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The aim of the present investigation was to determine whether a 1-h floatation-restricted environmental stimulation therapy (floatation-REST) session could augment recovery from high-intensity resistance exercise (6 × 10 back squats, 2-min rest) known to induce significant metabolic, adrenergic, and mechanical stress.Eleven healthy resistance-trained males (age, 22.5 ± 2.3 yr; height, 176.4 ± 6.0 cm; weight, 85.7 ± 6.2 kg; back squat one-repetition maximum, 153.1 ± 20.1 kg; strength-to-weight ratio, 1.8 ± 0.2) completed the within-subject, crossover controlled study design. Participants completed two exercise testing blocks separated by a 2-wk washout. In one block, the high-intensity resistance exercise protocol was followed by a 1-h floatation-REST session, whereas recovery in the alternate block consisted of a passive sensory-stimulating control. Markers of metabolic stress, neuroendocrine signaling, structural damage, inflammation, and perceptions of soreness, mood state, and fatigue were assessed over a 48-h recovery window.Floatation-REST significantly attenuated muscle soreness across recovery ( P = 0.035) with greatest treatment difference immediately after the intervention ( P = 0.002, effect size (ES) = 1.3). Significant differences in norepinephrine ( P = 0.028, ES = 0.81) and testosterone ( P = 0.028, ES = 0.81) immediately after treatment revealed the modification of neuroendocrine signaling pathways, which were accompanied by greater improvements in mood disturbance ( P = 0.029, ES = 0.81) and fatigue ( P = 0.001, ES = 1.04).Because no adverse effects and significant and meaningful benefits were observed, floatation-REST may prove a valuable intervention for managing soreness and enhancing performance readiness after exercise.

The 2020 Dudrick Research Symposium, entitled "Expanding the Boundaries of Cancer Care Through Nutritional Support" was held on March 30, 2020, at the American Society for Parenteral and Enteral Nutrition (ASPEN), 2020 Nutrition Science & Practice Conference, it was scheduled to take place in Tampa, Florida but had to be held virtually due to the COVID-19 pandemic. The Dudrick Symposium honors the many pivotal and innovative contributions to the development and advancement of parenteral nutrition (PN) made by the late Dr. Stanley J. Dudrick, physician scientist, academic leader, and a founding member of ASPEN. This year, in addition to honor his legacy, we honored his life as we had to endure his loss in the beginning of 2020. As the 2019 recipient of the Dudrick Research Scholar Award, Dr. Jose M Pimiento organized and chaired the symposium. The presentations focused on discussing the history and the present and the future frontiers in the overlapping fields of nutritional support and cancer care. The late Dr. John Daly opened the presentation with a very moving tribute to Dr. Dudrick's life and then spoke about the impact of nutritional support on surgical care and oncologic outcomes for cancer patients. Dr. Pimiento discussed the role of nutraceuticals for cancer chemoprevention, focusing on discussing the level one clinical evidence surrounding this topic. Dr. Kraemer, explored the role of exercise physiology in cancer care for optimal nutrient utilization and the overlap between targeted physical activity and nutritional support to obtain better outcomes on the cancer population. The symposium was closed by Dr. Stephen Hursting who discussed the preclinical and clinical evidence on the impact of obesity in the soaring cancer rates and its relationship with clinical outcomes. In this paper, we cover the presentations by Drs Pimiento and Kraemer. This article is protected by copyright. All rights reserved.

