Search

Background: Athletes can face scenarios in which they are confined to bed rest (e.g., due to injury or illness). Existing research in otherwise healthy individuals indicates that those entering bed rest with the greatest physical performance level might experience the greatest performance decrements, which indirectly suggests that athletes might be more susceptible to the detrimental consequences of bed rest than general populations. Therefore, a comprehensive understanding of the effects of bed rest might help guide the medical care of athletes during and following bed rest. Objective: This systematic and narrative review aimed to (1) establish the evidence for the effects of bed rest on physical performance in athletes; (2) discuss potential countermeasures to offset these negative consequences; and (3) identify the time-course of recovery following bed rest to guide return-to-sport rehabilitation. Methods: This review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Four databases were searched (SPORTDiscus, Web of Science, Scopus, and MEDLINE/PubMed) in October of 2022, and studies were included if they were peer-reviewed investigations, written in English, and investigated the effects of horizontal bed rest on changes in physical capacities and qualities in athletes (defined as Tier 3–5 participants). The reporting quality of the research was assessed using a modified version of the Downs & Black checklist. Furthermore, findings from studies that involved participants in Tiers 1–2 were presented and synthesized using a narrative approach. Results: Our systematic review of the literature using a rigorous criterion of 'athletes' revealed zero scientific publications. Nevertheless, as a by-product of our search, seven studies were identified that involved apparently healthy individuals who performed specific exercise training prior to bed rest. Conclusions: Based on the limited evidence from studies involving non-athletes who were otherwise healthy prior to bed rest, we generally conclude that (1) bed rest rapidly (within 3 days) decreases upright endurance exercise performance, likely due to a rapid loss in plasma volume; whereas strength is reduced within 5 days, likely due to neural factors as well as muscle atrophy; (2) fluid/salt supplementation may be an effective countermeasure to protect against decrements in endurance performance during bed rest; while a broader array of potentially effective countermeasures exists, the efficacy of these countermeasures for previously exercise-trained individuals requires further study; and (3) athletes likely require at least 2–4 weeks of progressive rehabilitation following bed rest of ≤ 28 days, although the timeline of recovery might need to be extended depending on the underlying reason for bed rest (e.g., injury or illness). Despite these general conclusions from studies involving non-athletes, our primary conclusion is that substantial effort and research is still required to quantify the effects of bed rest on physical performance, identify effective countermeasures, and provide return-to-sport timelines in bona fide athletes. Trial Registration Number and Date of Registration: Registration ID: osf.io/d3aew; Date: October 24, 2022. [ABSTRACT FROM AUTHOR]

Spiering, BA, Clark, BC, Schoenfeld, BJ, Foulis, SA, and Pasiakos, SM. Maximizing strength: the stimuli and mediators of strength gains and their application to training and rehabilitation. J Strength Cond Res 37(4): 919–929, 2023—Traditional heavy resistance exercise (RE) training increases maximal strength, a valuable adaptation in many situations. That stated, some populations seek new opportunities for pushing the upper limits of strength gains (e.g., athletes and military personnel). Alternatively, other populations strive to increase or maintain strength but cannot perform heavy RE (e.g., during at-home exercise, during deployment, or after injury or illness). Therefore, the purpose of this narrative review is to (a) identify the known stimuli that trigger gains in strength; (b) identify the known factors that mediate the long-term effectiveness of these stimuli; (c) discuss (and in some cases, speculate on) potential opportunities for maximizing strength gains beyond current limits; and (d) discuss practical applications for increasing or maintaining strength when traditional heavy RE cannot be performed. First, by conceptually deconstructing traditional heavy RE, we identify that strength gains are stimulated through a sequence of events, namely: giving maximal mental effort, leading to maximal neural activation of muscle to produce forceful contractions, involving lifting and lowering movements, training through a full range of motion, and (potentially) inducing muscular metabolic stress. Second, we identify factors that mediate the long-term effectiveness of these RE stimuli, namely: optimizing the dose of RE within a session, beginning each set of RE in a minimally fatigued state, optimizing recovery between training sessions, and (potentially) periodizing the training stimulus over time. Equipped with these insights, we identify potential opportunities for further maximizing strength gains. Finally, we identify opportunities for increasing or maintaining strength when traditional heavy RE cannot be performed. [ABSTRACT FROM AUTHOR]

Introduction: This study characterized a sample of the first women to complete elite United States (US) military training. Methods: Twelve female graduates of the US Army Ranger Course and one of the first Marine Corps Infantry Officers Course graduates participated in 3 d of laboratory testing including serum endocrine profiles, aerobic capacity, standing broad jump, common soldiering tasks, Army Combat Fitness Test, and body composition (dual-energy x-ray absorptiometry, three-dimensional body surface scans, and anthropometry). Results: The women were 6 months to 4 yr postcourse graduation, 30 ± 6 yr (mean ± SD); height, 1.67 ± 0.07 m; body mass, 69.4 ± 8.2 kg; body mass index, 25.0 ± 2.3 kg·m−2. Dual-energy x-ray absorptiometry relative fat was 20.0% ± 2.0%; fat-free mass, 53.0 ± 5.9 kg; fat-free mass index, 20.0 ± 1.7 kg·m−2; bone mineral content, 2.75 ± 0.28 kg; bone mineral density, 1.24 ± 0.07 g·cm−2; aerobic capacity, 48.2 ± 4.8 mL·kg−1·min−1; total Army Combat Fitness Test score 505 ± 27; standing broad jump 2.0 ± 0.2 m; 123 kg casualty drag 0.70 ± 0.20 m·s−1, and 4 mile 47 kg ruck march 64 ± 6 min. All women were within normal healthy female range for circulating androgens. Physique from three-dimensional scan demonstrated greater circumferences at eight of the 11 sites compared with the standard military female. Conclusions: These pioneering women possessed high strength and aerobic capacity, low %BF; high fat-free mass, fat-free mass index, and bone mass and density; and they were not virilized based on endocrine measures as compared with other reference groups. This group is larger in body size and leaner than the average Army woman. These elite physical performers seem most comparable to female competitive strength athletes. [ABSTRACT FROM AUTHOR]

