The Effects of Creatine Monohydrate Loading on Exercise Recovery in Active Women throughout the Menstrual Cycle.

Creatine supplementation improves anaerobic performance and recovery; however, to date, these outcomes have not been well explored in females. This study evaluated the effect of creatine monohydrate loading on exercise recovery, measured by heart rate variability (HRV) and repeated sprint performance, in women across the menstrual cycle. In this randomized, double-blind, cross-over study, 39 women (mean ± standard deviation: age: 24.6 ± 5.9 years, height: 172.5 ± 42.3 cm, weight: 65.1 ± 8.1 kg, BF: 27.4 ± 5.8%) were randomized to a creatine monohydrate (n = 19; 20 g per day in 4 × 5 g doses) or non-caloric PL group (n = 20). HRV was measured at rest and after participants completed a repeated sprint cycling test (10 × 6 s maximal sprints). Measurements were conducted before and after supplementation in the follicular/low hormone and luteal/high hormone phases. Creatine monohydrate supplementation did not influence HRV values, as no significant differences were seen in HRV values at rest or postexercise. For repeated sprint outcomes, there was a significant phase × supplement interaction (p = 0.048) for fatigue index, with the greatest improvement seen in high hormone in the creatine monohydrate group (-5.8 ± 19.0%) compared to changes in the PL group (0.1 ± 8.1%). Sprint performance and recovery were reduced by the high hormone for both groups. Though not statistically significant, the data suggests that creatine monohydrate could help counteract performance decrements caused by the high hormone. This data can help inform creatine monohydrate loading strategies for females, demonstrating potential benefits in the high hormone phase.

Menopause Transition: A Cross-Sectional Evaluation on Muscle Size and Quality.

INTRODUCTION: The menopause transition yields significant physiological alterations. The purpose was to characterize lean soft tissue (LST), muscle size (muscle cross-sectional area (mCSA)), muscle quality (echo intensity (EI)), and strength across the menopause transition. A secondary aim was to evaluate whole-body protein turnover in a subsample of women. METHODS: Seventy-two healthy women were enrolled in this cross-sectional study based on menopause stage (PRE: n = 24; PERI: n = 24; POST: n = 24). Whole-body LST was measured via dual-energy x-ray absorptiometry, and muscle characteristics (mCSA and EI) were measured via B-mode ultrasound of the vastus lateralis. Maximal voluntary contractions (N·m) of the knee extensors were evaluated. Physical activity (in minutes per day) was accounted for using the International Physical Activity Questionnaire. A subsample of women ( n = 27) ingested 2.0 g of 15 N-alanine to determine whole-body net protein balance (NB; in grams per kilogram of body mass per day). RESULTS: Significant differences were evident in LST ( P = 0.022), leg LST ( P = 0.05), and EI ( P = 0.018) between menopause stages. Bonferroni post-hoc comparisons revealed greater LST in PRE versus PERI (mean difference (MD) ± SE, 3.8 ± 1.5 kg; P = 0.048) and POST (3.9 ± 1.5 lb; P = 0.049). Similarly, EI was significantly higher in PERI PRE (MD, 18.3 ± 7.1 a.u.; P = 0.036). There was no significant difference in mCSA ( P = 0.082) or in maximal voluntary contraction ( P = 0.167). NB was significantly different across groups ( P = 0.026); NB was greater in PRE compared with PERI (MD, 0.39 ± 0.17 g·kg -1 ; P = 0.090), and from PRE to POST (MD, 0.46 ± 0.17 g·kg -1 ; P = 0.042). Physical activity was not significantly different across groups but demonstrated a linear increase from PRE to POST. CONCLUSIONS: The current findings suggest that LST, muscle quality, and protein balance may be negatively influenced by the menopause transition.

A Randomized Controlled Trial of Changes in Fluid Distribution across Menstrual Phases with Creatine Supplementation.

