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1.
Eur J Appl Physiol ; 124(4): 1097-1107, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37847288

RESUMO

PURPOSE: Hemp contains protein with high concentrations of the branched-chain amino acids leucine, isoleucine, and valine and oils that have anti-inflammatory properties. Our purpose was to investigate the effects of hemp supplementation during resistance training in trained young adults. METHODS: Males (n = 22, 29 ± 8y) and females (n = 12, 30 ± 9y) were randomized (double-blind) to receive 60 g/d of hemp (containing 40 g protein and 9 g oil) or 60 g/d of soy (matched for protein and calories) during eight weeks of resistance training (~  4x/week). Before and after the intervention, participants were assessed for whole-body lean tissue and fat mass (dual-energy X-ray absorptiometry), regional muscle hypertrophy (ultrasound), strength (1-repetition maximum leg press, bench press, biceps curl), voluntary activation (interpolated twitch technique), resting twitch properties (single pulse; 0.5 ms) (before and after a fatigue test), markers of inflammation (Interleukin 6 and C-reactive protein), and bone resorption (urinary N-telopeptides). RESULTS: Hemp supplementation increased elbow flexor muscle thickness in females (2.6 ± 0.4-3.1 ± 0.5 cm, p = 0.012) while soy supplementation increased elbow flexor muscle thickness in males (3.7 ± 0.4-4.0 ± 0.5 cm, p < 0.01). Twitch torque and rate of torque development were preserved after a fatigue test in males consuming hemp compared to males on soy (p < 0.001). CONCLUSION: Overall, hemp provides some sex-specific beneficial effects on measures of muscle accretion and torque under fatiguing conditions in resistance trained young adults. CLINICALTRIALS: gov Identifier: NCT02529917, registered August 11, 2015.


Assuntos
Cannabis , Doenças Musculares , Treinamento Resistido , Feminino , Humanos , Masculino , Adulto Jovem , Composição Corporal , Suplementos Nutricionais , Método Duplo-Cego , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Adulto
2.
J Strength Cond Res ; 38(7): 1206-1212, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38595310

RESUMO

ABSTRACT: Hickmott, LM, Butcher, SJ, and Chilibeck, PD. A comparison of subjective estimations and objective velocities at quantifying proximity to failure for the bench press in resistance-trained men and women. J Strength Cond Res 38(7): 1206-1212, 2024-The purpose of this study was to compare the accuracy of quantifying repetitions in reserve (RIR) in the bench press among 18 men and 18 women between 2 conditions: (a) subjective estimations and (b) objective velocities. Subjects performed 4 sessions over 10 days: (a) 1 repetition maximum (1RM) test; (b) repetition-to-failure test at 80% of 1RM; (c) 3 sets to failure at 80% of 1RM; and (d) 3 sets to failure at 75, 80, and 85% of 1RM. During sessions 2, 3, and 4, subjects verbally stated their perceived 4 and 2 RIR intraset, whereas average concentric velocity was recorded on all repetitions. The dependent variable for the subjective estimations condition was the difference between the actual number of RIR and the subject's subjective estimated number of RIR at the verbally stated 4 and 2 RIR. The dependent variable for the objective velocities condition was the difference between the actual number of RIR and the number of RIR calculated from the subject's baseline individualized last repetition average concentric velocity-RIR profile. Significance was set at p ≤ 0.05. Sessions 3 and 4 had significant ( p < 0.001) condition × set and condition × load interactions, respectively, at both 4 and 2 RIR. Objective velocities were significantly more accurate than subjective estimations on set 1 and set 2 at both RIRs during session 3 and for 75 and 80% of 1RM at both RIRs during session 4. Objective velocities exhibit significantly greater accuracy than subjective estimations at quantifying RIR during initial sets and lower loads.


Assuntos
Treinamento Resistido , Levantamento de Peso , Humanos , Masculino , Treinamento Resistido/métodos , Feminino , Adulto Jovem , Adulto , Levantamento de Peso/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/fisiologia
3.
BMC Geriatr ; 23(1): 833, 2023 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-38082248