The purpose of the present study was to examine the influence of an acute bout of high-intensity resistance exercise on measures of cognitive function. Ten men (Mean ± SD: age = 24.4 ± 3.2 yrs; body mass = 85.7 ± 11.8 kg; height = 1.78 ± 0.08 m; 1 repetition maximum (1RM) = 139.0 ± 24.1 kg) gave informed consent and performed a high-intensity 6 sets of 10 repetitions of barbell back squat exercise at 80% 1RM with 2 minutes rest between sets. The Automated Neuropsychological Assessment Metrics (ANAM) was completed to assess various cognitive domains during the familiarization period, immediately before, and immediately after the high-intensity resistance exercise bout. The repeated measures ANOVAs for throughput scores (r·m-1) demonstrated significant mean differences for the Mathematical Processing task (MTH; p < 0.001, η2p = 0.625) where post hoc pairwise comparisons demonstrated that the post-fatigue throughput (32.0 ± 8.8 r·m-1) was significantly greater than the pre-fatigue (23.8 ± 7.4 r·m-1, p = 0.003, d = 1.01) and the familiarization throughput (26.4 ± 5.3 r·m-1, p = 0.024, d = 0.77). The Coded Substitution-Delay task also demonstrated significant mean differences (CDD; p = 0.027, η2p = 0.394) with post hoc pairwise comparisons demonstrating that the post-fatigue throughput (49.3 ± 14.4 r·m-1) was significantly less than the pre-fatigue throughput (63.2 ± 9.6 r·m-1, p = 0.011, d = 1.14). The repeated measures ANOVAs for reaction time (ms) demonstrated significant mean differences for MTH (p < 0.001, η2p = 0.624) where post hoc pairwise comparisons demonstrated that the post-fatigue reaction time (1885.2 ± 582.8 ms) was significantly less than the pre-fatigue (2518.2 ± 884.8 ms, p = 0.005, d = 0.85) and familiarization (2253.7 ± 567.6 ms, p = 0.009, d = 0.64) reaction times. The Go/No-Go task demonstrated significant mean differences (GNG; p = 0.031, η2p = 0.320) with post hoc pairwise comparisons demonstrating that the post-fatigue (285.9 ± 16.3 ms) was significantly less than the pre-fatigue (298.5 ± 12.1 ms, p = 0.006, d = 0.88) reaction times. High-intensity resistance exercise may elicit domain-specific influences on cognitive function, characterized by the facilitation of simple cognitive tasks and impairments of complex cognitive tasks. Key points High-intensity squat resistance exercise may elicit domain-specific influences on cognitive function. Tasks associated with information processing and response inhibition was exhibited improvement for simple cognitive tasks. Complex cognitive associated with memory and recall exhibited decrements and impairments following the high-intensity back squat protocol. Understanding changes in cognition under extreme physical stress is important for interpretation of physiological influences.

This consensus statement is an update of the 1987 American College of Sports Medicine (ACSM) position stand on the use of anabolic-androgenic steroids (AAS). Substantial data have been collected since the previous position stand, and AAS use patterns have changed significantly. The ACSM acknowledges that lawful and ethical therapeutic use of AAS is now an accepted mainstream treatment for several clinical disorders; however, there is increased recognition that AAS are commonly used illicitly to enhance performance and appearance in several segments of the population, including competitive athletes. The illicit use of AAS by competitive athletes is contrary to the rules and ethics of many sport governing bodies. Thus, the ACSM deplores the illicit use of AAS for athletic and recreational purposes. This consensus statement provides a brief history of AAS use, an update on the science of how we now understand AAS to be working metabolically/biochemically, potential side effects, the prevalence of use among athletes, and the use of AAS in clinical scenarios.

This investigation examined the influence of 12-week ballistic resistance training programs on the IGF-I system in circulation, interstitial fluid, and skeletal muscle, at rest and in response to acute exercise. Seventeen college-aged subjects (11 women/6 men; 21.7 ± 3.7 yr) completed an acute ballistic exercise bout before and after the training program. Blood samples were collected pre-, mid-, and postexercise and analyzed for serum total IGF-I, free IGF-I, and IGF binding proteins (IGFBPs) 1–4. Dialysate and interstitial free IGF-I were analyzed in vastus lateralis (VL) interstitial fluid collected pre- and postexercise via microdialysis. Pre- and postexercise VL muscle biopsies were analyzed for IGF-I protein expression, IGF-I receptor phosphorylation (p-IGF-IR), and AKT phosphorylation (p-AKT). Following training, basal serum IGF-I, free IGF-I, IGFBP-2, and IGFBP-3 decreased whereas IGFBP-1 and IGFBP-4 increased. Training reduced basal dialysate and interstitial free IGF-I but had no effect on basal skeletal muscle IGF-I, p-IGF-IR, or p-AKT. Acute exercise elicited transient changes in IGF-I system concentrations and downstream anabolic signaling both pre- and posttraining; training did not affect this acute exercise response. Posttraining, acute exercise-induced changes in dialysate/interstitial free IGF-I were strongly correlated with the changes in intramuscular IGF-I expression, p-IGF-IR, and p-AKT. The divergent influence of resistance training on circulating/interstitial and skeletal muscle IGF-I demonstrates the importance of concurrent, multiple biocompartment analysis when examining the IGF-I system. As training elicited muscle hypertrophy, these findings indicate that IGF-I’s anabolic effects on skeletal muscle are mediated by local, rather than systemic mechanisms. NEW & NOTEWORTHY In the first investigation to assess resistance training’s effects on the IGF-I system in serum, interstitial fluid, and skeletal muscle, training decreased basal circulating and interstitial IGF-I but did not alter basal intramuscular IGF-I protein activity. Posttraining, acute exercise-induced interstitial IGF-I increases were strongly correlated with intramuscular IGF-I expression and signaling. These findings highlight the importance of multibiocompartment measurement when analyzing IGF-I and suggest that IGF-I’s role in hypertrophic adaptations is locally mediated.