Introduction: The U.S. Army Occupational Physical Assessment Test (OPAT) is a pre-enlistment physical employment screening assessment developed to place recruits and soldiers into Military Occupational Specialties (MOSs) based on their physical capabilities in order to optimize performance and limit injury. The OPAT consists of the seated power throw (SPT), strength deadlift (SDL), standing long jump, and interval aerobic run. During the scientific validation of the OPAT, two variants of the SPT and two variants of the SDL were used. Although the OPAT was validated using both variants for each test, U.S. Army scientists and policymakers have received queries regarding how these variants compare to each other. Therefore, the purpose of this study was to compare different variants of the SPT and SDL.Materials and Methods: Thirty-two participants (14 male and 18 female) between the ages of 18 and 42 years visited the laboratory on one occasion and performed two variants of the SPT (seated on the ground [the current OPAT standard] versus seated in a chair with a 35 cm seat height) and two variants of the SDL (using a hex-bar [the current OPAT standard] versus using paired dumbbells). Testing order for the different variants was randomized. The protocol was approved by the U.S. Army Medical Research and Development Command Institutional Review Board.Results: Performing the SPT from a chair significantly (P < .05) increased performance when compared to performing the SPT from the ground (5.4 ± 1.3 m versus 5.0 ± 1.4 m, respectively). Values for the two SPT variants were correlated (tau = 0.90). Performing the SDL using the hex-bar significantly increased the maximal weight lifted when compared to performing the SDL using paired dumbbells (86.9 ± 18.4 kg versus 83.1 ± 18.0 kg, respectively). Values for the two SDL variants were correlated (tau = 0.83).Conclusions: Performing different variants of the SPT and SDL influenced the resulting score. Although these findings do not alter the administration or scoring of the OPAT, they do provide a valuable reference in the event of future inquiries regarding the development of the OPAT. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the reliability and construct validity of a battery of tests designed to assess soldier task performance. In the first part of the study (designed to assess test-retest reliability), 33 enlisted soldiers (31 men, 2 women; 23 ± 3 years; 1.75 ± 0.08 m; and 81.4 ± 12.8 kg) completed a 4-event “soldier task test battery” (STTB) on 4 occasions, each separated by at least 1 week. The STTB consisted of the following tests, in order: (a) 30-m grenade throw for accuracy; (b) running long jump while wearing a 20.5-kg load; (c) 1 repetition maximum box lift; and (d) 3.2-km load carriage time trial while wearing a 33-kg load. In the second part of the study (designed to assess construct validity), 41 male soldiers (22 ± 3 years; 1.75 ± 0.08 m; and 81.4 ± 12.9 kg) completed the STTB and a series of physical fitness tests. The physical fitness tests included measurements of body composition, muscular strength, muscular power, muscular endurance, and cardiovascular endurance. Overall performance on the STTB (reflected by the sum of z-scores across individual tests) demonstrated an intraclass correlation coefficient of 0.95 and was correlated to lean mass, Vo2 peak, and measures of muscular strength and power. Lean body mass and standing long jump predicted performance on the STTB (R2 = 0.41). In conclusion, this STTB can reliably assess performance of soldiering tasks. The relationships between the STTB and physical fitness tests can be used to develop training programs to prepare soldiers to perform physically demanding tasks. [ABSTRACT FROM AUTHOR]

Nearly every physically active person encounters periods in which the time available for exercise is limited (e.g., personal, family, or business conflicts). During such periods, the goal of physical training may be to simply maintain (rather than improve) physical performance. Similarly, certain special populations may desire to maintain performance for prolonged periods, namely athletes (during the competitive season and offseason) and military personnel (during deployment). The primary purpose of this brief, narrative review is to identify the minimal dose of exercise (i.e., frequency, volume, and intensity) needed to maintain physical performance over time. In general populations, endurance performance can be maintained for up to 15 weeks when training frequency is reduced to as little as 2 sessions per week or when exercise volume is reduced by 33-66% (as low as 13-26 minutes per session), as long as exercise intensity (exercising heart rate) is maintained. Strength and muscle size (at least in younger populations) can be maintained for up to 32 weeks with as little as 1 session of strength training per week and 1 set per exercise, as long as exercise intensity (relative load) is maintained; whereas, in older populations, maintaining muscle size may require up to 2 sessions per week and 2-3 sets per exercise, while maintaining exercise intensity. Insufficient data exists to make specific recommendations for athletes or military personnel. Our primary conclusion is that exercise intensity seems to be the key variable for maintaining physical performance over time, despite relatively large reductions in exercise frequency and volume. [ABSTRACT FROM AUTHOR]

The article discusses research which was conducted to investigate the effects of short-term physical training on the acute hormonal response (i.e., growth hormone, total and free insulin-like growth factor I [lGF-I], and IGF binding proteins [IGFBP]-1, IGFBP-2, and lGFBP-3) to resistance exercise (RE) in women. Researchers evaluated 46 women who either performed endurance training, resistance training, combined training or no training. They found that participation in resistance training increased total IGF-I and reduced IGFBP-1 concentrations during acute RE, indicating exercise mode-specific adaptations in the circulating IGF-I system.

The purpose of this study was to determine the reliability of military-relevant tests designed to assess soldier readiness. Forty-seven soldiers (46 men, 1 woman; 22 ± 3 years; 80.4 ± 11.7 kg) performed each of seven soldier readiness tests on four different occasions over the course of 8 weeks. The soldier readiness tests were: (1) 3.2-kin load carriage (LC) time-trial, (2) running long jump (RLJ), (3) one-repetition maximum box lift (1RMBL), (4) 10-minute repetitive box lift and carry (RBLC), (5) simulated victim rescue (VR), (6) mock grenade throw (GT) for accuracy, and (7) simulated combat rushes (CR). Repeated measures analysis of variance revealed significant learning effects for 1RMBL, RBLC, and GT; these tests required two (1RMBL and RBLC) or three (GT) trials to obtain statistically stable values. The intraclass correlation coefficient was 0.78 to 0.89 for all tests. LC, 1RMBL, RBLC, CR, and RLJ all demonstrated standard error of measurement values that were 3% to 5%, whereas VR and GT were 9% and 36%, respectively. In conclusion, the IRMBL, RBLC, and GT tests required familiarization before a stable value was obtained. The LC, 1RMBL, RBLC, CR, and RLJ tests (and, to a lesser degree, the VR test) demonstrated reasonably acceptable levels of reliability and measurement error, whereas the GT test did not. [ABSTRACT FROM AUTHOR]

The article presents a set of exercise tests designed to provide a means of assessing neuromuscular function in subjects who have been unweighted for some time, due to spaceflight, bed rest, or immobilization. An overview of related previous research is provided, along with details of the tests, which include the use of leg exercise machines and bench pressing.