RESUMO

BACKGROUND: Process evaluations of randomized controlled trials (RCTs) of community exercise programs are important to help explain the results of a trial and provide evidence of the feasibility for community implementation. The objectives of this process evaluation for a multi-centre RCT of outdoor walking interventions for older adults with difficulty walking outdoors, were to determine: 1) implementation fidelity (the extent to which elements of the intervention were delivered as specified in the original protocol) and 2) participant engagement (the receipt of intervention components by the participants) in the Getting Older Adults Outdoors (GO-OUT) trial. METHODS: GO-OUT participants attended an active 1-day workshop designed to foster safe, outdoor walking skills. After the workshop, 190 people at 4 sites were randomized to an outdoor walk group (OWG) (n = 98) which met 2x/week for 10 weeks, or the weekly reminders (WR) group (n = 92) which received a phone reminder 1x/week for 10 weeks. The OWG had 5 components - warm-up, continuous distance walk, task-oriented walking activities, 2nd continuous distance walk, and cool-down. Data on implementation fidelity and participant engagement were gathered during the study through site communications, use of standardized forms, reflective notes of the OWG leaders, and accelerometry and GPS assessment of participants during 2 weeks of the OWG. RESULTS: All sites implemented the workshop according to the protocol. Participants were engaged in all 8 activity stations of the workshop. WR were provided to 96% of the participants in the WR intervention group. The 5 components of the OWG sessions were implemented in over 95% of the sessions, as outlined in the protocol. Average attendance in the OWG was not high - 15% of participants did not attend any sessions and 64% of participants in the OWG attended > 50% of the sessions. Evaluations with accelerometry and GPS during week 3 and 9 OWG sessions suggest that participants who attended were engaged and active during the OWG. CONCLUSIONS: This process evaluation helps explain the main study findings and demonstrates the flexibility required in the protocol for safe and feasible community implementation. Future research could explore the use of additional behaviour change strategies to optimize attendance for community implementation. TRIAL REGISTRATION: ClinicalTrials.gov NCT03292510 Date of registration: September 25, 2017.


Assuntos
Limitação da Mobilidade , Caminhada , Idoso , Humanos , Exercício Físico , Terapia por Exercício/métodos
4.
Nutr Health ; : 2601060231181605, 2023 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-37291968

RESUMO

Background: Iron deficiency (ID) is the most prevalent micronutrient deficiency in the world and the leading cause of anemia globally. Female athletes are at a disproportionate risk for ID due to blood loss through menstruation and decreased iron absorption secondary to exercise. Field peas are a rich source of iron but, similar to iron from other plant-based sources, the iron has limited bioavailability due to high levels of phytic acid, an inherent compound that binds to cations, creating a salt (phytate), which limits absorption during digestion. Aim: The purpose of our research was to investigate the effect of a field pea variety bred to have low levels of phytic acid on plasma ferritin, exercise performance, and body composition in female runners. Methods: Twenty-eight female runners (age:34.6 ± 9.7 years; weight: 65.1 ± 8.1 kg; VO2max: 50.7 ± 8.9 ml/kg/min) underwent measures of ferritin, exercise performance, and body composition before and after being randomly assigned to consume a powder derived from regular peas, low phytic acid peas, or a non-pea control (maltodextrin), plus vitamin C for 8 weeks. Results: The regular pea and low phytic acid pea groups had a 14.4% and 5.1% increase in plasma ferritin, respectively, while the maltodextrin group had a decrease of 2.2%; however, the difference in changes between groups was not statistically significant. No differences between groups were evident in any of the other measures. Conclusion: Larger doses or longer duration of pea supplementation may be necessary to induce meaningful changes in iron status. This trial was registered at ClinicalTrials.gov (NCT04872140).

5.
Eur J Appl Physiol ; 122(5): 1163-1178, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35150294

RESUMO

Individuals may opt to follow a plant-based diet for a variety of reasons, such as religious practices, health benefits or concerns for animal or environmental welfare. Such diets offer a broad spectrum of health benefits including aiding in the prevention and management of chronic diseases. In addition to health benefits, a plant-based diet may provide performance-enhancing effects for various types of exercise due to high carbohydrate levels and the high concentration of antioxidants and phytochemicals found in a plant-based diet. However, some plant-based foods also contain anti-nutrional factors, such as phytate and tannins, which decrease the bioavailability of key nutrients, such as iron, zinc, and protein. Thus, plant-based diets must be carefully planned to ensure adequate intake and absorption of energy and all essential nutrients. The current narrative review summarizes the current state of the research concerning the implications of a plant-based diet for health and exercise performance. It also outlines strategies to enhance the bioavailability of nutrients, sources of hard-to-get nutrients, and sport supplements that could interest plant-based athletes.