Traumatic musculoskeletal injury (MSI) may involve changes in corticomotor structure and function, but direct evidence is needed. To determine the corticomotor basis of MSI, we examined interactions among skeletomotor function, corticospinal excitability, corticomotor structure (cortical thickness and white matter microstructure), and intermittent theta burst stimulation (iTBS)-induced plasticity. Nine women with unilateral anterior cruciate ligament rupture (ACL) 3.2 ± 1.1 yr prior to the study and 11 matched controls (CON) completed an MRI session followed by an offline plasticity-probing protocol using a randomized, sham-controlled, double-blind, cross-over study design. iTBS was applied to the injured (ACL) or nondominant (CON) motor cortex leg representation (M1

Kraemer, WJ, Caldwell, LK, Post, EM, DuPont, WH, Martini, ER, Ratamess, NA, Szivak, TK, Shurley, JP, Beeler, MK, Volek, JS, Maresh, CM, Todd, JS, Walrod, BJ, Hyde, PN, Fairman, C, and Best, TM. Body composition in elite strongman competitors. J Strength Cond Res 34(12): 3326-3330, 2020-The purpose of this descriptive investigation was to characterize a group of elite strongman competitors to document the body composition of this unique population of strength athletes. Data were collected from eligible competitors as part of a health screening program conducted over 5 consecutive years. Imaging was acquired using dual-energy x-ray absorptiometry (DXA), providing total body measures of fat mass, lean mass, and bone mineral content (BMC). Year to year, testing groups showed a homogenous grouping of anthropometric, body composition, and bone density metrics. Composite averages were calculated to provide an anthropometric profile of the elite strongman competitor (N = 18; mean ± SD): age, 33.0 ± 5.2 years; body height, 187.4 ± 7.1 cm; body mass, 152.9 ± 19.3 kg; body mass index, 43.5 ± 4.8 kg·m; fat mass, 30.9 ± 11.1 kg; lean mass, 118.0 ± 11.7 kg, body fat, 18.7 ± 6.2%, total BMC, 5.23 ± 0.41 kg, and bone mineral density, 1.78 ± 0.14 g·cm. These data demonstrate that elite strongman competitors are among the largest human male athletes, and in some cases, they are at the extreme limits reported for body size and structure. Elite strongman competitors undergo a high degree of mechanical stress, providing further insight into the potent role of physical training in mediating structural remodeling even into adulthood. Such data provide a glimpse into a unique group of competitive athletes pushing the limits not only of human performance but also of human physiology.

Animal data indicate that ketogenic diets are associated with improved mitochondrial function, but human data are lacking. We aimed to characterize skeletal muscle mitochondrial changes in response to a ketogenic diet combined with exercise training in healthy individuals. Twenty-nine physically active adults completed a 12-wk supervised exercise program after self-selection into a ketogenic diet (KD, n = 15) group or maintenance of their habitual mixed diet (MD, n = 14). Measures of metabolic health and muscle biopsies (vastus lateralis) were obtained before and after the intervention. Mitochondria were isolated from muscle and studied after exposure to carbohydrate (pyruvate), fat (palmitoyl-l-carnitine), and ketone (β-hydroxybutyrate+acetoacetate) substrates. Compared with MD, the KD resulted in increased whole body resting fat oxidation ( P < 0.001) and decreased fasting insulin ( P = 0.019), insulin resistance [homeostatic model assessment of insulin resistance (HOMA-IR), P = 0.022], and visceral fat ( P < 0.001). The KD altered mitochondrial function as evidenced by increases in mitochondrial respiratory control ratio (19%, P = 0.009), ATP production (36%, P = 0.028), and ATP/H2O2(36%, P = 0.033) with the fat-based substrate. ATP production with the ketone-based substrate was four to eight times lower than with other substrates, indicating minimal oxidation. The KD resulted in a small decrease in muscle glycogen (14%, P = 0.035) and an increase in muscle triglyceride (81%, P = 0.006). These results expand our understanding of human adaptation to a ketogenic diet combined with exercise. In conjunction with weight loss, we observed altered skeletal muscle mitochondrial function and efficiency, an effect that may contribute to the therapeutic use of ketogenic diets in various clinical conditions, especially those associated with insulin resistance.