Abstract: The purpose of this study was to determine the influence of endogenous circulating testosterone (T) on muscle androgen receptor (AR) responses to acute resistance exercise (RE). Six healthy men (26±4 years; 176±5cm; 75.8±11.4kg) performed a knee extension exercise protocol on two occasions separated by 1–3 weeks. Rest preceded one trial (i.e., control [CON] trial) and a high-volume upper-body RE protocol designed to increase circulating T preceded the other trial (i.e., high T [HT] trial). Serial blood samples were obtained throughout each trial to determine circulating T concentrations. Biopsies of the vastus lateralis were obtained pre-RE (REST), 10-min post-RE (+10), and 180-min post-RE (+180) to determine muscle AR content. Circulating T concentrations remained stable during CON. Alternately, HT significantly (p ≤0.05) increased T concentrations above resting values (+16%). Testosterone area-under-the-time curve during HT exceeded CON by 14%. AR content remained stable from REST to +10 in both trials. Compared to the corresponding +10 value, muscle AR content at +180 tended to decrease during CON (−33%; p =0.10) but remained stable during HT (+40%; p =0.17). Muscle AR content at +180 during the HT trial exceeded the corresponding CON value. In conclusion, acute elevations in circulating T potentiated muscle AR content following RE. [Copyright &y& Elsevier]

The article reports about the condition of muscle damage and hormonal status of athletes in a national collegiate athletic division I football game. This study examined the recovery markers of the skeletal muscle tissue damage in anabolic and catabolic hormones to discover the process of tissue and muscle recovery.

Recent advances in molecular biology have elucidated some of the mechanisms that regulate skeletal muscle growth. Logically, muscle physiologists have applied these innovations to the study of resistance exercise (RE), as RE represents the most potent natural stimulus for growth in adult skeletal muscle. However, as this molecular-based line of research progresses to investigations in humans, scientists must appreciate the fundamental principles of RE to effectively design such experiments. Therefore, we present herein an updated paradigm of RE biology that integrates fundamental RE principles with the current knowledge of muscle cellular and molecular signalling. RE invokes a sequential cascade consisting of: (i) muscle activation; (ii) signalling events arising from mechanical deformation of muscle fibres, hormones, and immune/inflammatory responses; (iii) protein synthesis due to increased transcription and translation; and (iv) muscle fibre hypertrophy. In this paradigm. RE is considered an 'upstream' signal that determines specific downstream events. Therefore, manipulation of the acute RE programme variables (i.e. exercise choice, load, volume, rest period lengths, and exercise order) alters the unique 'fingerprint" of the RE stimulus and subsequently modifies the downstream cellular and molecular responses. [ABSTRACT FROM AUTHOR]

The article presents a study which examined the impact of L-carnitine L-tartrate (LCLT) supplementation on muscle tissue oxygenation during and after resistance exercise. Subjects of the study include nine resistance-trained men, who have ingested placebo for 23 days. Results have shown that enhanced oxygen consumption could reduce muscle oxygenation during the LCLT trial.

The article reports on the study of elevated circulating hormones and their effects on resistance exercise (RE) caused by alter protein kinase B (Akt). The study aims to find out if elevated circulating hormones regulate the signaling response of RE due to Akt. It is participated by seven healthy men who executed lower-body RE protocols particularly knee extensions for three weeks. It includes RE protocols which contain low-circulating hormonal concentration (LHC) trial, high-volume upper-body, and high-circulating hormonal concentration (HHC) trial. The study finds out that HHC trial has greater growth hormone (GH), ribosomal protein kinase, phosphorylation, glycogen synthase kinase-3², and cortisol concentrations than LHC trial.

L-carnitine L-tartrate (LCLT) supplementation beneficially affects markers of postexercise metabolic stress and muscle damage. However, to date, no study has determined the dose response of LCLT to elicit such responses. Therefore, the purpose of this study was to determine the effects of different doses of LCLT on criterion variables previously shown to be responsive to LCLT supplementation. Eight healthy men (22 ± 3y,174 ± 5 cm, 83.0 ± 15.3 kg) were supplemented with 0 g, 1 g, and 2 g of LCLT for 3 weeks and then performed a bout of resistance exercise (5 sets of 15-20 repetition maximum with a 2-min rest between sets) with associated blood draws. This procedure was performed in a balanced, randomized, repeated measures design. Serum carnitine concentrations increased (p ≤ 0.05) following the 1 g and 2 g doses, with the 2-g dose providing the highest carnitine concentrations. The 1- and 2-g doses reduced postexercise serum hypoxanthine, serum xanthine oxidase, serum myoglobin, and perceived muscle soreness. In conclusion, both the 1- and 2-g doses were effective in mediating various markers of metabolic stress and of muscle soreness. Use of LCLT appears to attenuate metabolic stress and the hypoxic chain of events leading to muscle damage after exercise. [ABSTRACT FROM AUTHOR]

Skeletal muscle displays an impressive capability to adapt to various stimuli. Exercise and physical activity, in their many forms, present specific stresses to muscle. Depending on the exact nature of the stress, muscle may adapt by increasing size, improving neuromuscular performance, or enhancing endurance capabilities. In this article, we provide an overview of the basics of neuromuscular physiology, principles of exercise training, adaptations to exercise, and the role of the endocrine system and intramuscular signalling pathways for mediating these responses and adaptations. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Airborne ultrafine and fine particulate matter (PM 1 from fossil-fueled internal combustion engines may cause abnormal airway narrowing. Because of high PM 1 exposure from ice resurfacing machines, the ice-rink athlete is especially vulnerable to PM 1 toxicity. The purpose of this study was to evaluate protection by a single dose of montelukast in college ice hockey players following PM 1 exposure exercise. Nine male ice hockey players (age 19.3 &PlusMinus; 1.22 yr) performed 4 randomized, double-blinded, high-intensity, 6-min cycle ergometer trials in low [PM 1 ] (2260 &PlusMinus; 500 particles/cm 3 ) and high [PM 1 ] (348,600 &PlusMinus; 121,600 particles/cm 3 ) after placebo or montelukast. Pre- and postspirometry showed similar peak FEV 1 (forced expiratory volume in 1 s) falls between placebo and montelukast after low [PM 1 ] trials (14.5 &PlusMinus; 18.06 vs. 9.5 &PlusMinus; 11.75% of baseline, respectively). Peak FEV 1 falls after high [PM 1 ] trials were greater for placebo than for montelukast (17.3 &PlusMinus; 9.79% vs. 1.7 &PlusMinus; 5.77% of baseline; p < .0001). High [PM 1 ] FEV 1 fall after exercise following montelukast ingestion was less than after exercise following placebo ingestion under high and low [PM 1 ] conditions and after exercise following montelukast ingestion under low [PM 1 ] conditions at 5, 10, and 15 min postchallenge (p < .004, .0006, .009, respectively). Montelukast provided greater protection against bronchoconstriction after exercise during high [PM 1 ] than low [PM 1 ] exposure (&nvsim;90% vs. &nvsim;35%), suggesting that bronchoconstriction from PM 1 exposure is predominately leukotriene mediated. The precise mechanism of airborne PM 1 -induced leukotriene-mediated airway narrowing remains unclear. [ABSTRACT FROM AUTHOR]

