Validity of laboratory and field methods for predicting fat free mass in elite male rowers

The purpose of this study was to determine the validity of air displacement plethysmography, ultrasound, near-infrared interactance, and skinfold measurements in estimating fat-free mass in elite male rowers. Twenty-three elite-level male rowers participated in this investigation. All participants were members of the High Performance Training Center located in Oklahoma City, OK and had a minimum of 4 years of training experience. All body composition assessments were performed on the same day in no particular order, except for hydrostatic weighing (HW), which was measured last. All participants were asked to refrain from food 8 to 12 hours prior to testing (ad libitum water intake was allowed up to one hour prior to testing), and were instructed to avoid exercise for at least twenty-four hours prior to testing. Hydration status was determined prior to all testing using specific gravity via handheld refractometry to ensure proper hydration prior to testing. Fat-free mass (FFM) was evaluated using the four compartment model (4C), which included the measures of total body water (TBW) from bioimpedance spectrospcy (BIS), body volume from hydrostatic weighing (HW), and total body bone mineral (TBBM) via dual energy x-ray absorptiometry (DEXA). Estimates of FFM via air displacement plethysmography (BOD POD®), near infrared interactance (Futrex® 6100/XL), ultrasound (IntelaMetrix BX-2000), and the 3-site Jackson and Pollock skinfold equation (Sum3) were validated against the criterion method, 4C model. The major findings of the study were that all independent techniques evaluated overestimated FFM and should not be considered valid for the assessment of FFM in elite male rowers. Future studies should use multiple compartment models for the estimation of FFM, and include the measurement of TBW and TBBM

Motives for Physical Activity and Physiological Variables as Predictors of Exercise Intentions Following a High Intensity Interval Training Protocol in College-Age Females

International Journal of Exercise Science 9(2): 121-135, 2016. More females are classified as insufficiently active and may have little time for physical activity than males (28). Sufficient activity for adults includes a minimum of 30 minutes of moderate intensity aerobic exercise, five days per week or 20 minutes of vigorous intensity exercise three days per week, or a combination of these, in addition to the resistance training recommendation of training each muscle group two times per week (14). High intensity interval training (defined as very short intense intervals, usually above 85% maximum heart rate accompanied by alternated passive recovery periods; HIIT) has become a popular alternative to the more traditional continuous training utilized by individuals due to its time efficiency. In fact, HIIT has been shown to induce many of the same physiological changes as moderate intensity training with less training time. It is possible that college-aged females may benefit from HIIT and its inherent time-saving qualities. To test this hypothesis, this study sought to determine the influence of a HIIT protocol on general motives for being physically active and intentions for future HIIT participation. Participants included sixty-five female students between the ages 18 and 25 who were enrolled in a physical activity class that included HIIT as a part of the curriculum. Physiological responses to the HIIT protocol were measured via exercise intensity and calories burned, while motives and intentions were measured through questionnaires. Results revealed no changes in any variables over the course of the study with the exception of blood pressure. Fitness was the only variable that significantly predicted intentions for exercise and thus future HIIT participation. These psychologically oriented results show some promise for the use of HIIT in this population. In order to promote long-term adherence to exercise programs, the nature of the relationship between motives and intentions call for future studies to determine why more intrinsic motives, including competence, were not related to intentions to HIIT

The acute neuromuscular responses to cluster set resistance training: A systematic review and meta-analysis