This study examined the effects of creatine (Cr) loading on body mass (BM) and fluid markers of total body water (TBW), extra-cellular fluid (ECF), and intra-cellular fluid (ICF) across the menstrual cycle (MC). Thirty moderately active females, either naturally-menstruating (NM) or using hormonal contraceptives (HC), were randomized to Cr (Cr; 4 × 5 g/day of creatine monohydrate for 5 days; n = 15) or a non-caloric placebo (PL; n = 15) using a double-blind, placebo-controlled design, with a menstrual phase crossover. BM, TBW, ECF, and ICF were measured at pre- and post-supplementation in randomized order of follicular phase (FP; NM: MC days 0−8, HC: inactive pill days) or luteal phase (LP; NM: ≤15 days from next projected cycle start date, HC: active pill days) using bioelectrical impedance spectroscopy. Acute hydration status and salivary estrogen were used as covariates. Change in BM was not different between groups across MC ([PL-Cr] Δ 0.40 ± 0.50 kg; p = 0.427) or between MC phase across groups ([FP-LP] Δ 0.31 ± 0.48 kg; p = 0.528). TBW (p = 0.802), ECF (p = 0.373), and ICF (p = 0.795) were not different between supplement groups at pre-supplementation/FP time points. There were no significant differences between the NM and HC subjects at any time point, for any outcome (p > 0.05). Following LP supplementation, significant changes were observed in TBW (Cr: Δ 0.83 ± 0.38 L, PL: Δ −0.62 ± 0.38 L; p = 0.021), ECF (Cr: Δ 0.46 ± 0.15 L, PL: Δ −0.19 ± 0.15 L; p = 0.013), and ICF (Cr: Δ 0.74 ± 0.23 L, PL: Δ −0.02 ± 0.23 L; p = 0.041). These data demonstrate an increase in all fluid compartments in the LP following Cr loading, without observed alterations in body weight for females.

Evaluation of pre-workout and recovery formulations on body composition and performance after a 6-week high-intensity training program.

Introduction: Activities such as high-intensity resistance training (HIRT) and high-intensity interval training (HIIT) may be more time-efficient modes to stimulate rapid changes in performance and body composition. There is little research evaluating the combined effects of HIRT and HIIT on body composition and strength, particularly when paired with nutritional supplementation. Purpose: To evaluate the chronic effects of pre- and post-workout supplementation on body composition and strength, and to understand sex-specific responses. Materials and methods: 64 untrained males (n = 23) and females (n = 41) (mean ± standard deviation; age: 33.2 ± 10.0 years; %fat: 31.6 ± 7.4%) were randomized to either (1) pre-post supplementation [SUP (n = 25); pre = multi-ingredient caffeine/HMB/vit D; post = whey protein/carbohydrates/glucosamine/vitamins], (2) placebo [PL (n = 24); non-caloric], or (3) control [CON (n = 15)]. All participants completed one repetition max (1RM) strength testing for leg press and bench press at baseline and week 6. Estimates of fat mass (FM) and lean mass (LM) were measured via dual energy x-ray absorptiometry. Participants in the SUP or PL group completed a 6-week supervised exercise intervention consisting of a full-body HIRT workout (3 × 6-8 reps) followed by a HIIT treadmill run (6 × 1 min run: 1 min rest) twice per week. Outcomes were evaluated by separate repeated measure ANOVAs (2 × 3). Results: There were no differences in FM between groups or sex (p = 0.133-0.851). LM increased from baseline to post-testing for all groups [Mean difference [MD(Post-Pre) ± Standard Error (SE) = 0.78 ± 0.12 kg; p < 0.001]. While not significant (p = 0.081), SUP gained more LM compared to PL [MD(SUP-PL) ± SE = 3.5 ± 3.3 kg] and CON [MD(SUP-CON) ± SE = 5.2 ± 3.8 kg]. LM increased over time for both males (0.84 ± 0.24 kg; p = 0.003) and females (0.73 ± 0.14 kg; p < 0.001). The SUP group resulted in a significant increase in 1RM leg press compared to the CON group (89.9 ± 30.8 kg; p = 0.015), with no significant differences compared to PL (p = 0.409). The SUP group had greater increases in 1RM bench press compared to the CON group (9.8 ± 1.8 kg; p < 0.001), with no significant differences compared to PL (p = 0.99). Both sexes increased upper- (5.5 ± 0.7 kg; p < 0.001) and lower-body strength (69.8 ± 4.5 kg p < 0.001) with training. Conclusion: Nutrient supplementation timing appears to augment body composition changes and strength compared to control. Pre-/post-nutrient timing may support greater increases in LM and lower- and upper-body strength in both men and women. Clinical trial registration: [https://clinicaltrials.gov/ct2/show/NCT04230824?cond=NCT04230824&draw=2&rank=1], identifier [NCT04230824].

Differences in strength, leg lean mass, and lifestyle factors between premenopausal and perimenopausal women.