Athletes are required to provide objective documentation of exercise-induced bronchoconstriction(EIB) to useβ2-agonists during Olympic competition. A positive response to bronchial provocation by eucapnic voluntary hyperventilation(EVH) is considered acceptable confirmation of EIB. Thirty times forced expiratory volume in the first second(FEV1) is recommended as EVH target ventilation(TV), an intensity intended to estimate 85% of maximal voluntary ventilation(MVV). There is a paucity of data examining the accuracy of predicting MVV from FEV1 in elite athletes. The purpose of this study was to evaluate the efficacy of 30 × FEV1 as standardized EVH TV. Maximal minute ventilation during exercise(VEmax) and pulmonary function of 78 elite winter athletes(25 males, 53 females; 25 EIB positive, 53 normal) were analyzed retrospectively. Adequacy and variability of the equation was ascertained by examining the ratio of EVH TV(30 × FEV1) to VEmax. VEmax was 99 ± 11% of predicted MVV(35 × FEV1) and was positively related(r = 0.85, p ≤ 0.05). TV was 88 ± 9% of VEmax(range: 64–109). For elite athletes, the high variability in 30 × FEV1 to standardize TV for EVH may result in under-diagnosis for low-end outliers. Since VEmax of elite endurance athletes is typically known(via maximal aerobic testing) we recommend 85% VEmax as a more accurate and reliable method to establish EVH TV for this group; if VEmax is not available, then 85% of measured MVV may be used. [ABSTRACT FROM AUTHOR]

Study objectives: Diagnosis and medical intervention for exercise-induced bronchospasm (EIB) are often based on self-reported symptoms, without spirometric confirmation. Inspiratory stridor (IS), a symptom of vocal cord dysfunction (VCD), is frequently mistaken for EIB wheeze. Athletes with exercise IS that spontaneously resolves on activity cessation are suspect for VCD and may not have EIB. This study estimated IS prevalence in elite athletes and determined its relationship to EIB. Subjects/methods: Three hundred seventy athletes (174 female and 196 male subjects) provided a medical history, and underwent spirometry before and after exercise challenge. Exercise challenges were conducted in cold, dry ambient conditions. EIB positive (EIB +) was defined as a ≥ 10% postexercise fall in FEV[sub 1]. Athletes were monitored for IS during exercise; 78.4% of the athletes in this study (n = 290) were tested on multiple occasions. Results: EIB was identified in 30% of 370 athletes tested (58 female and 53 male subjects). IS was observed in 5.1% (18 female and 1 male subjects) during exercise and spontaneously resolved in these subjects within 5 min after exercise cessation. Ten IS-positive (IS +) athletes (52.6%) were EIB +, and 8 of these athletes had a previous EIB diagnosis; however, β[sub 2]-agonist treatment resolved IS in only 2 subjects. Eight of nine IS +/EIB-negative (EIB -) athletes had a previous EIB diagnosis; seven subjects received β[sub 2]-agonist treatment with no IS resolution. Resting spirometric measurements did not distinguish IS, but postexercise mid-flow (FEF[sub 50]/FIF[sub 50]) ratio > 1.5 was more frequent (33%, p < 0.05) among IS + athletes. The FEF[sub 50]/EIF[sub 50] ratio was higher for IS +/EIB + athletes than for IS -/EIB + athletes (1.97 ± 1.69 vs 0.81 ± 0.39, p < 0.05). The postexercise fall in FVC was greater (p < 0.05) for IS +/EIB - athletes (9.2 ± 5.0%) than for IS-negative (IS -)/EIB - athletes (5... [ABSTRACT FROM AUTHOR]

Purpose: Our goal was to quantify if small (1%-3%) changes in running economy quantitatively affect distance-running performance. Based on the linear relationship between metabolic rate and running velocity and on earlier observations that added shoe mass increases metabolic rate by ~1% per 100 g per shoe, we hypothesized that adding 100 and 300 g per shoe would slow 3000-m time-trial performance by 1% and 3%, respectively. Methods: Eighteen male sub-20-min 5-km runners completed treadmill testing, and three 3000-m time trials wearing control shoes and identical shoes with 100 and 300 g of discreetly added mass. We measured rates of oxygen consumption and carbon dioxide production and calculated metabolic rates for the treadmill tests, and we recorded overall running time for the time trials. Results: Adding mass to the shoes significantly increased metabolic rate at 3.5 m⋅s-1 by 1.11% per 100 g per shoe (95% confidence interval = 0.88%-1.35%). While wearing the control shoes, participants ran the 3000-m time trial in 626.1 ± 55.6 s. Times averaged 0.65% ± 1.36% and 2.37% ± 2.09% slower for the +100-g and +300-g shoes, respectively (P < 0.001). On the basis of a linear fit of all the data, 3000-m time increased 0.78% per added 100 g per shoe (95% confidence interval = 0.52%-1.04%). Conclusion: Adding shoe mass predictably degrades running economy and slows 3000-m time-trial performance proportionally. Our data demonstrate that laboratory-based running economy measurements can accurately predict changes in distance-running race performance due to shoe modifications. [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted to investigate the influence training frequency had on the perceived health status and fitness levels of deployed National Guard soldiers. Researchers evaluated 88 soldiers. They found that soldiers who trained three or more times per week experienced better fitness levels and perceived health during deployments.

The purpose of this study was to determine the influence of a comprehensive multi-component nutritional supplement on performance, hormonal, and metabolic responses to an acute bout of resistance exercise. Nine healthy subjects ingested either Muscle Fuel™ (MF) or a matched placebo (PL) for 7 days. Subjects then reported to the laboratory, ingested the corresponding supplement, and performed two consecutive days of heavy resistance exercise testing with associated blood draws. MF supplementation improved vertical jump (VJ) power output and the number of repetitions performed at 80% of one repetition maximum (1RM). Additionally, MF supplementation potentiated growth hormone (GH), testosterone, and insulin-like growth factor-1 responses to exercise. Concentrations of circulating myoglobin and creatine kinase (CK) were attenuated immediately following resistance exercise during the MF trial, indicating that MF partially mediated some form of exercise-induced muscle tissue damage. In summary MF enhanced performance and hormonal responses associated with an acute bout of resistance exercise. These responses indicate that MF supplementation augments the quality of an acute bout of resistance exercise thereby increasing the endocrine signaling and recovery following heavy resistance exercise. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the influence of a comprehensive multi-component nutritional supplement on performance, hormonal, and metabolic responses to an acute bout of resistance exercise. Nine healthy subjects ingested either Muscle Fuel (MF) or a matched placebo (PL) for 7 days. Subjects then reported to the laboratory, ingested the corresponding supplement, and performed two consecutive days of heavy resistance exercise testing with associated blood draws. MF supplementation improved vertical jump (VJ) power output and the number of repetitions performed at 80% of one repetition maximum (1RM). Additionally, MF supplementation potentiated growth hormone (GH), testosterone, and insulin-like growth factor-1 responses to exercise. Concentrations of circulating myoglobin and creatine kinase (CK) were attenuated immediately following resistance exercise during the MF trial, indicating that MF partially mediated some form of exercise-induced muscle tissue damage. In summary MF enhanced performance and hormonal responses associated with an acute bout of resistance exercise. These responses indicate that MF supplementation augments the quality of an acute bout of resistance exercise thereby increasing the endocrine signaling and recovery following heavy resistance exercise. [ABSTRACT FROM AUTHOR]