Background: Cluster sets (CSs) are a popular resistance training (RT) strategy categorised by short rest periods implemented between single or groups of repetitions. However, evidence supporting the effectiveness of CSs on acute intra-session neuromuscular performance is still equivocal. Objective: The objective of this investigation was to determine the efficacy of a single session of CSs to attenuate losses in force, velocity and power compared to traditional set (TS) training. Methods: Screening consisted of a systematic search of EMBASE, Google Scholar, PubMed, Scopus and SPORTDiscus. Inclusion criteria were (1) measured one or more of mean/peak force, velocity or power; (2) implemented CSs in comparison to TSs; (3) an acute design, or part thereof; and (4) published in an English-language, peer-reviewed journal. Raw data (mean ± standard deviation) were extracted from included studies and converted into standardised mean differences (SMDs) and ± 95% confidence intervals (CIs). Results: Twenty-five studies were used to calculate SMD ± 95% CI. Peak (SMD = 0.815, 95% CI 0.105–1.524, p = 0.024) and mean (SMD = 0.863, 95% CI 0.319–1.406, p = 0.002) velocity, peak (SMD = 0.356, 95% CI 0.057–0.655, p = 0.019) and mean (SMD = 0.692, 95% CI 0.395–0.990, p \u3c 0.001) power, and peak force (SMD = 0.306, 95% CI − 0.028 to 0.584, p = 0.031) favoured CS. Subgroup analyses demonstrated an overall effect for CS across loads (SMD = 0.702, 95% CI 0.548–0.856, p \u3c 0.001), included exercises (SMD = 0.664, 95% CI 0.413–0.916, p \u3c 0.001), experience levels (SMD = 0.790, 95% CI 0.500–1.080, p \u3c 0.001) and CS structures (SMD = 0.731, 95% CI 0.567–0.894, p \u3c 0.001) with no difference within subgroups. Conclusion: CSs are a useful strategy to attenuate the loss in velocity, power and peak force during RT and should be used to maintain neuromuscular performance, especially when kinetic outcomes are emphasised. However, it remains unclear if the benefits translate to improved performance across all RT exercises, between sexes and across the lifespan

The acute neuromuscular responses to cluster set resistance training: A systematic review and meta-analysis

Background: Cluster sets (CSs) are a popular resistance training (RT) strategy categorised by short rest periods implemented between single or groups of repetitions. However, evidence supporting the effectiveness of CSs on acute intra-session neuromuscular performance is still equivocal. Objective: The objective of this investigation was to determine the efficacy of a single session of CSs to attenuate losses in force, velocity and power compared to traditional set (TS) training. Methods: Screening consisted of a systematic search of EMBASE, Google Scholar, PubMed, Scopus and SPORTDiscus. Inclusion criteria were (1) measured one or more of mean/peak force, velocity or power; (2) implemented CSs in comparison to TSs; (3) an acute design, or part thereof; and (4) published in an English-language, peer-reviewed journal. Raw data (mean ± standard deviation) were extracted from included studies and converted into standardised mean differences (SMDs) and ± 95% confidence intervals (CIs). Results: Twenty-five studies were used to calculate SMD ± 95% CI. Peak (SMD = 0.815, 95% CI 0.105–1.524, p = 0.024) and mean (SMD = 0.863, 95% CI 0.319–1.406, p = 0.002) velocity, peak (SMD = 0.356, 95% CI 0.057–0.655, p = 0.019) and mean (SMD = 0.692, 95% CI 0.395–0.990, p \u3c 0.001) power, and peak force (SMD = 0.306, 95% CI − 0.028 to 0.584, p = 0.031) favoured CS. Subgroup analyses demonstrated an overall effect for CS across loads (SMD = 0.702, 95% CI 0.548–0.856, p \u3c 0.001), included exercises (SMD = 0.664, 95% CI 0.413–0.916, p \u3c 0.001), experience levels (SMD = 0.790, 95% CI 0.500–1.080, p \u3c 0.001) and CS structures (SMD = 0.731, 95% CI 0.567–0.894, p \u3c 0.001) with no difference within subgroups. Conclusion: CSs are a useful strategy to attenuate the loss in velocity, power and peak force during RT and should be used to maintain neuromuscular performance, especially when kinetic outcomes are emphasised. However, it remains unclear if the benefits translate to improved performance across all RT exercises, between sexes and across the lifespan

Utilization of an Anti-gravity Treadmill in a Physical Activity Program with Female Breast Cancer Survivors: a Pilot Study

