 weeks. Another 202 healthy men received goserelin acetate, placebo gel or testosterone gel, and anastrozole (to suppress the c…

Endurance exercise training studies frequently show modest changes in VO2max with training and very limited responses in some subjects. By contrast, studies using interval training (IT) or combined IT and continuous training (CT) have reported mean increases in VO2max of up to ~1.0 L · min(-1). This raises questions about the role of exercise intensity and the trainability of VO2max. To address this topic we analyzed IT and IT/CT studies published in English from 1965-2012. Inclusion criteria were: 1)≥ 3 healthy sedentary/recreationally active humans <45 yrs old, 2) training duration 6-13 weeks, 3) ≥ 3 days/week,…

Lifestyle interventions for weight loss are the cornerstone of obesity therapy, yet their optimal design is debated. This is particularly true for postmenopausal women; a population with a high prevalence of obesity yet toward whom fewer studies are targeted. We conducted a year-long, 4-arm randomized trial among 439 overweight-to-obese postmenopausal sedentary women to determine the effects of a calorie-reduced, low-fat diet (D), a moderate-intensity, facility-based aerobic exercise program (E), or the combination of both interventions (D+E), vs. a no-lifestyle-change control (C) on change in body weight and com…

UNLABELLED: Repeated maximal-intensity short-duration exercise (sprint interval training, SIT) can produce muscle adaptations similar to endurance training (ET) despite a much reduced training volume. However, most SIT data use cycling, and little is known about its effects on body composition or maximal cardiac output (Qmax). PURPOSE: The purpose of this study was to assess body composition, 2000-m run time trial, VO(2max), and Q(max) effects of run SIT versus ET. METHODS: Men and women (n = 10 per group; mean ± SD: age = 24 ± 3 yr) trained three times per week for 6 wk with SIT, 30-s all-out run sprints (manual…

Wearing high heels (HH) places the calf muscle-tendon unit (MTU) in a shortened position. As muscles and tendons are highly malleable tissues, chronic use of HH might induce structural and functional changes in the calf MTU. To test this hypothesis, 11 women regularly wearing HH and a control group of 9 women were recruited. Gastrocnemius medialis (GM) fascicle length, pennation angle and physiological cross-sectional area (PCSA), the Achilles' tendon (AT) length, cross-sectional area (CSA) and mechanical properties, and the plantarflexion torque-angle and torque-velocity relationships were assessed in both group…

We evaluated the effects of concurrent strength and aerobic endurance training on muscle strength and endurance, body composition, and flexibility in female college athletes and compared two concurrent exercise (CE) protocols. Twenty-eight women (mean age, 19.6 years) were divided into two matched groups and evaluated before and after a vigorous, 11-week, 3-days per week CE training program. One group did serial CE consisting of a warm-up, resistance exercises at low heart rate (HR), aerobics, and a range of motion cool down. The other group did integrated CE consisting of aerobics, the same resistance exercises …

The injury epidemiology of competitive power lifters was investigated to provide a basis for injury prevention initiatives in power lifting. Self-reported retrospective injury data for 1 year and selected biographical and training information were obtained via a 4-page injury survey from 82 men and 19 women of varying ages (Open and Masters), body masses (lightweight and heavyweight), and competitive standards (national and international). Injury was defined as any physical damage to the body that caused the lifter to miss or modify one or more training sessions or miss a competition. A total of 118 injuries, whi…

This study investigated variations in electromyographic (EMG) responses of the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) due to foot position during leg extension. Twenty-four men and women (23.67 +/= 4.02 years) performed 8 repetitions at 70% of 8 repetition maximum with their leg medially rotated, laterally rotated, and neutral. Repeated-measures analyses of variance indicated that the highest normalized root mean square (NrmsEMG) for the VM and VL occurred with medial rotation, and the highest NrmsEMG for the RF occurred with lateral rotation. Significant NrmsEMG increases and median…

