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Context Slips, trips, and falls are leading causes of musculoskeletal injuries in firefighters. Researchers have hypothesized that heat stress is the major contributing factor to these fireground injuries. Objective To examine the effect of environmental conditions, including hot and ambient temperatures, and exercise on functional and physiological outcome measures, including balance, rectal temperature, and perceived exertion. Design Randomized controlled clinical trial. Setting Laboratory environmental chamber. Patients or Other Participants A total of 13 healthy, active career firefighters (age = 26 ± 6 years [range = 19–35 years], height = 178.61 ± 4.93 cm, mass = 86.56 ± 16.13 kg). Intervention(s) Independent variables consisted of 3 conditions (exercise in heat [37.41°C], standing in heat [37.56°C], and exercise in ambient temperature [14.24°C]) and 3 data-collection times (preintervention, postintervention, and postrecovery). Each condition was separated from the others by at least 1 week and lasted a maximum of 40 minutes or until the participant reached volitional fatigue or a rectal temperature of 40.0°C. Main Outcome Measure(s) Firefighting-specific functional balance performance index, rectal temperature, and rating of perceived exertion. Results Exercise in the heat decreased functional balance, increased rectal temperature, and altered the perception of exertion compared with the other intervention conditions. Conclusions A bout of exercise in a hot, humid environment increased rectal temperature in a similar way to that reported in the physically active population and negatively affected measures of functional balance. Rather than independently affecting balance, the factors of exercise and heat stress appeared to combine, leading to an increased likelihood of slips, trips, and falls.

Osteoarthritis is the most common form of arthritis and is a substantial burden for patients with the disease. Currently, there is no cure for osteoarthritis, but many emerging therapies have been developed to aid in the mitigation of disease progression. When osteoarthritis reaches the end-stage of disease many patients undergo total joint arthroplasty to improve quality of life, yet some experience persistent pain and mobility limitations for extended periods following surgery. This review highlights recent therapeutic advancements in osteoarthritis treatment consisting of pharmacologics, nutraceuticals, biologics, and exercise while emphasizing the current state of post-arthroplasty rehabilitation.

The skeletal muscle hypertrophic response to resistance exercise training (RT) is highly variable across individuals. The molecular underpinnings of this heterogeneity are unclear. This study investigated transcriptional networks linked to RT-induced muscle hypertrophy, classified as 1) predictive of hypertrophy, 2) responsive to RT independent of muscle hypertrophy, or 3) plastic with hypertrophy. Older adults ( n = 31, 18 F/13 M, 70 ± 4 yr) underwent 14-wk RT (3 days/wk, alternating high-low-high intensity). Muscle hypertrophy was assessed by pre- to post-RT change in mid-thigh muscle cross-sectional area (CSA) [computed tomography (CT), primary outcome] and thigh lean mass [dual-energy X-ray absorptiometry (DXA), secondary outcome]. Transcriptome-wide poly-A RNA-seq was performed on vastus lateralis tissue collected pre- ( n = 31) and post-RT ( n = 22). Prediction networks (using only baseline RNA-seq) were identified by weighted gene correlation network analysis (WGCNA). To identify Plasticity networks, WGCNA change indices for paired samples were calculated and correlated to changes in muscle size outcomes. Pathway-level information extractor (PLIER) was applied to identify Response networks and link genes to biological annotation. Prediction networks ( n = 6) confirmed transcripts previously connected to resistance/aerobic training adaptations in the MetaMEx database while revealing novel member genes that should fuel future research to understand the influence of baseline muscle gene expression on hypertrophy. Response networks ( n = 6) indicated RT-induced increase in aerobic metabolism and reduced expression of genes associated with spliceosome biology and type-I myofibers. A single exploratory Plasticity network was identified. Findings support that interindividual differences in baseline gene expression may contribute more than RT-induced changes in gene networks to muscle hypertrophic response heterogeneity. Code/Data: https://github.com/kallavin/MASTERS_manuscript/tree/master .

Training civilians to be soldiers is a challenging task often resulting in musculoskeletal injuries, especially bone stress injuries. This study evaluated bone health biomarkers (P1NP/CTX) and whey protein or carbohydrate supplementations before and after Army initial entry training (IET). Ninety male IET soldiers participated in this placebo-controlled, double-blind study assessing carbohydrate and whey protein supplementations. Age and fat mass predicted bone formation when controlling for ethnicity, explaining 44% (p &lt, 0.01) of bone formation variations. Age was the only significant predictor of bone resorption (p = 0.02) when controlling for run, fat, and ethnicity, and these factors together explained 32% of the variance in bone resorption during week one (p &lt, 0.01). Vitamin D increased across training (p &lt, 0.01). There was no group by time interaction for supplementation and bone formation (p = 0.75), resorption (p = 0.73), Vitamin D (p = 0.36), or calcium (p = 0.64), indicating no influence of a supplementation on bone biomarkers across training. Age, fitness, fat mass, and ethnicity were important predictors of bone metabolism. The bone resorption/formation ratio suggests IET soldiers are at risk of stress injuries. Male IET soldiers are mildly to moderately deficient in vitamin D and slightly deficient in calcium throughout training. Whey protein or carbohydrate supplementations did not affect the markers of bone metabolism.