Background: Increased soft-drink consumption has contributed to poor calcium intake with 90% of adolescent girls consuming less than the RDA for calcium.Purpose/objectives: The purpose of this inve...

Background Measures of handgrip strength have not only emerged as a clinically viable screening tool for determining risk for morbidity, functional disability, and early mortality, but also for helping to identify cognitive deficits. However, the phenomena that links low handgrip strength with cognitive decline remains unclear. The role of the muscular and neural systems, and their adaptations to muscle strengthening activities over the life course, may provide important information for how age-related changes to muscle mass, strength, and neural capacity influence cognition. Moreover, disentangling how handgrip strength and cognitive function are associated may help to inform healthcare providers working with aging adults and guide targeted interventions aiming to preserve muscle and cognitive functioning. Objective To 1) highlight and summarize evidence examining the associations of handgrip strength and cognitive functioning, and 2) provide directions for future research in this area. Methods Articles from the PubMed database were searched from November 2018-May 2019. The search term algorithm, inclusion and exclusion criteria were pre-specified by investigators. Results Several cross-sectional and longitudinal studies have revealed that measures of handgrip strength were associated with cognitive declines regardless of age demographics and the presence of comorbidities. Conclusion Handgrip strength can be used in clinical and epidemiological settings for helping to determine the onset and progression of cognitive impairment. Future research should continue to examine how handgrip strength and cognitive function are linked.

Kraemer, WJ, Caldwell, LK, Post, EM, Beeler, MK, Emerson, A, Volek, JS, Maresh, CM, Fogt, JS, Fogt, N, Häkkinen, K, Newton, RU, Lopez, P, Sanchez, BN, and Onate, JA. Arousal/stress effects of “Overwatch” eSports game competition in collegiate gamers. J Strength Cond Res XX(X): 000–000, 2022—To date, no physical response data are available for one of the most popular eSport games, Overwatch. The purpose of this investigation was to describe the stress signaling associated with competitive Overwatch play and to understand how acute hormonal responses may affect performance. Thirty-two male college-aged gamers (age: 21.3 ± 2.7 years; estimated time played per week: 18 ± 15 hours) completed the study. Subjects were randomly assigned to a 6-player team to compete in a tournament-style match. Salivary measures of cortisol and testosterone were collected immediately before (PRE) and after (POST) the first-round game, with the heart rate recorded continuously during the match. The mean characteristics were calculated for each variable and comparisons made by the skill level. Significance was defined as p ≤ 0.05. There were no differences in measures of salivary cortisol. A differential response pattern was observed by the skill level for testosterone. The low skill group displayed a significant increase in testosterone with game play (mean ± SD, testosterone PRE: 418.3 ± 89.5 pmol·L−1, POST: 527.6 ± 132.4 pmol·L−1, p < 0.001), whereas no change was observed in the high skill group. There were no differences in heart rate characteristics between skill groups. Overall, the average heart rate was 107.2 ± 17.8 bpm with an average max heart rate of 133.3 ± 19.1 bpm. This study provides unique physiological evidence that a sedentary Overwatch match modulates endocrine and cardiovascular responses, with the skill level emerging as a potential modulator. peerReviewed