PURPOSE: To compare the physiological and performance adaptations between periodized and nonperiodized resistance training in women collegiate tennis athletes. METHODS: Thirty women (19 +/- 1 yr) were assigned to either a periodized resistance training group (P), nonperiodized training group (NV), or a control group (C). Assessments for body composition, anaerobic power, VO2(max), speed, agility, maximal strength, jump height, tennis-service velocity, and resting serum hormonal concentrations were performed before and after 4, 6, and 9 months of resistance training performed 2-3 d.wk (-1). RESULTS: Nine months of…

BACKGROUND AND PURPOSE: Frequency and duration of static stretching have not been extensively examined. Additionally, the effect of multiple stretches per day has not been evaluated. The purpose of this study was to determine the optimal time and frequency of static stretching to increase flexibility of the hamstring muscles, as measured by knee extension range of motion (ROM). SUBJECTS: Ninety-three subjects (61 men, 32 women) ranging in age from 21 to 39 years and who had limited hamstring muscle flexibility were randomly assigned to one of five groups. The four stretching groups stretched 5 days per week for 6…

The purpose of this experiment was to investigate the individual differences and the specificity in the response of maximal aerobic power (MAP) and capacity (MAC) to a 20-week aerobic training program. Twenty-four subjects (25 +/- 4 years), ascertained as sedentary, including 13 women and 11 men, participated in this study. MAP was determined with a progressive maximal ergocycle test, while MAC was computed as the total work output accomplished during a 90-min maximal ergocycle test. A modified bicycle ergometer allowed the exact measurement of the distance and the load for the computation of the work performed d…

In brief: This retrospective survey of the clinical records of 1,650 patients seen from 1978 to 1980 identified 1,819 injuries. Almost 60% of the patients were men, but women under age 30 had the greatest risk of overuse running injuries. The knee was the most commonly injured site, and patellofemoral pain syndrome was the most common injury. Most patients had moderate to severe degrees of varus alignment and subsequent overpronation. Because certain injuries were more frequent in one sex or the other, the authors say future studies should differentiate injuries by sex.

Position Statement: The International Society of Sports Nutrition (ISSN) bases the following position stand on a critical analysis of the literature regarding the effects of diet types (macronutrient composition; eating styles) and their influence on body composition. The ISSN has concluded the following. 1) There is a multitude of diet types and eating styles, whereby numerous subtypes fall under each major dietary archetype. 2) All body composition assessment methods have strengths and limitations. 3) Diets primarily focused on fat loss are driven by a sustained caloric deficit. The higher the baseline body fat…

This study compared calf training with initial partial repetitions versus full range-of-motion (ROM) repetitions followed by past-failure partials on gastrocnemius hypertrophy. Twenty-three participants (men: n = 16 and women: n = 7) performed four sets of unilateral Smith machine calf raises to momentary failure twice a week for 8 weeks. One leg was trained using initial partials to their individualized maximum dorsiflexion ROM. The contralateral leg was trained with a full ROM and continued with past-failure partials after failure in peak plantarflexion. Medial gastrocnemius muscle thickness was measured with u…

We compared the effects of different weekly calf training sets on muscle size changes. Sixty-one untrained young women performed a calf training program for 6 weeks, 3 d·wk-1, with differences in resistance training volume. The participants were randomly assigned to one of the three groups: 6-SET, 9-SET, and 12-SET weekly calf training sets. The calf raise exercise was performed in sets of 15-20 repetitions maximum. The muscle thickness measurements of medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (SOL) were taken via B-mode ultrasound. We used the sum of the three-muscle thickness as a proxy …

INTRODUCTION: Several retrospective studies of strength sport athletes have reported strength adaptations over months to years; however, such adaptations are not linear. METHODS: We explored changes in strength over time in a large, retrospective sample of powerlifting (PL) athletes. Specifically, we examined the rate and magnitude of strength adaptation based on age category and weight class for PL competition total, and the squat, bench press, and deadlift, respectively. Mixed effects growth modelling was performed for each operationalised performance outcome (squat, bench press, deadlift, and total) as the dep…