Assuntos
Dieta Vegetariana , Esportes , Atletas , Dieta , Exercício Físico , Humanos
6.
Nutr Health ; 28(4): 669-675, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33759633

RESUMO

Background: The number of Masters-level athletes (≥ 35 years of age) taking part in cycling has increased in the past years which may have beneficial effects on their health. The restrictions brought on by the COVID-19 pandemic has the potential to negatively impact the diet, training and fitness of these individuals due to restrictions in place to slow the spread of the virus. Aim: To investigate how the COVID-19 pandemic impacted the diet, training and fitness of Masters-level cyclists. Methods: 32 Masters cyclists (12 males, 20 females; mean age 47 ± 10 years) completed two incremental exercise tests one month apart during the pandemic to assess sport-specific fitness. Participants also completed online questionnaires to report their sedentary behavior and dietary intake before and during the pandemic, and their training volume and intensity for a specified week in February (before the pandemic) and each of March, April and May (during the pandemic). Results: No differences were seen in fitness (p = 0.6), training volume (p = 0.24) or intensity (p = 0.79) and sedentary behavior (p = 0.14) during the pandemic. Energy intake was unchanged (p = 1.0) during the pandemic, but participants consumed lower amounts of key nutrients such as fiber, vitamin A, omega-3 fatty acids and potassium (p < 0.05) while consuming more alcohol (p = 0.008) and vitamin C (p = 0.03). Conclusions: Our data shows that the COVID-19 pandemic has undesirable effects on nutrient and alcohol intake of Masters cyclists without impacting their training regimes, which may have adverse effects on their overall health and fitness in the long term.


Assuntos
COVID-19 , Pandemias , Masculino , Feminino , Humanos , Adulto , Pessoa de Meia-Idade , COVID-19/epidemiologia , Dieta , Ciclismo , Hábitos
7.
J Strength Cond Res ; 36(1): 259-261, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34743147

RESUMO

ABSTRACT: Downey, RJ, Deprez, DA, and Chilibeck, PD. Effects of postactivation potentiation on maximal vertical jump performance after a conditioning contraction in upper-body and lower-body muscle groups. J Strength Cond Res 36(1): 259-261, 2022-Postactivation potentiation (PAP) involves preperformance contractions that can condition a muscle to enhance subsequent force generation and power output. Our purpose was to examine the effects of conditioning contractions that are specific or nonspecific to the target performance on PAP. Resistance-trained subjects (14 males and 10 females) performed a 7-second isometric contraction involving back squat, bench press (as conditioning contractions), or a control condition (rest) on different days in random order, before maximal vertical jump performance. The back squat as a conditioning contraction increased maximal vertical jump by 1.1 ± 3.0 cm (p < 0.05); however, the bench press as a conditioning contraction unexpectedly reduced maximal vertical jump performance by 1.4 ± 2.7 cm (p < 0.05). Conditioning contractions used to elicit a PAP response should use muscles that are specific to the performance movement. Contractions that are not biomechanically similar to the performance movement may hinder subsequent performance.


Assuntos
Desempenho Atlético , Força Muscular , Humanos , Contração Isométrica , Masculino , Movimento , Contração Muscular , Músculo Esquelético , Descanso
8.
J Aging Phys Act ; 29(5): 886-899, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-33571958

RESUMO

Walking is a common activity among older adults. However, the effects of walking on health-related outcomes in people with low bone mineral density (BMD) are unknown. The authors included randomized controlled trials comparing walking to control in individuals aged ≥50 years with low BMD and at risk of fractures. The authors identified 13 randomized controlled trials: nine multicomponent interventions including walking, one that was walking only, and three Nordic walking trials. Most studies had a high risk of bias. Nordic walking may improve the Timed Up-and-Go values (1.39 s, 95% CI [1.00, 1.78], very low certainty). Multicomponent interventions including walking improved the 6-min walk test (39.37 m, 95% CI [21.83, 56.91], very low certainty) and lumbar spine BMD (0.01 g/cm2, 95% CI [0.00, 0.03], low certainty evidence). The effects on quality of life or femoral neck BMD were not significant. There were insufficient data on fractures, falls, or mortality. Nordic walking may improve physical functioning. The effects on other outcomes are less certain; one may need to combine walking with other exercises to be of benefit.