Ultra-short-term (UST;5 min) heart rate variability (HRV) is increasingly used to indirectly assess autonomic nervous system modulation and physical health. However, UST HRV estimates may vary with measurement technique, physiological state, and data preprocessing. The purpose of this investigation was to assess the information content of UST HRV and its sensitivity to different physiological states and preprocessing techniques. 26 time, frequency, and non-linear HRV measures were determined in 80 healthy men (age: 22.1 ± 3.7 yr) and 25 women (age: 19.4 ± 2.8 yr) from 2-min ECG recordings during seated and standing rest, low-intensity exercise, and seated recovery after maximal exercise. For men, HRV measures obtained during each condition were further analyzed with principal component analysis, k-means clustering, and one-way ANCOVAs. Backward stepwise regression was used to determine the ability of UST HRV to predict aerobic fitness. The sensitivity of UST HRV estimates to different artifact correction procedures was determined with intraclass correlation coefficients. Compared with men, women displayed HRV characteristics suggestive of greater vagal modulation. Nearly 80% of HRV information content was distilled into three principal components comprised of similar measures across conditions. K-means clusters varied in composition and HRV characteristics but not aerobic fitness, which was best predicted by HRV during standing rest. HRV estimates differed depending on artifact correction procedures but were generally similar after individualized correction. Our results indicate that UST HRV measures display redundancy but convey state-specific information and do not strongly predict aerobic fitness in healthy men. Most UST HRV measures are robust to slight differences in artifact correction procedures.

Purpose Cancer-induced muscle wasting (i.e., cancer cachexia, CC) is a common and devastating syndrome that results in the death of more than 1 in 5 patients. Although primarily a result of elevated inflammation, there are multiple mechanisms that complement and amplify one another. Research on the use of exercise to manage CC is still limited, while exercise for CC management has been recently discouraged. Moreover, there is a lack of understanding that exercise is not a single medicine, but mode, type, dosage, and timing (exercise prescription) have distinct health outcomes. The purpose of this review was to examine the effects of these modes and subtypes to identify the most optimal form and dosage of exercise therapy specific to each underlying mechanism of CC. Methods The relevant literatures from MEDLINE and Scopus databases were examined. Results Exercise can counteract the most prominent mechanisms and signs of CC including muscle wasting, increased protein turnover, systemic inflammation, reduced appetite and anorexia, increased energy expenditure and fat wasting, insulin resistance, metabolic dysregulation, gut dysbiosis, hypogonadism, impaired oxidative capacity, mitochondrial dysfunction, and cancer treatments side-effects. There are different modes of exercise, and each mode has different sub-types that induce vastly diverse changes when performed over multiple sessions. Choosing suboptimal exercise modes, types, or dosages can be counterproductive and could further contribute to the mechanisms of CC without impacting muscle growth. Conclusion Available evidence shows that patients with CC can safely undertake higher-intensity resistance exercise programs, and benefit from increases in body mass and muscle mass.

Significance The popularity of competitive video game play is growing rapidly. Little is known about the ocular characteristics of esports participants. Refractive error and binocular measures in young adult gamers were similar to population norms. However, tear breakup time was lower, and accommodative lag was higher. Purpose In a recent report, very young video game players were found to have greater levels of refractive error and heterophoria and reduced stereopsis. The purpose of this study was to assess the visual and ocular characteristics of a group of recreational esports athletes to determine if the findings in young children were similar to findings in a group of young adult video game players. Methods Vision tests were performed on 36 college students during a video game combine event. Testing included high- and low-contrast visual acuity, autorefraction at distance and at 33 cm, stereoacuity, near heterophoria, and tear breakup time. Participants also indicated their level or rank in the game Overwatch. Results Fifteen participants were myopic, and 21 did not wear vision correction. The mean local stereopsis was 31.9 seconds. The mean of the esophoric value was 3.2 prism diopters, and the mean of the exophoric value was 5.7 prism diopters. The mean lag of accommodation was 0.81 D. The mean tear breakup time was 5.8 seconds. Average hours of play did not differ between those who wore vision correction and those who did not. There were no significant relationships between the hours of play and the ocular findings. Conclusions The prevalence of refractive error and the mean heterophoria were similar to population norms, and the mean stereoacuity was normal. However, accommodative lag was slightly higher, and the tear breakup time was lower than expected. Differences in these latter values were also noted between high- and low-level Overwatch players.

