Comprehensive Physical Activity Assessment During U.S. Army Basic Combat Training.

Alemany, JA, Pierce, JR, Bornstein, DB, Grier, TL, Jones, BH, and Glover, SH. Comprehensive physical activity assessment during U.S.

Growth Hormone and Insulin-like Growth Factor-I Molecular Weight Isoform Responses to Resistance Exercise Are Sex-Dependent.

To determine if acute resistance exercise-induced increases in growth hormone (GH) and insulin-like growth factor-I (IGF-I) were differentially responsive for one or more molecular weight (MW) isoforms and if these responses were sex-dependent. College-aged men ( = 10) and women ( = 10) performed an acute resistance exercise test (ARET; 6 sets, 10 repetition maximum (10-RM) squat, 2-min inter-set rest). Serum aliquots from blood drawn Pre-, Mid-, and Post-ARET (0, +15, and +30-min post) were processed using High Performance Liquid Chromatography (HPLC) fractionation and pooled into 3 MW fractions (Fr.

Sex and age differences in physical performance: A comparison of Army basic training and operational populations.

Objectives: To determine the age- and sex-specific differences of physical fitness performances and Body Mass Index (BMI) in basic training and the operational Army.

Design: Cross-sectional Study.

Methods: This secondary analysis utilizes retrospective surveys of U.

Functional Movement Screen: Pain versus composite score and injury risk.

Objectives: The Functional Movement Screen (FMS™) has been used as a screening tool to determine musculoskeletal injury risk using composite scores based on movement quality and/or pain. However, no direct comparisons between movement quality and pain have been quantified.

Design: Retrospective injury data analysis.

Differential basal and exercise-induced IGF-I system responses to resistance vs. calisthenic-based military readiness training programs.

Objective: The purpose of this study was to: 1) evaluate differential responses of the IGF-I system to either a calisthenic- or resistance exercise-based program and 2) determine if this chronic training altered the IGF-I system during an acute resistance exercise protocol.

Design: Thirty-two volunteers were randomly assigned into a resistance exercise-based training (RT) group (n=15, 27±5y, 174±6cm, 81±12kg) or a calisthenic-based training group (CT) (n=17, 29±5y, 179±8cm, 85±10kg) and all underwent 8weeks of exercise training (1.5h/d, 5d/wk).

Twenty-hour growth hormone secretory profiles after aerobic and resistance exercise.

Introduction: The pulsatile secretion pattern of growth hormone (GH) is an important parameter of GH action at peripheral tissues, and more information is needed on how exercise impacts GH secretion. This study hypothesized that both aerobic and resistance exercise would exhibit dose-response relationships with respect to exercise duration and 20-h postexercise GH secretion.

Methods: Eight healthy men randomly completed five separate conditions: 1) control (no exercise; CON), 2) a moderate-duration (1-h) aerobic exercise session (MA), 3) a long-duration (2-h) aerobic exercise session (LA), 4) a moderate-duration (1-h) resistance exercise session (MR), and 5) a long-duration (2-h) resistance exercise session (LR).

Exercise-induced insulin-like growth factor I system concentrations after training in women.

Introduction: This study examined the effects of short-term physical training on the acute hormonal response (i.e., growth hormone, total and free insulin-like growth factor I [IGF-I], and IGF binding proteins [IGFBP]-1, IGFBP-2, and IGFBP-3) to resistance exercise (RE) in women.

Circulating bioactive and immunoreactive IGF-I remain stable in women, despite physical fitness improvements after 8 weeks of resistance, aerobic, and combined exercise training.

Insulin-like growth factor-I (IGF-I) is regulated by a number of IGF-binding proteins (IGFBPs) and proteases that influence IGF-I bioactivity. A specific IGF-I kinase receptor activation assay (KIRA) has been developed that determines the ability of IGF-I to activate the IGF-I receptor by quantification of intracellular receptor autophosphorylation on IGF-I binding. KIRA-assessed IGF-I bioactivity has not been utilized within the context of chronic exercise training paradigms.

Combined resistance and endurance training improves physical capacity and performance on tactical occupational tasks.

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.

Diet, body composition, and physical fitness influences on IGF-I bioactivity in women.

Objective: Insulin-like growth factor I (IGF-I) is a metabolic-regulatory hormone that mediates a variety of physiologic functions. Body composition, fitness status and intake of certain micro- and macronutrients are associated with circulating concentrations of immunoreactive IGF-I. The influence of these factors on IGF-I bioactivity; however, is undetermined.

Effects of exercise mode and duration on 24-h IGF-I system recovery responses.

Introduction: This study hypothesized that insulin-like growth factor-binding protein (IGFBP), rather than insulin-like growth factor I (IGF-I) itself, would be more responsive to acute exercise stress in a dose-dependent fashion.

Methods: Eight men (24 +/- 5 yr, 87 +/- 9 kg, 182 +/- 6 cm, 21 +/- 5% body fat) had blood drawn every 4 h after exercise for 24 h and assayed for IGF-I, IGFBP-1, -3, -6, the acid labile subunit (ALS), insulin, glucose, and nonesterified free fatty acids on five occasions: no exercise (control, C), moderate-duration resistance exercise (MDRE; 25, 5-10 repetition maximum (RM) sets), long-duration resistance exercise (LDRE; 50, 5-10 RM sets), moderate-duration aerobic exercise (MDAE; three 15-min cycling bouts at approximately 70% (.)VO2peak), and long-duration aerobic exercise (LDAE; six 15-min cycling bouts at approximately 70% (.