National Collegiate Athletic Association Division I athletes were tested to determine the load at which maximal mechanical output is achieved. Athletes performed power testing at 30, 40, 50, 60, and 70% of individual 1 repetition maximum (1RM) in the squat jump, bench press, and hang pull exercises. Additionally, hang pull power testing was performed using free-form (i.e., barbell) and fixed-form (i.e., Smith machine) techniques. There were differences between genders in optimal power output during the squat jump (30-40% of 1RM for men; 30-50% of 1RM for women) and bench throw (30% of 1RM for men; 30-50% of 1RM for women) exercises. There were no gender or form interactions during the hang pull exercise; maximal power output during the hang pull occurred at 30-60% of 1RM. In conclusion, these results indicate that (a) gender differences exist in the load at which maximal power output occurs during the squat jump and bench throw; and (b) although no gender or form interactions occurred during the hang pull exercise, greater power could be generated during fixed-form exercise. In general, 30% of 1RM will elicit peak power outputs for both genders and all exercises used in this study, allowing this standard percentage to be used as a starting point in order to train maximal mechanical power output capabilities in these lifts in strength trained athletes. [ABSTRACT FROM AUTHOR]

Resistance exercise intensity is commonly prescribed as a percent of 1 repetition maximum (1RM). However, the relationship between percent 1RM and the number of repetitions allowed remains poorly studied, especially using free weight exercises. The purpose of this study was to determine the maximal number of repetitions that trained (T) and untrained (UT) men can perform during free weight exercises at various percentages of 1RM. Eight T and 8 UT men were tested for 1RM strength. Then, subjects performed 1 set to failure at 60, 80, and 90% of 1RM in the back squat, bench press, and arm curl in a randomized, balanced design. There was a significant (p < 0.05) intensity × exercise interaction. More repetitions were performed during the back squat than the bench press or arm curl at 60% 1RM for T and UT. At 80 and 90% 1RM, there were significant differences between the back squat and other exercises; however, differences were much less pronounced. No differences in number of repetitions performed at a given exercise intensity were noted between T and UT (except during bench press at 90% 1RM). In conclusion, the number of repetitions performed at a given percent of 1RM is influenced by the amount of muscle mass used during the exercise, as more repetitions can be performed during the back squat than either the bench press or arm curl. Training status of the individual has a minimal impact on the number of repetitions performed at relative exercise intensity. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the impact of a very slow (VS) velocity and a self-selected volitional (VOL) velocity at varying intensities on repetition number, peak force, peak power, and total volume in the squat and shoulder press exercises. On separate testing days, 9 resistance trained men (age: 23.9 ± 2.5 years; height: 174.8 ± 6.5 cm; body mass: 80.1 ± 12.4 kg) performed a squat (SQ) and shoulder press (SP) exercise at 60 or 80% of 1 repetition maximum (1RM) at either VOL or VS (10-second eccentric and 10-second concentric actions) velocity for as many repetitions as possible. Force, power, and volume (repetitions × kg) were also determined. Subjects performed significantly fewer repetitions (p ≤ 0.05) in the VS exercises (60% VS SQ 5 ± 1 vs. VOL SQ 24 ± 2; 80% VS SQ 2 ± 0 vs. VOL SQ 12 ± 1; 60% VS SP 4 ± 1 vs. VOL SP 14 ± 2; 80% VS SP 1 ± 0 vs. VOL SP 6 ± 1). Peak force and power were significantly higher at the VOL speed (peak force [in newtons]: 60% VS SQ 564.4 ± 77.3 vs. VOL SQ 1229.0 ± 134.9 N; 80% VS SQ 457.3 ± 27.9 vs. VOL SQ 1059.3 ± 104.7 N; 60% VS SP 321.6 ± 37.8 vs. VOL SP 940.7 ± 144.8 N; 80% VS SP 296.5 ± 24.7 vs. VOL SP 702.5 ± 57.7 N; and peak power [in watts]: 60% VS SQ 271.2 ± 40.1 vs. VOL SQ 783.2 ± 129.1 W; 80% VS SQ 229.3 ± 49.5 vs. VOL SQ 520.2 ± 85.8 W; 60% VS SP 91.3 ± 21.9 vs. VOL SP 706.6 ± 151.4 W; 80% VS SP 78.1 ± 19.8 vs. VOL SP 277.6 ± 46.4 W). VOL speed elicited higher total volume than the VS velocity. The results of this study indicate that a VS velocity may not elicit appropriate levels of force, power, or volume to optimize strength and athletic performance. [ABSTRACT FROM AUTHOR]

The order of resistance exercises within a training session may have a vital impact on the quality of the constituent exercises performed. However, very few studies have documented the specific influence of exercise order. Therefore, the purpose of this study was to examine the effect of exercise order on back squat performance in the context of a whole-body workout. Nine resistance-trained male subjects (age: 24 ± 4 years, body mass: 81.5 ± 15.3 kg, resistance-training experience: 7 ± 4 years) performed the back squat exercise (4 sets at 85% of 1 repetition maximum) on 2 separate occasions in a balanced, crossover design. During one protocol, the squat exercise was performed first (protocol A); during the other protocol, it was performed after a whole-body resistance-exercise session (protocol B). Number of repetitions, average power, and rating of perceived exertion (RPE) were collected during each set of the squat exercise. All subjects performed significantly (p < 0.01) more repetitions during set 1 when they performed protocol A (8.0 ± 1.9 repetitions) compared with protocol B (5.4 ± 2.7 repetitions). The average power for each set was higher during protocol B compared with protocol A. There were no significant differences in RPE values between the 2 protocols. In conclusion, performing the barbell back squat first in an exercise session allowed the completion of more total repetitions. However, this study showed that performing the squat exercise after a whole-body workout session may result in greater power output if the squat is preceded by a power exercise (i.e., hang pull). This phenomenon may have been due to postactivation potentiation. [ABSTRACT FROM AUTHOR]