Assuntos
Fraturas Ósseas , Qualidade de Vida , Idoso , Terapia por Exercício , Humanos , Caminhada Nórdica , Caminhada
9.
Nutr Health ; 27(2): 151-159, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33234019

RESUMO

BACKGROUND: The combination of creatine supplementation and resistance training (10-12 weeks) has been shown to increase bone mineral content and reduce a urinary indicator of bone resorption in older males compared with placebo. However, the longer-term effects (12 months) of creatine and resistance training on bone mineral density and bone geometric properties in older males is unknown. AIM: To assess the effects of 12 months of creatine supplementation and supervised, whole-body resistance training on bone mineral density, bone geometric properties, muscle accretion, and strength in older males. METHODS: Participants were randomized to supplement with creatine (n = 18, 49-69 years, 0.1 g·kg-1·d-1) or placebo (n = 20, 49-67 years, 0.1 g·kg-1·d-1) during 12 months of supervised, whole-body resistance training. RESULTS: After 12 months of training, both groups experienced similar changes in bone mineral density and geometry, bone speed of sound, lean tissue and fat mass, muscle thickness, and muscle strength. There was a trend (p = 0.061) for creatine to increase the section modulus of the narrow part of the femoral neck, an indicator of bone bending strength, compared with placebo. Adverse events did not differ between creatine and placebo. CONCLUSIONS: Twelve months of creatine supplementation and supervised, whole-body resistance training had no greater effect on measures of bone, muscle, or strength in older males compared with placebo.


Assuntos
Creatina , Treinamento Resistido , Idoso , Composição Corporal , Suplementos Nutricionais , Método Duplo-Cego , Humanos , Masculino , Força Muscular , Músculo Esquelético , Músculos
10.
Clin Endocrinol (Oxf) ; 92(6): 525-535, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32092167

RESUMO

OBJECTIVE: Effects of lifestyle modification on reproductive function in polycystic ovary syndrome (PCOS) remain poorly elucidated. We compared the effects of a pulse-based diet (lentils, beans, split peas and chickpeas) with Therapeutic Lifestyle Changes (TLC) diet on ultrasonographic markers of ovarian morphology, hyperandrogenism and menstrual irregularity in PCOS. DESIGN: Randomized controlled trial. PATIENTS: Women with PCOS (18-35 years). MEASUREMENTS: Thirty women randomized to the pulse-based and 31 to TLC groups completed a 16-week intervention without energy restriction. Groups performed aerobic exercise (minimum of 5 days/wk; 45 minutes/d) and received health counselling (monthly) and longitudinal follow-up. Follicle numbers per ovary (FNPO, 2-9 mm), ovarian volume (OV), free androgen index (FAI) and menstrual cycle length were measured pre- and postintervention. RESULTS: Follicle numbers per ovary (mean change ± SD, -10 ± 15), OV (-2.7 ± 4.8 mL), FAI (-3 ± 2) and menstrual cycle length (-13 ± 47 days) decreased over time in both groups (All: P < .01), without group-by-time interactions (All: P ≥ .13). Attrition rate was 33.7% and comparable between groups (P = .94). Adherence to diet intervention negatively correlated with changes in FNPO (r=-0.54), OV (r=-0.35) and FAI (r = -.29) in pooled groups (All: P ≤ .04). Groups maintained reduced OV, FNPO, FAI and menstrual cycles 6 months postintervention; however, decreased FNPO and FAI at 16 weeks tended to revert to baseline levels 12 months postintervention in both groups (All: P ≤ .05). CONCLUSIONS: Both interventions improved ovarian dysmorphology, hyperandrogenism and menstrual irregularity in PCOS, and no diet appeared to be superior at improving reproductive outcomes. Our observations highlight the importance of longitudinal surveillance for sustainable adherence to newly adopted healthy lifestyle behaviours and reproductive health in PCOS (ClinicalTrials.gov identifier, NCT01288638).


Assuntos
Hiperandrogenismo , Síndrome do Ovário Policístico , Feminino , Seguimentos , Humanos , Estilo de Vida , Síndrome do Ovário Policístico/terapia
11.
J Am Coll Nutr ; 39(7): 657-664, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31986108