International Journal of Exercise Science 9(1): 101- 109, 2016. Breast Cancer survivors can experience a myriad of physical and psychological benefits as a result of regular exercise. This study aimed to build on previous research using lower impact exercise programs by using an anti-gravity (Alter-G®) treadmill to administer cardiovascular training. The purpose of this study was to determine the effectiveness a physical activity program, including an Alter-G® treadmill, for improving physiological and psychosocial measures in female breast cancer survivors. A 14-week intervention using an AB-AB study design was employed. Six female breast cancer survivors were recruited to participate in the study. Participants attended three 60-minute sessions per week, consisting of a combination of muscular strength/endurance, and cardiovascular endurance exercises. Consistent with current literature and guidelines, exercise interventions were individualized and tailored to suit individuals. Data was collected and analyzed in 2013. Visual inspection of results found improvements in cardiovascular endurance and measures of body composition. Quality of life was maintained and in some cases, improved. Finally, no adverse effects were reported from the participants, and adherence to the program for those who completed the study was 97%. The results of this study suggest that the use of a physical activity program in combination with an Alter-G® treadmill may provide practical and meaningful improvements in measures of cardiovascular endurance and body composition

Absolute and Relative Strength, Power and Physiological Characteristics of Indian Junior National-Level Judokas

The physical qualities that underpin successful junior judokas requires continuing investigation. We investigated the physical and physiological characteristics of junior national level judokas. We tested 25 (15 male, 10 female) Indian judokas for absolute and relative strength (back-squat and bench-press one-repetition maximum (1RM) as well as isometric handgrip), aerobic (RAMP test) and lower-body anaerobic power (Wingate 6-s sprint and countermovement jump), change-of-direction (5-0-5 test) and speed (30 m sprint). Athletes were grouped according to national-level competition placing (gold-medal winners (GM; n = 8), all medal winners (MW; n = 13), non-medallists (NM; n = 12), and NM plus silver and bronze; all others (AO; n = 17)). Stepwise discriminant function analysis determined characteristics likely to predict successful performance. Independent t-tests and effect size (Hedge’s g) analyses were performed between groups. GM demonstrated greater lower-body absolute (20.0%; g = 0.87, p = 0.046) and relative 1RM strength (21.0%; g = 0.87, p = 0.047), and greater lower-body absolute (25.4%; g=1.32, p=0.004) and relative (27.3%; g = 1.27, p = 0.005) anaerobic power compared to AO. Furthermore, anaerobic power can correctly predict 76.5% and 62.5% of AO and GM athletes, respectively. No differences were observed between MW and NM groups. The results suggest the importance of lower-body strength and power for junior national-level judokas and provides information for professionals working with these athletes

The agreement between a portable contact-mat and force-plates during bilateral vertical jumps

Force plates are commonly used when assessing vertical jumping performance but are not always affordable or practical tools for all testing situations. Twenty-four participants volunteered to take part in a study investigating the agreement between bilateral force plates and a new commercially available contact mat that records jump height, flight-time (FT), and FT of individual limbs during both countermovement (CMJ) and squat (SJ) jumps. Each participant performed six jumps of each type while standing on a contact mat placed upon a pair of in-ground force plates. When compared to the force plate via ordinary least products regression, the contact mat agreed with force plate CMJ and SJ jump height, individual limb FT during CMJs, and left-leg FT during SJs. The bilateral contact mat provided valid assessment of individual limb FT during CMJs, but not SJs. Practitioners can therefore use a bilateral contact mat interchangeably with bilateral force plates to measure SJ and CMJ performance

Effects of spaceflight on musculoskeletal health: A systematic review and meta-analysis, considerations for interplanetary travel