Background. Foods rich in saturated fatty acids (SFAs) have been discouraged by virtue of their cholesterol-raising potential, but this effect is modulated by the food source and background level of carbohydrate. Objective. We aimed to compare the consumption of palm stearin (PS) versus butter on circulating cholesterol responses in the setting of both a low-carbohydrate/high-fat (LC/HF) and high-carbohydrate/low-fat (HC/LF) diet in healthy subjects. We also explored effects on plasma lipoprotein particle distribution and fatty acid composition. Methods. We performed a randomized, controlled-feeding, cross-over study that compared a PS- versus a Butter-based diet in a group of normocholesterolemic, non-obese adults. A controlled canola oil-based ‘Run-In’ diet preceded the experimental PS and Butter diets. All diets were eucaloric, provided for 3-weeks, and had the same macronutrient distribution but varied in primary fat source (40% of the total fat). The same Run-In and cross-over experiments were done in two separate groups who self-selected to either a LC/HF (n = 12) or a HC/LF (n = 12) diet track. The primary outcomes were low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein (HDL)-C, triglycerides, and LDL particle distribution. Results. Compared to PS, Butter resulted in higher LDL-C in both the LC/HF (13.4%, p = 0.003) and HC/LF (10.8%, p = 0.002) groups, which was primarily attributed to large LDL I and LDL IIa particles. There were no differences between PS and Butter in HDL-C, triglycerides, or small LDL particles. Oxidized LDL was lower after PS than Butter in LC/HF (p = 0.011), but not the HC/LF group. Conclusions. These results demonstrate that Butter raises LDL-C relative to PS in healthy normocholesterolemic adults regardless of background variations in carbohydrate and fat, an effect primarily attributed to larger cholesterol-rich LDL particles.

Purpose: To evaluate the changes in the state of hydration in elite National Collegiate Athletic Association (NCAA) Division I college wrestlers during and after a season. Methods: Ohio State University wrestling team members (N = 6; mean [SD] age = 19.6 [1.1] y; height = 171.6 [2.9] cm; body mass = 69.5 [8.1] kg) gave informed consent to participate in the investigation with measurements (ie, body mass, urine-specific gravity [USG; 2 methods], Visual Analog Scale thirst scale, plasma osmolality) obtained during and after the season. Results: Measurements for USG, regardless of methods, were not significantly different between visits, but plasma osmolality was significantly (P = .001) higher at the beginning of the season—295.5 (4.9) mOsm·kg−1 compared with 279.6 (6.1) mOsm·kg−1 after the season. No changes in thirst ratings were observed, and the 2 measures of USG were highly correlated (r > .9, P = .000) at each time point, but USG and plasma osmolality were not related. Conclusions: A paradox in the clinical interpretation of euhydration in the beginning of the season was observed with the USG, indicating that the wrestlers were properly hydrated, while the plasma osmolality showed they were not. Thus, the tracking of hydration status during the season is a concern when using only NCAA policies and procedures. The wrestlers did return to normal euhydration levels after the season on both biomarkers, which is remarkable, as previous studies have indicated that this may not happen because of the reregulation of the osmol-regulatory center in the brain.

Handgrip strength is considered a biomarker of nutritional status and strength capacity, which are both linked to heart complications. However, it is not well understood how weakness, as measured by handgrip strength, factors into common heart conditions seen in aging adults such as chronic heart failure (CHF). The purpose of this study was to determine the association between weakness and incident CHF for aging Americans. Longitudinal-Panel. Physical measures were completed during enhanced face-to-face interviews. The core interview was typically conducted over the telephone. Data from 17,431 adults aged at least 50 years who identified as Black or White, completed interviews without a proxy, and participated in at least one wave of the 2006–2014 waves of the Health and Retirement Study were included. Handgrip strength was measured with a hand-held dynamometer. Healthcare provider diagnosed CHF was self-reported at each wave. Sex- and race-specific maximal handgrip strength cut-points were used for determining weakness (Black men