Strenuous physical exercise can induce damage and injury to muscle tissue that is manifested as soreness, a decreased range of motion, swelling, pain, and impaired functional capacity. Compression is a therapeutic technique widely used in the treatment of muscle and other soft tissue injuries, though evidence in support of this remedial therapy has until recently being largely anecdotal. Recent scientific research has indicated that external compression can be an effective treatment that minimises swelling, improves the alignment and mobility of scar tissue, and improves proprioception in an injured joint consequent to eccentric damage models and DOMS. The principles behind compressive treatment methods are based on known principles affecting the lymphatic system, reducing oedema, skeletal muscle contractions, local pressure gradients, and the influence of gravity. The rationale for applying compression to injured tissue are, (i) its theoretical ability to reduce oedema via the creation of an external pressure gradient, (ii) by reducing the space available for swelling to accumulate, haemorrhage and haematoma formation can be decreased, and (iii) providing mechanical support that can facilitate the capacity to produce force which is critical for rehabilitation. Compression involves a "dynamic immobilisation" strategy that allows for greater neural input and the capacity for limited movement during the recovery process. This treatment protocol represents an easily administered therapy that can be used effectively without great financial cost. [ABSTRACT FROM AUTHOR]

Study objective: For the 2002 Winter Olympic Games, athletes were required to submit objective evidence of asthma or exercise-induced bronchoconstriction (EIB) for approval to inhale a β2-agonist. Eucapnic voluntary hyperventilation (EVH) was recommended as a laboratory challenge that would identify airway hyperresponsiveness (AHR) consistent with EIB. The objective was to compare the change in FEV1 provoked by EVH with that provoked by exercise in cold weather athletes. Design: Spirometry was measured before and for 15 min after challenges. The two challenges were performed in random order at least 24 h apart. Setting: EVH was performed in the laboratory at 19°C, and exercise took place in the field in the cold (2°C, 45% relative humidity). Participants: Thirty-eight athletes (25 female subjects; median age, 16 years). Interventions: For the EVH, athletes inhaled dry air containing 5% carbon dioxide for 6 min at a target ventilation equivalent to 30 times baseline FEV1. Exercise was performed by cross-country skiing, ice skating, or running for 6 to 8 min. Measurements and results: AHR consistent with EIB was defined as ≥10% fall in FEV1 from baseline after challenge. Eleven athletes were exercise positive (EX+) [FEV1 fall, 20.5 ± 7.3%], and 17 athletes were EVH positive (FEV1 fall, 14.5 ± 4.5%) [mean ± SD]. Of 19 subjects with AHR, 58% were identified by exercise and 89% were identified by EVH. EVH identified 9 of 11 subjects who were EX+ and a further 8 subjects with potential for EIB. The average ventilation during EVH was 28 times FEV1. Conclusion: Performing EVH for 6 min in the laboratory had a greater chance of identifying AHR in these athletes compared with 6 to 8 min of field exercise in the cold. The EVH test will be useful to evaluate elite summer sports athletes whose widely different forms of exercise provide an "equipment" challenge to any laboratory. [ABSTRACT FROM AUTHOR]

Purpose: To determine the effects of US Army Ranger Training, an 8-week, physically demanding program (energy expenditure of 2,500-4,500 kcal/day) with energy restriction (deficit of 1,000-4,000 kcal/day) and sleep deprivation (<4 h sleep/night) on bone metabolism. Methods: Blood was collected from 22 men (age 24 ± 4 years) before and after training. Follow-up measurements were made in a subset of 8 subjects between 2 and 6 weeks after training. Serum was analyzed for bone formation biomarkers [bone alkaline phosphatase (BAP) and osteocalcin (OCN)], bone resorption biomarkers [C-telopeptide cross-links of type I collagen (CTX) and tartrate-resistant acid phosphatase (TRAP5b)], calcium, parathyroid hormone (PTH), and vitamin D (25(OH)D). Data were analyzed using a paired t test to compare baseline to immediate post-training measures. A repeated-measures ANOVA with time as the only factor was used to analyze data on the subset of 8 subjects who completed follow-up data collection. Results: BAP and OCN significantly decreased by 22.8 ± 15.5 % (pre 41.9 ± 10.1; post 31.7 ± 7.8 ng/ml) and 21.0 ± 23.3 % (pre 15.0 ± 3.5; post 11.3 ± 2.1 ng/ml), respectively, with training, suggesting suppressed bone formation. OCN returned to baseline, while BAP remained suppressed 2-6 weeks post-training. TRAP5b significantly increased by 57.5 ± 51.6 % (pre 3.0 ± 0.9; post 4.6 ± 1.4 ng/ml) from pre- to post-training, suggesting increased bone resorption, and returned to baseline 2-6 weeks post-training. PTH Increased significantly by 37.3 ± 45.2 % with training. No changes in CTX, calcium, or PTH were detected. Conclusions: These data indicate that multi-stressor military training results in increased bone resorption and suppressed bone formation, with recovery of bone metabolism 2-6 weeks after completion of training. [ABSTRACT FROM AUTHOR]

Modern international military deployments in austere environments (i.e., Iraq and Afghanistan) place considerable physiological demands on soldiers. Significant physiological challenges exist: maintenance of physical fitness and body composition, rigors of external load carriage, environmental extremes (heat, cold, and altitude), medical illnesses, musculoskeletal injuries, traumatic brain injuries, post-traumatic stress disorder, and environmental exposure hazards (i.e., burn pits, vehicle exhaust, etc.). To date there is very little published research and no comprehensive reviews on the physiological effects of deployments. The purpose of this paper is to overview what is currently known from the literature related mainly to current military conflicts with regard to the challenges and consequences from deployments. Summary findings include: (1) aerobic capacity declines while muscle strength, power and muscular endurance appear to be maintained, (2) load carriage continues to tax the physical capacities of the Soldier, (3) musculoskeletal injuries comprise the highest proportion of all injury categories, (4) environmental insults occur from both terrestrial extremes and pollutant exposure, and (5) post-deployment concerns linger for traumatic brain injury and post-traumatic stress disorder. A full understanding of these responses will assist in identifying the most effective risk mitigation strategies to ensure deployment readiness and to assist in establishment of military employment standards. [ABSTRACT FROM AUTHOR]