Background: If interplanetary travel is to be successful over the coming decades, it is essential that countermeasures to minimize deterioration of the musculoskeletal system are as effective as possible, given the increased duration of spaceflight associated with such missions. The aim of this review, therefore, is to determine the magnitude of deconditioning of the musculoskeletal system during prolonged spaceflight and recommend possible methods to enhance the existing countermeasures. Methods: A literature search was conducted using PubMed, Ovid and Scopus databases. 5541 studies were identified prior to the removal of duplicates and the application of the following inclusion criteria: (1) group means and standard deviations for pre- and post-spaceflight for measures of strength, muscle mass or bone density were reported (or provided by the corresponding author when requested via e-mail), (2) exercise-based countermeasures were included, (3) the population of the studies were human, (4) muscle function was assessed and (5) spaceflight rather than simulated spaceflight was used. The methodological quality of the included studies was evaluated using a modified Physiotherapy Evidence Database (PEDro) scale for quality, with publication bias assessed using a failsafe N (Rosenthal method), and consistency of studies analysed using I2 as a test of heterogeneity. Secondary analysis of studies included Hedges’ g effect sizes, and between-study differences were estimated using a random-effects model. Results: A total of 11 studies were included in the meta-analyses. Heterogeneity of the completed meta-analyses was conducted revealing homogeneity for bone mineral density (BMD) and spinal muscle size (Tau2 \u3c 0.001; I2 = 0.00%, p \u3e 0.05), although a high level of heterogeneity was noted for lower body force production (Tau2 = 1.546; I2 = 76.03%, p \u3c 0.001) and lower body muscle mass (Tau2 = 1.386; I2 = 74.38%, p \u3c 0.001). The estimated variance ( ≤ -0.306) for each of the meta-analyses was significant (p ≤ 0.033), for BMD (− 0.48 to − 0.53, p \u3c 0.001), lower body force production (− 1.75, p \u3c 0.001) and lower body muscle size (− 1.98, p \u3c 0.001). Spaceflight results in small reductions in BMD of the femur (Hedges g = − 0.49 [− 0.69 to – 0.28]), trochanter (Hedges g = − 0.53 [− 0.77 to – 0.29]), and lumbo-pelvic region (Hedges g = − 0.48 [− 0.73 to – 0.23]), but large decreases in lower limb force production (Hedges g = − 1.75 [− 2.50 to – 0.99]) and lower limb muscle size (Hedges g = − 1.98 [− 2.72 to – 1.23]). Conclusions: Current exercise countermeasures result in small reductions in BMD during long-duration spaceflight. In contrast, such exercise protocols do not alleviate the reductions in muscle function or muscle size, which may be attributable to the low to moderate loads reported by crewmembers and the interference effect associated with concurrent training. It is recommended that higher-load resistance exercise and the use of high-intensity interval training should be investigated, to determine if such modifications to the reported training practices result in more effective countermeasures to the deleterious effect of long-duration spaceflight on the muscular system

Effects of resistance training on classic and specific bioelectrical impedance vector analysis in elderly women

Raw bioelectrical impedance analysis (BIA) data [resistance (R); reactance (Xc)] through bioelectrical impedance vector analysis (BIVA) and phase angle (PhA) have been used to evaluate cellular function and hydration status. The purpose of this investigation was to examine the effects of resistance training (RT) on classic and specific BIVA in elderly women. Twenty women (mean ± SD; age: 71.9 ± 6.9 years; BMI: 24.5 ± 3.0 kg m(-2)) completed a 6-month RT program. Whole-body, single-frequency BIA, body geometry, and leg strength (5RM) measures were completed at baseline (t0), 3 months (t3), and 6 months (t6). The mean impedance vector displacements were compared using Hotelling's T(2) test to evaluate changes in R and Xc relative to height (R/ht; Xc/ht) or body volume (Rsp; Xcsp) estimated from the arms, legs, and trunk. 5RM, PhA, and BIVA variables were compared using ANOVA. PhA improved at t6 (p < 0.01), while 5RM improved at t3 and t6 (p < 0.01). Using classic BIVA, 6 months (T(2) = 31.6; p < 0.01), but not 3 months of RT (T(2) = 4.5; p = 0.20), resulted in significant vector migration. Using specific BIVA, 6 months (T(2) = 24.4; p < 0.01), but not 3 months of RT (T(2) = 5.5; p = 0.10), also resulted in significant vector migration. 5RM was correlated to both PhA (r = 0.48-56) and Xcsp (r = 0.45-53) at all time points. Vector displacements were likely the result of improved cellular integrity (Xcsp) and cellular health (PhA)