Context: Heat injury is a significant threat to military trainees. Different methods of heat mitigation are in use across military units. Mist fans are 1 of several methods used in the hot and humid climate of Fort Benning, Georgia. Objectives: To determine if (1) the mist fan or the cooling towel effectively lowered participant core temperature in the humid environment found at Fort Benning and (2) the mist fan or the cooling towel presented additional physiologic or safety benefits or detriments when used in this environment. Design: Randomized controlled clinical trial. Setting: Laboratory environmental chamber. Patients or Other Participants: Thirty-five physically active men aged 19 to 35 years. Intervention(s): (1) Mist fan, (2) commercial cooling towel, (3) passive-cooling (no intervention) control. All treatments lasted 20 minutes. Participants ran on a treadmill at 60% V̇o2max. Main Outcome Measure(s): Rectal core temperature, heart rate, thermal comfort, perceived temperature, perceived wetness, and blood pressure. Results: Average core temperature increased during 20 minutes of cooling (F1,28 = 64.76, P < .001, ηp2 = 0.70), regardless of group (F1,28 = 3.41, P = .08, ηp2 = 0.11) or condition (F1,28 < 1.0). Core temperature, heart rate, and blood pressure did not differ among the 3 conditions. Perceived temperature during 20 minutes of cooling decreased (F1,30 = 141.19, P < .001, ηp2 = 0.83) regardless of group or condition. Perceived temperature was lower with the mist-fan treatment than with the control treatment (F1,15 = 7.38, P = .02, ηp2 = 0.32). The mist-fan group perceived themselves to be cooler even at elevated core temperatures. Conclusions: The mist fan and cooling towel were both ineffective at lowering core temperature. Core temperature continued to increase after exercise in all groups. The mist fan produced feelings of coolness while the core temperature remained elevated, possibly increasing the risk of heat illness.

Context: Musculoskeletal injuries (MSIs) are among the most important challenges facing our military. They influence career success and directly affect military readiness. Several methods of screening initial entry training (IET) soldiers are being tested in an effort to predict which soldiers will sustain an MSI and to develop injury-prevention programs. The Army 1-1-1 Fitness Assessment was examined to determine if it could be used as a screening and MSI prediction mechanism in male IET soldiers.Objective: To determine if a relationship existed among the Army 1-1-1 Fitness Assessment results and MSI, MSI type, and program of instruction (POI) in male IET soldiers.Design: Retrospective cohort study.Setting: Fort Benning, Georgia.Patients or Other Participants: Male Army IET soldiers (N = 1788).Main Outcome Measure(s): The likelihood of sustaining acute and overuse MSI was modelled using separate logistic regression analyses. The POI, run time, push-ups and sit-ups (combined into a single score), and IET soldier age were tested as predictors in a series of linear models.Results: With POI controlled, slower run time, fewer push-ups and sit-ups, and older age were positively correlated with acute MSI; only slower run time was correlated with overuse MSI. For both MSI types, cavalry POIs had a higher risk of acute and overuse MSIs than did basic combat training, armor, or infantry POIs.Conclusions: The 1-1-1 Fitness Assessment predicted both the likelihood of MSI occurrence and type of MSI (acute or overuse). One-mile (1.6-km) run time predicted both overuse and acute MSIs, whereas the combined push-up and sit-up score predicted only acute MSIs. The MSIs varied by type of training (infantry, basic, armor, cavalry), which allowed the development of prediction equations by POI. We determined 1-1-1 Fitness Assessment cutoff scores for each event, thereby allowing the evaluation to be used as an MSI screening mechanism for IET soldiers.