BACKGROUND: Anorexia nervosa (AN) is characterized by low body weight, disturbed eating, body image disturbance, anxiety, and interoceptive dysfunction. However, the neural processes underlying these dysfunctions in AN are unclear. This investigation combined an interoceptive pharmacological probe, the peripheral β-adrenergic agonist isoproterenol, with resting-state functional magnetic resonance imaging to examine whether individuals with AN relative to healthy comparison participants show dysregulated neural coupling in central autonomic network brain regions. METHODS: Resting-state functional magnetic resonanc…

Previously trained mouse muscles acquire strength and volume faster than naïve muscles; it has been suggested that this is related to increased myonuclear density. The present study aimed to determine whether a previously strength-trained leg (mem-leg) would respond better to a period of strength training than a previously untrained leg (con-leg). Nine men and 10 women performed unilateral strength training (T1) for 10 wk, followed by 20 wk of detraining (DT) and a 5-wk bilateral retraining period (T2). Muscle biopsies were taken before and after each training period and analyzed for myonuclear number, fiber volu…

BACKGROUND: The present study tested the possibility of a localized fat mass (FM) reduction by means of training programmes focusing on specific bodily regions. METHODS: Sixteen physically inactive women (age: 31±4; BMI: 27.5±2.1), randomly allocated to two groups, completed an 8 week training programme. In one group (UpBdResist) training sessions consisted of upper body resistance exercises followed by 30-minute cycling at 50%VO2max, while the other group (LwBdResist) performed lower body resistance exercises followed by 30 minutes on an arm-ergometer. Regional body composition was assessed by DEXA and skin fold…

Objectives To evaluate the existing evidence for associations between coffee consumption and multiple health outcomes.Design Umbrella review of the evidence across meta-analyses of observational and interventional studies of coffee consumption and any health outcome.Data sources PubMed, Embase, CINAHL, Cochrane Database of Systematic Reviews, and screening of references.Eligibility criteria for selecting studies Meta-analyses of both observational and interventional studies that examined the associations between coffee consumption and any health outcome in any adult population in all countries and all settings. S…

Creatine is one of the most popular nutritional ergogenic aids for athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. In addition to athletic and exercise improvement, research has shown that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection. Additionally, a number of clinical applications of creatine suppl…

Bridging exercise variations are well researched and commonly employed for both rehabilitation and sport performance. However, resisted bridge exercise variations have not yet been compared in a controlled experimental study. Therefore, the purpose of this study was to compare the differences in upper and lower gluteus maximus, biceps femoris, and vastus lateralis electromyography (EMG) amplitude for the barbell, band, and American hip thrust variations. Thirteen healthy female subjects (age = 28.9 y; height = 164.3 cm; body mass = 58.2 kg) familiar with the hip thrust performed 10 repetitions of their 10-repetit…

The purpose of this study was to examine the effects of a localized muscle endurance resistance training program on total body and regional tissue composition. Seven men and 4 women (aged 23 ± 1 years) were trained with their nondominant leg during 12 weeks, 3 sessions per week. Each session consisted of 1 set of 960-1,200 repetitions (leg press exercise), at 10-30% 1 repetition maximum. Before and after training, body mass, bone mass, bone mineral density (BMD), lean mass, fat mass, and fat percentage were determined by dual-emission x-ray absorptiometry. Energy intakes were registered using a food recall questi…

STUDY DESIGN: Randomized controlled trial. OBJECTIVE: To compare the effects of full range of motion (ROM) and limited ROM isolated lumbar extension exercise upon full ROM lumbar extension strength, ROM, perceived pain, and disability. SUMMARY OF BACKGROUND DATA: Limited ROM is common in chronic low back pain as is lumbar extensor deconditioning. Limited ROM exercise is a common prescription but is yet to be empirically tested. METHODS: Males (n = 21) and females (n = 17) with nonspecific chronic low back pain were initially recruited. Participants were randomized to either a full ROM (FullROM) or limited ROM (Li…