Fragala, MS, Cadore, EL, Dorgo, S, Izquierdo, M, Kraemer, WJ, Peterson, MD, and Ryan, ED. Resistance training for older adults: position statement from the national strength and conditioning association. J Strength Cond Res 33(8): 2019-2052, 2019-Aging, even in the absence of chronic disease, is associated with a variety of biological changes that can contribute to decreases in skeletal muscle mass, strength, and function. Such losses decrease physiologic resilience and increase vulnerability to catastrophic events. As such, strategies for both prevention and treatment are necessary for the health and well-being of older adults. The purpose of this Position Statement is to provide an overview of the current and relevant literature and provide evidence-based recommendations for resistance training for older adults. As presented in this Position Statement, current research has demonstrated that countering muscle disuse through resistance training is a powerful intervention to combat the loss of muscle strength and muscle mass, physiological vulnerability, and their debilitating consequences on physical functioning, mobility, independence, chronic disease management, psychological well-being, quality of life, and healthy life expectancy. This Position Statement provides evidence to support recommendations for successful resistance training in older adults related to 4 parts: (a) program design variables, (b) physiological adaptations, (c) functional benefits, and (d) considerations for frailty, sarcopenia, and other chronic conditions. The goal of this Position Statement is to a) help foster a more unified and holistic approach to resistance training for older adults, b) promote the health and functional benefits of resistance training for older adults, and c) prevent or minimize fears and other barriers to implementation of resistance training programs for older adults.

IntroductionKetogenic diets (KDs) that elevate ketones into a range referred to as nutritional ketosis represent a possible nutrition approach to address the emerging physical readiness and obesity challenge in the military. An emerging body of evidence demonstrates broad-spectrum health benefits attributed to being in nutritional ketosis, but no studies have specifically explored the use of a KD in a military population using daily ketone monitoring to personalize the diet prescription.Materials and MethodsTo evaluate the feasibility, metabolic, and performance responses of an extended duration KD, healthy adults (n = 29) from various military branches participated in a supervised 12-wk exercise training program. Fifteen participants self-selected to an ad libitum KD guided by daily measures of capillary blood ketones and 14 continued their normal mixed diet (MD). A battery of tests were performed before and after the intervention to assess changes in body mass, body composition, visceral fat, liver fat, insulin sensitivity, resting energy metabolism, and physical performance.ResultsAll KD subjects were in nutritional ketosis during the intervention as assessed by daily capillary beta-hydroxybutyrate (βHB) (mean βHB 1.2 mM reported 97% of all days) and showed higher rates of fat oxidation indicative of keto-adaptation. Despite no instruction regarding caloric intake, the KD group lost 7.7 kg body mass (range −3.5 to −13.6 kg), 5.1% whole-body percent fat (range −0.5 to −9.6%), 43.7% visceral fat (range 3.0 to −66.3%) (all p < 0.001), and had a 48% improvement in insulin sensitivity; there were no changes in the MD group. Adaptations in aerobic capacity, maximal strength, power, and military-specific obstacle course were similar between groups (p > 0.05).ConclusionsUS military personnel demonstrated high adherence to a KD and showed remarkable weight loss and improvements in body composition, including loss of visceral fat, without compromising physical performance adaptations to exercise training. Implementation of a KD represents a credible strategy to enhance overall health and readiness of military service members who could benefit from weight loss and improved body composition.

Prior research has illustrated that high volumes of aerobic exercise result in a reduction in basal concentrations of testosterone in men. Those studies were mostly conducted on recreational runners and identified reduced testosterone, but not concentrations low enough to be considered pathological. Therefore, the purpose of this study was to assess the basal concentrations of testosterone and cortisol in elite triathletes, as well as the impact of a World Championship race, on the acute responses of these hormones.A total of 22 men (age 40.6 [11.5] y, height 179 [6] cm, weight 77.0 [7.0] kg) who participated in the 2011 Ironman World Championships served as subjects. Resting blood samples were taken 2-4 d prior to provide a baseline (BL), as well as immediately, 1 d, and 2 d after the event and were later analyzed for total testosterone and cortisol concentrations.At BL, 9 men had a normal testosterone concentration, whereas 9 men fell within a "gray zone" and 4 other men demonstrated concentrations suggestive of deficiency. Testosterone was significantly lower than BL at 1 d (95% confidence interval [CI] 0.10-0.34, P .001, ES = 0.53) and 2 d (95% CI 0.01-0.21, P = .034, ES = 0.35) after the event. Cortisol was significantly different from BL at immediate post (95% CI 1.07-0.83, P .001, ES = 8.0). There were significant correlations between time and age (R = .68, P = .001), as well as BL testosterone and cortisol (R = .51, P = .015).Elite ultraendurance athletes may demonstrate not only reduced testosterone but also sometimes clinically low concentrations that could be indicative of androgen deficiency.