This project investigated whey protein and/or carbohydrate supplementation effects on musculoskeletal injury (MSI) outcomes. Four groups of Initial Entry Training soldiers consumed either: (1) one protein (38.6 g, 293 kcal), (2) one carbohydrate (63.4 g, 291 kcal), (3) two protein (77.2 g, 586 kcal), or (4) two carbohydrate servings/day (126.8 g, 582 kcal) after physical training and before bed, or before bed only. Odds Ratio, Chi-square and Wilcoxon ranked-sum test compared supplementation/no supplementation, number of servings, and protein/carbohydrate for MSI and limited/missed duty rates and limited/missed training days. Non-matched pairs group averages were compared to 2015/2016 historical data. Non-supplemented soldiers were approximately 5&times, more likely to sustain a MSI (&chi, 2 = 58.48, p &lt, 0.001) and 4&times, more likely to miss training (&chi, 2 = 9.73, p = 0.003) compared to two servings. Non-supplemented soldiers missed five additional training days compared to two servings (W = 6059.5, p = 0.02). Soldiers consuming one serving were approximately 3&times, more likely to sustain a MSI than two servings (&chi, 2 = 9.55, p = 0.002). There was no difference in limited/missed duty rates or limited/missed training days between consuming one or two servings. There was no difference between consuming one serving versus no supplementation or protein versus carbohydrate supplementation for any outcome variable. Soldiers consuming 2 servings/day of protein or carbohydrate had lower MSI rates, limited/missed duty rates, and limited/ missed training days compared to non-supplemented soldiers.

We investigated the effects of whey protein (WP) supplementation on body composition and physical performance in soldiers participating in Army Initial Entry Training (IET). Sixty-nine, male United States Army soldiers volunteered for supplementation with either twice daily whey protein (WP, 77 g/day protein, ~580 kcal/day, n = 34, age = 19 &plusmn, 1 year, height = 173 &plusmn, 6 cm, weight = 73.4 &plusmn, 12.7 kg) or energy-matched carbohydrate (CHO) drinks (CHO, 127 g/day carbohydrate, ~580 kcal/day, n = 35, age = 19 &plusmn, 5 cm, weight = 72.3 &plusmn, 10.9 kg) for eight weeks during IET. Physical performance was evaluated using the Army Physical Fitness Test during weeks two and eight. Body composition was assessed using 7-site skinfold assessment during weeks one and nine. Post-testing push-up performance averaged 7 repetitions higher in the WP compared to the CHO group (F = 10.1, p &lt, 0.001) when controlling for baseline. There was a significant decrease in fat mass at post-training (F = 4.63, p = 0.04), but no significant change in run performance (F = 3.50, p = 0.065) or fat-free mass (F = 0.70, p = 0.41). Effect sizes for fat-free mass gains were large for both the WP (Cohen&rsquo, s d = 0.44) and CHO (Cohen&rsquo, s d = 0.42) groups. WP had a large effect on fat mass (FM) loss (Cohen&rsquo, s d = &minus, 0.67), while CHO had a medium effect (Cohen&rsquo, 0.40). Twice daily supplementation with WP improved push-up performance and potentiated reductions in fat mass during IET training in comparison to CHO supplementation.

Background Adequate dietary intake is important for promoting adaptation and prevention of musculoskeletal injury in response to large volumes of physical training such as Army Initial Entry Training (IET). The purpose of this study was to evaluate training volume and dietary intake and estimate energy balance in Army IET soldiers. Methods Dietary intake was assessed by collecting diet logs for three meals on each of three, non-consecutive days during the first week of IET. Training volume was measured across 13 weeks of training using Actigraph wGT3X accelerometers. Training intensity was classified using Sasaki vector magnitude three cut points. Energy expenditure estimates were calculated during weeks two and three of training using the modified Harris-Benedict equation and by estimation of active energy expenditure using metabolic equivalents for each classification of physical activity. All data is presented as mean ± standard deviation. Results A total of 111 male soldiers (ht. = ± 173 ± 5.8 cm, age = 19 ± 2 years, mass = 71.6. ± 12.4 kg) completed diet logs and were monitored with Actigraphs. IET soldiers performed on average 273 ± 62 min low, 107 ± 42 min moderate, 26 ± 22 min vigorous, and 10 ± 21 min of very vigorous intensity physical activity daily across 13 weeks. The estimated total daily energy expenditure was on average 3238 ± 457 kcals/d during weeks two and three of IET. Compared to week one caloric intake, there was a caloric deficit of 595 ± 896 kcals/d on average during weeks two and three of IET. Regression analysis showed that body weight was a significant predictor for negative energy balance (adj. R2 = 0.54, p

Background We examined the acute effects of different dietary protein sources (0.19 g, dissolved in 1 ml of water) on skeletal muscle, adipose tissue and hypothalamic satiety-related markers in fasted, male Wistar rats (~250 g). Methods Oral gavage treatments included: a) whey protein concentrate (WPC, n = 15); b) 70:30 hydrolyzed whey-to-hydrolyzed egg albumin (70 W/30E, n = 15); c) 50 W/50E (n = 15); d) 30 W/70E (n = 15); and e) 1 ml of water with no protein as a fasting control (CTL, n = 14). Results Skeletal muscle analyses revealed that compared to CTL: a) phosphorylated (p) markers of mTOR signaling [p-mTOR (Ser2481) and p-rps6 (Ser235/236)] were elevated 2–4-fold in all protein groups 90 min post-treatment (p