Purpose: During US Army Basic Combat Training (BCT), graduation requirements, including physical readiness training (PRT), are standardized across training sites. However, there are concerns that the standardization may not be closely followed. Therefore, the purpose of this study was to measure and compare physical activity (PA) performed by recruits at 2 Army BCT sites. Methods: Twenty-four recruits per company from 11 companies (n=144 at Fort Jackson, SC; n=120 at Fort Sill, OK) wore an accelerometer and completed a daily PA log. The PA of one recruit from each company was recorded using an Army-developed direct observation tool (PAtracker). Amounts of time spent in various activity types, intensities, body positions, and in carrying external loads were obtained from the accelerometer, PA log, and PAtracker. Independent samples t tests were used to compare PA percentage time (%T) across training sites. Repeated measures analysis of variance was used to examine weekly differences in time spent in moderate to vigorous intensity PA during morning PRT. Results: Physical activity was measured for 47 days at Fort Jackson and 44 days at Fort Sill. Differences in the percentage of time spent in various physical activities between the 2 sites ranged from 0.4% to 15.3% (2.0-93.7 minutes). At Fort Jackson, time spent in moderate to vigorous PA during PRT significantly increased each week for the first 4 to 6 weeks of BCT. No difference was observed in PAtracker data between the 2 training sites in the percentage of time recruits spent in calisthenics (3.9%±3.6% vs 3.8%±3.0%, P=.700), and only a small difference was observed in percentage of time recruits spent running (1.2%±1.7% vs 1.6%±2.0%, P=.037). Conclusion: Army recruits at the 2 BCT sites spent similar amounts of time in each PA variable, regardless of the training site and measurement method. [ABSTRACT FROM AUTHOR]

Background: An understanding of the demands of physical activity (PA) during US Army Basic Combat Training (BCT) is necessary to support Soldier readiness and resilience. The purpose of this study was to determine the agreement among 3 different PA measurement instruments in the BCT environment. Methods: Twenty-four recruits from each of 11 companies wore an ActiGraph accelerometer (Actigraph, LLC, Pensacola, FL) and completed a daily PA log during 8 weeks of BCT at 2 different training sites. The PA of one recruit from each company was recorded using PAtracker, an Army-developed direct observation tool. Information obtained from the accelerometer, PA log, and PAtracker included time spent in various types of PA, body positions, PA intensities, and external loads carried. Pearson product moment correlations were run to determine the strength of association between the ActiGraph and PAtracker for measures of PA intensity and between the PAtracker and daily PA log for measures of body position and PA type. The Bland-Altman method was used to assess the limits of agreement (LoA) between the measurement instruments. Results: Weak correlations (r = -0.052 to r = 0.302) were found between the ActiGraph and PAtracker for PA intensity. Weak but positive correlations (r = 0.033 to r = 0.268) were found between the PAtracker and daily PA log for body position and type of PA. The 95% LoA for the ActiGraph and PAtracker for PA intensity were in disagreement. The 95% LoA for the PAtracker and daily PA log for standing and running and all PA types were in disagreement; sitting and walking were in agreement. Conclusions: The ActiGraph accelerometer provided the best measure of the recruits' PA intensity while the PAtracker and daily PA log were best for capturing body position and type of PA in the BCT environment. The use of multiple PA measurement instruments in this study was necessary to best characterize the physical demands of BCT. [ABSTRACT FROM AUTHOR]

The article discusses research which was conducted to investigate changes in creatine kinase (CK) and cortisol in national Collegiate Athletic Association division I American football players during a playing season. Researchers evaluated 22 players. They found that no significant changes in CK concentrations were observed over the season and that no changes in serum cortisol concentrations were observed.

The author discusses a study "Interleukin-6 responses to water immersion therapy after acute exercise heat stress: A Pilot Investigation," by Melinda Williams and colleagues. The results revealed that Whole-body cooling rates were greater in the cold water-bath condition as compared to warm and cold water-bath conditions. It concluded that cold water immersion related to IL-6 increased from post exercise values compared to warmer water-bath temperature, which hampered this increase.

The purpose of this study was to develop and validate a regression equation to estimate peak power (PP) using a large sample of athletic youths and young adults. Anthropometric and vertical jump ground reaction forces were collected from 460 male volunteers (age: 12–24 years). Of these 460 volunteers, a stratified random sample of 45 subjects representing 3 different age groups (12–15 years [n = 15], 16–18 years [n = 15], and 19–24 years [n = 15]) was selected as a validation sample. Data from the remaining 415 subjects were used to develop a new equation (“Novel”) to estimate PP using age, body mass (BM), and vertical jump height (VJH) via backward stepwise regression. Independently, age (r = 0.57), BM (r = 0.83), and VJ (r = 0.65) were significantly (p < 0.05) correlated with PP. However, age did not significantly (p = 0.53) contribute to the final prediction equation (Novel): PP (watts) = 63.6 × VJH (centimeters) + 42.7 × BM (kilograms) − 1,846.5 (r = 0.96; standard error of the estimate= 250.7 W). For each age group, there were no differences between actual PP (overall group mean ± SD: 3,244 ± 991 W) and PP estimated using Novel (3,253 ± 1,037 W). Conversely, other previously published equations produced PP estimates that were significantly different than actual PP. The large sample size used in this study (n = 415) likely explains the greater accuracy of the reported Novel equation compared with previously developed equations (n = 17–161). Although this Novel equation can accurately estimate PP values for a group of subjects, between-subject comparisons estimating PP using Novel or any other previously published equations should be interpreted with caution because of large intersubject error (± >600 W) associated with predictions. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the reliability of military-relevant tests designed to assess soldier readiness. Forty-seven soldiers (46 men, 1 woman; 22 +/- 3 years; 80.4 +/- 11.7 kg) performed each of seven soldier readiness tests on four different occasions over the course of 8 weeks. The soldier readiness tests were: (1) 3.2-km load carriage (LC) time-trial, (2) running long jump (RLJ), (3) one-repetition maximum box lift (1RMBL), (4) 10-minute repetitive box lift and carry (RBLC), (5) simulated victim rescue (VR), (6) mock grenade throw (GT) for accuracy, and (7) simulated combat rushes (CR). Repeated measures analysis of variance revealed significant learning effects for 1RMBL, RBLC, and GT; these tests required two (1RMBL and RBLC) or three (GT) trials to obtain statistically stable values. The intraclass correlation coefficient was 0.78 to 0.89 for all tests. LC, 1RMBL, RBLC, CR, and RLJ all demonstrated standard error of measurement values that were 3% to 5%, whereas VR and GT were 9% and 36%, respectively. In conclusion, the 1RMBL, RBLC, and GT tests required familiarization before a stable value was obtained. The LC, 1RMBL, RBLC, CR, and RLJ tests (and, to a lesser degree, the VR test) demonstrated reasonably acceptable levels of reliability and measurement error, whereas the GT test did not. [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted to compare the effects weightlifting and kettlebell training had on vertical jump, strength and body composition in 30 healthy men. Researchers found that while both exercise regimens increased strength and power, there was a larger increase in strength in those subjects who participated in weightlifting.