The efficacy of caffeine ingestion in enhancing aerobic performance is well established. However, despite suggestions that caffeine may enhance resistance exercise performance, research is equivocal on the effect of acute caffeine ingestion on resistance exercise performance. It has also been suggested that dampened perception of perceived exertion and pain perception might be an explanation for any possible enhancement of resistance exercise performance due to caffeine ingestion. Therefore, the aim of this study was to examine the acute effect of caffeine ingestion on repetitions to failure, rating of perceived …

PURPOSE: The purpose of this study was to evaluate differences in hamstring activation during lower body resistance training exercises. This study also sought to assess differences in hamstring-to-quadriceps muscle activation ratios and gender differences therein. METHODS: A randomized repeated measures design was used to compare six resistance training exercises that are commonly believed to train the hamstrings, including the squat, seated leg curl, stiff leg dead lift, single leg stiff leg dead lift, good morning, and Russian curl. Subjects included 34 college athletes. Outcome measures included the biceps fem…

The purpose of this study was to examine the effectiveness of a commercial abdominal machine (Ab-Slide) and three common abdominal strengthening exercises (abdominal crunch, supine double leg thrust, and side bridge) on activating abdominal and minimizing extraneous (nonabdominal) musculature-namely, the rectus femoris muscle. We recruited 10 males and 12 females whose mean (+/- SD) percent body fat was 10.7 +/- 4 and 20.7% +/- 3.2%, respectively. Electromyographic (EMG) data were recorded using surface electrodes for the rectus abdominis, external oblique, internal oblique, and rectus femoris. We recorded peak E…

PURPOSE: It is believed spot reduction, the exercise-induced localized loss of subcutaneous fat, does not occur as a result of an exercise program; however, evidence as a whole has been inconsistent. To reexamine this concept, we compared subcutaneous fat measurements before and after resistance training among 104 subjects (45 men, 59 women). METHODS: Subjects participated in 12 wk of supervised resistance training of their nondominant arm. Magnetic resonance imaging and skinfold calipers examined subcutaneous fat in the nondominant (trained) and dominant (untrained) arms before and after resistance training. Rep…

Muscle force-generating properties are often derived from cadaveric studies of muscle architecture. While the relative sizes of muscles at a single upper limb joint have been established in cadaveric specimens, the relative sizes of muscles across upper limb joints in living subjects remain unclear. We used magnetic resonance imaging to measure the volumes of the 32 upper limb muscles crossing the glenohumeral joint, elbow, forearm, and wrist in 10 young, healthy subjects, ranging from a 20th percentile female to a 97th percentile male, based on height. We measured the volume and volume fraction of these muscles.…

The magnitude of failure in voluntary drive after fatiguing contractions of different intensities in men and women is not known. The purpose of this study was to compare the time to task failure and voluntary activation of men and women for a sustained isometric contraction performed at a low and high intensity with the elbow flexor muscles. Nine men and nine women sustained an isometric contraction at 20% and 80% of maximal voluntary contraction (MVC) force until task failure during separate sessions. The men had a shorter time to failure than women for the 20% but not the 80% MVC task. Voluntary activation was …

Prestigious professional organisations have questioned the efficacy of resistive training by children or have often neglected to address weightlifting in their position papers on resistive training for children. The purpose of this paper was to address the deficit in data regarding the efficacy of training children for weightlifting and to report data regarding to safety in this population. Eleven subjects (3 female, 8 male) who had trained at the USA Weightlifting Development Centre in Shreveport Louisiana for a minimum of 22 months (mean = 28.8; SD +/- 4.4) served as subjects for this study. Means for the pool …

STUDY DESIGN: Repeated measures analysis of joint angle effects on hip and knee muscle electromyographic (EMG) activity. OBJECTIVES: To simultaneously determine angle-dependent changes in maximal voluntary isometric contraction (MVIC) torque and EMG activity during hip extension and knee flexion. BACKGROUND: Procedures for normalizing EMG data and for determining torque-angle relationships for various joint motions both entail asking subjects to exert an MVIC. The implicit assumption in these paradigms is that magnitude of the EMG response is at a constant, maximum level so that observed angle-dependent variation…