BACKGROUND: Menopausal changes coupled with age-related reductions in muscle strength can impact functionality. AIM: To evaluate the differences in muscle strength, dominant leg lean mass (DLMleg ), relative protein intake (r_PRO) and physical activity (PA) between premenopausal (PRE) and perimenopausal (PERI) women. METHODS: Twenty-four PRE- (age = 39.8 ± 3.3 years; BMI: 25.3 ± 5.0 kg/m2 ) and 24 PERI-women (age = 50.0 ± 3.3 years; BMI: 26.5 ± 5.4 kg/m2 ) participated in leg extensor isometric peak force (PF), DLMleg , r_PRO and PA. Independent samples t-tests and one-way analyses of covariance covaried for age and DLMleg were used to compare groups. RESULTS: The PRE group had significantly higher PF (mean difference ± standard error: 57.8 ± 28.0 N; p = 0.045) and DLMleg (0.7 ± 0.3 kg; p = 0.031) when compared to the PERI group. There were no significant differences in r_PRO, or PA between groups (p = 0.173-0.423). When covaried for age and DLMleg , there was no significant difference in PF (p = 0.982 and 0.405, respectively). CONCLUSIONS: Age and DLMleg may be important contributors to menopause-phase related differences in strength.

Body composition of NCAA division I football players pre- and post-COVID-19 stay-at-home advisory.

BACKGROUND: The COVID-19 pandemic forced collegiate athletes to train at home, without access to facilities. The purpose of this study was to evaluate the effect of the COVID-19 stay-at-home order on body composition of Division I Football Players, with a secondary aim to evaluate these changes between players with "higher" (>25 kg/m2) and "lower" (<25 kg/m2) Fat-Free Mass Index (kg/m2). METHODS: Body composition of 29 NCAA Division I Football Players (age=21.0±10 yr, Ht=186.7±5.6 cm, body mass=110.5±22.8 kg) were measured spring season (February) and prior to preseason (June). Whole body dual-energy X-ray absorptiometry scans were used to determine regional (arms, legs, trunk) and total body fat mass (FM), lean mass (LM), and fat-free mass (FFM). Fat-Free Mass Index (FFMI) was calculated as (LM+bone mineral content [BMC])/height2); participants were stratified by FFMI higher (N.=16) and lower (N.=13). RESULTS: Total LM (mean difference±standard error: 0.80±1.65 kg, P=0.016) increased from pre- to post-COVID stay-at-home. No significant changes in total FM were seen. Players with lower FFMI showed a significant decrease in trunk FM (-0.55±0.19 kg, P=0.016). Players with higher FFMI showed a significant increase in total LM (0.96±0.42 kg, P=0.038). CONCLUSIONS: These results suggest no detrimental effect on body composition.

Metabolic effects of menopause: a cross-sectional characterization of body composition and exercise metabolism.

OBJECTIVES: To evaluate body composition, fat distribution, and metabolism at rest and during exercise in premenopausal, perimenopausal, and postmenopausal women. METHODS: This cross-sectional study in 72 women ages 35 to 60 years evaluated body composition via a fourcompartment model, fat distribution using dual-energy x-ray absorptiometry-derived android to gynoid ratio, metabolic measures via indirect calorimetry, and lifestyle factors using surveys. One-way analyses of variance and one-way analyses of covariance covaried for age and hormone levels (estrogen and progesterone) were used to compare groups. RESULTS: Body fat percent was significantly lower in premenopausal than perimenopausal women (mean difference ± standard error: - 10.29 ± 2.73%, P = 0.026) despite similarities in fat mass and fat-free mass between groups (P≥0.217). Android to gynoid ratio was significantly lower in premenopausal than perimenopausal women (MD ± SE: -0.16 ± 0.05 a.u., P = 0.031). Resting energy expenditure was similar between groups (P = 0.999). Fat oxidation during moderate intensity cycle ergometer exercise was significantly greater in premenopausal than postmenopausal women (MD ± SE: 0.09 ± 0.03 g/min, P = 0.045). The change in respiratory exchange ratio between rest and moderate intensity exercise was significantly lower in premenopausal women than peri- (MD ± SE: -0.05 ± 0.03 a.u., P = 0.035) and postmenopausal women (MD ± SE: -0.06 ± 0.03 a.u., P = 0.040). Premenopausal women reported significantly fewer menopause symptoms than peri- (MD ± SE: -6.58 ± 1.52 symptoms, P = 0.002) and postmenopausal participants (MD ± SE: -4.63 ± 1.52 symptoms, P = 0.044), while similarities between groups were observed for lifestyle factors including diet and physical activity (P>0.999). CONCLUSIONS: Perimenopause may be the most opportune window for lifestyle intervention, as this group experienced the onset of unfavorable body composition and metabolic characteristics. VIDEO SUMMARY: http://links.lww.com/MENO/A932.