Development of core muscle strength and power to improve sport performance has been a controversial issue yielding mixed results. The purpose of this study was to investigate the relationship between two core field tests emphasizing power and measures of sport performance. Participants were twenty healthy, recreationally active males (age 23.40±1.88 yrs, height 174.63±5.81 cm, mass 76.08±7.67 kg). Participants were tested on four performance variables (40-yd sprint, shuttle run [5-10-5], vertical jump, and 1RM back squat) and two core field tests (front abdominal power throw [FAPT] and side abdominal power throw [SAPT]). Results demonstrated significant moderate correlations between the FAPT and 1RM back squat (r=.652) and relative back squat (r=.509). No other significant correlations were found. Results indicate that although the FAPT and SAPT tests are easy to perform in the field, most, but not all, performance measures were unrelated to core power. In order to properly assess the core and its role in human performance, it is necessary to evaluate sport-specific muscle actions and movements. [ABSTRACT FROM AUTHOR]

The article presents a study on the sprint running ability of collegiate women soccer players, which is used in evaluating the athletic potential of athletes. Methods used include electronic timing system, statistical analysis, and interclass correlation coefficient (ICC). Result shows that 30% of body weight assistance (BWA) with elastic cord helps in decreasing the sprint times in distance of 15 yards (yd).

The article presents a study which aims to compare the musculoskeletal effects of resistance exercise training using the Advanced Resistive Exercise Device (ARED) with the results of training with free weight (FW). It notes that musculoskeletal effects resulting from ARED exercise were not different in a significant manner to the effects of training with FW. It concludes that ARED training will be a more effective countermeasure than interim Resistive Exercise Device (iRED) training for spaceflight-induced deconditioning.

The purpose of this study is to evaluate the effectiveness of aerobic endurance (E), strength (R), and combined endurance and strength (CB) training for improving performance of tactical occupational tasks and determine if combined training interferes with performance enhancements of E or R alone. A total of 56 recreationally active women were randomly placed into four groups: R (n = 18), E (n = 13), CB (n = 15), Control (n = 10). Subjects trained three non-consecutive days per week for 8 weeks. Performance was measured pre-, mid-, and post-training for bench press one-repetition maximum (1-RM), squat 1-RM, bench press throw and squat jump peak power, VO2peak, 3.2 km load carriage (LC), 3.2 km run (run), and repetitive lift and carry (RLC). R and E demonstrated improvements which were generally specific to their training. R improved squat (48.3%) and bench press 1-RM (23.8%), bench press throw (41.9%), RLC (31.3%), and LC (11.5%). E improved run (14.7%), VO2peak (6.2%), squat 1-RM (15.3%), LC (12.9%), and RLC (22.5%). CB improved squat (37.6%) and bench press 1-RM (20.9%), bench press throw (39.6%), VO2peak (7.6%), run (10.4%), LC (13.1%), and RLC (45.5%). Post-training 1-RM squat was greater in R and CB than E, while E completed the 3.2 km load carriage task faster than C. In conclusion, 8 weeks of combined training improved performance in all tactical occupational tasks measured and did not interfere with improvements in strength, power and endurance measures compared to R or E alone. [ABSTRACT FROM AUTHOR]

The article presents the results of a study which investigated the relationship between swim sprints and throwing ability in female college water polo athletes. Details of the experimental protocol are presented. It was found that repeated swim sprints did not impair throwing accuracy, but did significantly reduce velocity.

The article reports on research conducted to investigate existing relationships between off-ice performance measures and on-ice performance quantified by speed and acceleration in figure skaters. Researchers evaluated 27 women college figure skaters. They found that slide board stride count was best for predicting on-ice speed and acceleration, that the vertical jump height test was the second best predictor and that the best predictors of single lap speed were the slide board and 40 yard dash.

Abstract: Prescribing exercise based on intensity, frequency, and duration of loading may maximize osteogenic responses in bone, but a model of the osteogenic potential of exercise has not been established in humans. In rodents, an osteogenic index (OI) has been used to predict the osteogenic potential of exercise. The current study sought to determine whether aerobic, resistance, or combined aerobic and resistance exercise programs conducted over eight weeks and compared to a control group could produce changes in biochemical markers of bone turnover indicative of bone formation. We further sought to determine whether an OI could be calculated for each of these programs that would reflect observed biochemical changes. We collected serum biomarkers [bone-specific alkaline phosphatase (BAP), osteocalcin, tartrate-resistant acid phosphatase (TRAP), C-terminal telopeptide fragment of type I collagen (CTx), deoxypyridinoline (DPD), 25-hydroxy vitamin D (25(OH)D), and parathyroid hormone (PTH)] in 56 women (20.3±1.8 years) before, during and after eight weeks of training. We also measured bone mineral density (BMD) at regional areas of interest using DXA and pQCT. Biomarkers of bone formation (BAP and osteocalcin) increased in the Resistance and Combined groups (p <0.05), while biomarkers of bone resorption (TRAP and DPD) decreased and increased, respectively, after training (p <0.05) in all groups. Small changes in volumetric and areal BMD (p <0.05) were observed in the distal tibia in the Aerobic and Combined groups, respectively. Mean weekly OIs were 16.0±1.9, 20.6±2.2, and 36.9±5.2 for the Resistance, Aerobic, and Combined groups, respectively. The calculated osteogenic potential of our programs did not correlate with the observed changes in biomarkers of bone turnover. The results of the present study demonstrate that participation in an eight week physical training program that incorporates a resistance component by previously inactive young women results in alterations in biomarkers of bone remodeling indicative of increased formation without substantial alterations in markers of resorption. [Copyright &y& Elsevier]

The article presents a study which examines the effects Muscle Armor™ (MA) from Abbott laboratories Inc. in Abbott Park, Illinois on hormonal and damage markers when added to a 12-week resistance exercise training program. It notes that the essential amino-acid based formula contains β-hydroxy-β-methylbutyrate (HMB). Previous research shows induced anabolic effects through intake of essential amino acids and their metabolites. MA supplementation can increase gains in muscle strength, lean body mass, and muscle power after resistance training exercise. MA also increases testosterone induced during resting and exercise phase, as well as concentrations of resting growth hormone. However, MA reduces concentrations of preexercise cortisol.