Effects of exercise training on the matrix metalloprotease response to acute exercise.

Matrix metalloproteases (MMPs) in the circulation are thought to modulate the activation of growth factors, cytokines, and angiogenesis, facilitating physiological adaptations to exercise training. The purpose of this work was to characterize serum MMP-1, MMP-2, MMP-3, and MMP-9 concentrations pre- and post-eight weeks of exercise training. We tested the hypothesis that exercise training would influence serum MMP concentrations in response to an acute resistance exercise test (ARET).

Effects of acute and chronic exercise on disulfide-linked growth hormone variants.

Purpose: To test the hypothesis that the appearance of disulfide-linked growth hormone (GH) aggregates during and after an acute resistance exercise test (ARET) in men could be influenced by chronic physical training.

Methods: Fourteen men (28 +/- 1 yr) underwent two different 8-wk physical training programs designed to improve military performance. Before and after chronic training, subjects performed an ARET (six sets of 10 repetition-maximum squat) and had venous blood drawn pre-, mid-, and post-ARET (0, 15, and 30 min postexercise).

Effects of two different eight-week training programs on military physical performance.

Various physical demands are placed on soldiers, whose effectiveness and survivability depend on their combat-specific physical fitness. Because sport training programs involving weight-based training have proven effective, this study examined the value of such a program for short-term military training using combat-relevant tests. A male weight-based training (WBT) group (n = 15; mean +/- SD: 27.

Effects of dietary protein content on IGF-I, testosterone, and body composition during 8 days of severe energy deficit and arduous physical activity.

Energy restriction coupled with high energy expenditure from arduous work is associated with an altered insulin-like growth factor-I (IGF-I) system and androgens that are coincident with losses of fat-free mass. The aim of this study was to determine the effects of two levels of dietary protein content and its effects on IGF-I, androgens, and losses of fat-free mass accompanying energy deficit. We hypothesized that higher dietary protein content would attenuate the decline of anabolic hormones and, thus, prevent losses of fat-free mass.

Prediction of simulated battlefield physical performance from field-expedient tests.

Predictive models of battlefield physical performance can benefit the military. To develop models, 32 physically trained men (mean +/- SD: 28.0 +/- 4.

Physiological consequences of U.S. Army Ranger training.

Purpose: Soldiers are expected to maintain a high degree of physical readiness as operational demands can severely degrade performance capabilities. This study examined the physiological consequences of U.S.

Energy flux, more so than energy balance, protein intake, or fitness level, influences insulin-like growth factor-I system responses during 7 days of increased physical activity.

The purpose of this study was to determine the impact of dietary factors and exercise-associated factors on the response of IGF-I and its binding proteins (IGFBPs) during a period of increased physical activity. Twenty-nine men completed a 4-day (days 1-4) baseline period of a controlled energy balanced diet while maintaining their normal physical activity level followed by 7 days (days 5-11) of a 1,000 kcal/day increase in physical activity above their normal activity levels. Two subject groups, one sedentary (Sed, mean Vo(2peak): 39 mlxkg(-1)xmin(-1), n = 7) and one fit (FIT1, mean Vo(2peak): 56 ml.

Utility of circulating IGF-I as a biomarker for assessing body composition changes in men during periods of high physical activity superimposed upon energy and sleep restriction.

Insulin-like growth factor (IGF)-I is a biomarker that may have greater utility than other conventional nutritional biomarkers in assessing nutritional, health, and fitness status. We hypothesized that the IGF-I system would directionally track a short-term energy deficit and would be more related to changes in body composition than other nutritional biomarkers. Thirty-five healthy men (24 +/- 0.

Minimally invasive sampling of transdermal body fluid for the purpose of measuring insulin-like growth factor-I during exercise training.

Insulin-like growth factor-I (IGF-I) is a ubiquitous hormone that is secreted in both an endocrine and an autocrine/paracrine manner. IGF-I has conventionally been measured in serum; however, transdermal body fluid (TDF) remains as an unexplored biocompartment in which IGF-I also resides and may be more biologically relevant because of its proximity to tissues and cells. The purpose of this study was to compare IGF-I in serum versus IGF-I in TDF before and after 8 weeks of physical training.

Reliability assessment of ballistic jump squats and bench throws.

The purpose of this investigation was to determine the test-retest reliability and coefficient of variation of 2 novel physical performance tests. Ten healthy men (22.0 +/- 3.

Measurement of insulin-like growth factor-I during military operational stress via a filter paper blood spot assay.

Insulin-like growth factor-I (IGF-I) is sensitive to nutritional stress and is reduced in soldiers during stressful field training. Methods have recently been developed to measure IGF-I from filter paper blood spots. Filter paper has advantages over traditional blood sampling in that neither blood separation equipment nor refrigeration is necessary after sample collection.