Within the parameters of the game, the various rugby codes popular around the world present a significant challenge to the athletes. Indeed, as a collision and contact sport, rugby requires a diverse physical make-up where the athlete must not only withstand the rigors of the game but also demonstrate the ability to express high levels of speed, strength, and power. Programs can achieve success provided that they consist of the three basic governing principles that control the prescription of each acute training program variable: specificity, progressive overload, and variation. There is a multitude of underlying biological foundations that will dictate the adaptive potential of an individual’s response to a workout. With the host of different periodized programs well established in both theory and practice, flexibility of workouts used became the basis of the approach. Flexible non-linear programs act as a “chameleon” programming model that can fade in and out of workout sequences as needed to achieve a mesocycle training goal.

This study aimed to analyze the effect of resistance training (RT) performed until volitional failure with low, moderate, and high loads on muscle hypertrophy and muscle strength in healthy adults and to assess the possible participant-, design-, and training-related covariates that may affect the adaptations.Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, MEDLINE, CINAHL, EMBASE, SPORTDiscus, and Web of Science databases were searched. Including only studies that performed sets to volitional failure, the effects of low- (15 repetitions maximum (RM)), moderate- (9-15 RM), and high-load (≤8 RM) RTs were examined in healthy adults. Network meta-analysis was undertaken to calculate the standardized mean difference (SMD) between RT loads in overall and subgroup analyses involving studies deemed of high quality. Associations between participant-, design-, and training-related covariates with SMD were assessed by univariate and multivariate network meta-regression analyses.Twenty-eight studies involving 747 healthy adults were included. Although no differences in muscle hypertrophy between RT loads were found in overall (P = 0.113-0.469) or subgroup analysis (P = 0.871-0.995), greater effects were observed in untrained participants (P = 0.033) and participants with some training background who undertook more RT sessions (P = 0.031-0.045). Muscle strength improvement was superior for both high-load and moderate-load compared with low-load RT in overall and subgroup analysis (SMD, 0.60-0.63 and 0.34-0.35, respectively; P0.001-0.003), with a nonsignificant but superior effect for high compared with moderate load (SMD, 0.26-0.28, P = 0.068).Although muscle hypertrophy improvements seem to be load independent, increases in muscle strength are superior in high-load RT programs. Untrained participants exhibit greater muscle hypertrophy, whereas undertaking more RT sessions provides superior gains in those with previous training experience.

PURPOSE This study aimed to analyze the effect of resistance training (RT) performed until volitional failure with low, moderate, and high loads on muscle hypertrophy and muscle strength in healthy adults and to assess the possible participant-, design-, and training-related covariates that may affect the adaptations. METHODS Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, MEDLINE, CINAHL, EMBASE, SPORTDiscus, and Web of Science databases were searched. Including only studies that performed sets to volitional failure, the effects of low- (>15 repetitions maximum (RM)), moderate- (9-15 RM), and high-load (≤8 RM) RTs were examined in healthy adults. Network meta-analysis was undertaken to calculate the standardized mean difference (SMD) between RT loads in overall and subgroup analyses involving studies deemed of high quality. Associations between participant-, design-, and training-related covariates with SMD were assessed by univariate and multivariate network meta-regression analyses. RESULTS Twenty-eight studies involving 747 healthy adults were included. Although no differences in muscle hypertrophy between RT loads were found in overall (P = 0.113-0.469) or subgroup analysis (P = 0.871-0.995), greater effects were observed in untrained participants (P = 0.033) and participants with some training background who undertook more RT sessions (P = 0.031-0.045). Muscle strength improvement was superior for both high-load and moderate-load compared with low-load RT in overall and subgroup analysis (SMD, 0.60-0.63 and 0.34-0.35, respectively; P < 0.001-0.003), with a nonsignificant but superior effect for high compared with moderate load (SMD, 0.26-0.28, P = 0.068). CONCLUSIONS Although muscle hypertrophy improvements seem to be load independent, increases in muscle strength are superior in high-load RT programs. Untrained participants exhibit greater muscle hypertrophy, whereas undertaking more RT sessions provides superior gains in those with previous training experience.