RESUMO

Objective: Tart cherry concentrate has been shown to improve muscle function, and reduce muscle damage, oxidative stress/inflammation, and muscle soreness in athletes; however, evidence for acute endurance performance benefits is scarce. The purpose of this review was to evaluate the effect of tart cherry juice on endurance exercise performance with a meta-analysis.Method: Data sources included Medline, Embase, Web of Science, and Google Scholar. Eligibility criteria were randomized controlled trials with endurance exercise performance tests. Participants were healthy individuals. Interventions included tart cherry supplementation and placebo ingested before, and/or on the day of exercise. Ten studies were included (totaling 127 males and 20 females). Standardized mean differences (SMD) with 95% confidence intervals were calculated for each study and pooled effects were assessed.Results: Tart cherry concentrate in juice or powdered form, ingested for 7 days to 1.5 hours before exercise performance testing significantly improved endurance exercise performance (SMD: 0.36; 95% CI: 0.07 to 0.64; p = 0.01; I2 = 0%) upon pooling of the ten studies.Conclusions: Tart cherry concentrate has a significant benefit for endurance exercise performance. Key teaching pointsTart cherry concentrate has a significant benefit for endurance exercise performance.Tart cherry concentrate may enhance endurance exercise performance via its low glycemic index, anti-inflammatory and anti-oxidative capacity, and blood flow enhancing effects.


Assuntos
Prunus avium , Frutas , Sucos de Frutas e Vegetais , Humanos , Mialgia , Estresse Oxidativo
12.
Curr Osteoporos Rep ; 18(4): 350-356, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32500480

RESUMO

PURPOSE OF REVIEW: The age-related loss of skeletal muscle and bone tissue decreases functionality and increases the risk for falls and injuries. One contributing factor of muscle and bone loss over time is chronic low-grade inflammation. Exercise training is an effective countermeasure for decreasing the loss of muscle and bone tissue, possibly by enhancing immune system response. Herein, we discuss key interactions between the immune system, muscle, and bone in relation to exercise perturbations, and we identify that there is substantial "cross-talk" between muscle and bone and the immune system in response to exercise. RECENT FINDINGS: Recent advances in our understanding of the "cross-talk" between muscle and bone and the immune system indicate that exercise is likely to mediate many of the beneficial effects on muscle and bone via their interactions with the immune system. The age-related loss of muscle and bone tissue may be partially explained by an impaired immune system via chronic low-grade inflammation. Exercise training has a beneficial effect on immune system function and aging muscle and bone. Theoretically, the "cross-talk" between the immune system, muscle, and bone in response to exercise enhances aging musculoskeletal health.


Assuntos
Envelhecimento/imunologia , Osso e Ossos/imunologia , Citocinas/imunologia , Exercício Físico/fisiologia , Sistema Imunitário/imunologia , Músculo Esquelético/imunologia , Humanos , Macrófagos/imunologia , Células Satélites de Músculo Esquelético/imunologia
13.
Int J Sport Nutr Exerc Metab ; 30(6): 420-426, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32916656

RESUMO

Dark chocolate (DC) is high in flavonoids and has been shown to increase nitric oxide in the blood. Increased nitric oxide has the potential to improve delivery of oxygen to muscle, especially in hypoxic conditions, such as altitude. Our aim was to assess the impact of DC supplementation on cycling performance at altitude. Twelve healthy, trained cyclists (n = 2 females, n = 10 males; age = 35 [12] years; height = 177 [7] cm; mass = 75.2 [11.0] kg; VO2max = 55 [6] ml·kg-1·min-1) were randomized to supplement with 60 g of DC or placebo twice per day for 14 days in a double-blind crossover study. After the 2 weeks of supplementation, the participants attended a laboratory session in which they consumed 120 g of DC or placebo and then cycled for 90 min at 50% peak power output, followed immediately by a 10-km time trial (TT) at simulated altitude (15% O2). The plasma concentration of blood glucose and lactate were measured before and at 15, 30, 60, and 90 min during the steady-state exercise and post TT, while muscular and prefrontal cortex oxygenation was measured continuously throughout exercise using near-infrared spectroscopy. DC resulted in a higher concentration of blood glucose (5.5 [0.5] vs. 5.3 [0.9] mmol/L) throughout the trial and lower blood lactate concentration following the TT (7.7 [1.92] vs. 10.0 [4.6] mmol/L) compared with the placebo. DC had no effect on the TT performance (19.04 [2.16] vs. 19.21 ± 1.96 min) or oxygenation status in either the prefrontal cortex or muscle. The authors conclude that, although it provided some metabolic benefit, DC is not effective as an ergogenic aid during TT cycling at simulated altitude.

14.
J Strength Cond Res ; 34(7): 1851-1859, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32358310

RESUMO

Schwanbeck, SR, Cornish, SM, Barss, T, and Chilibeck, PD. Effects of training with free weights versus machines on muscle mass, strength, free testosterone, and free cortisol levels. J Strength Cond Res 34(7): 1851-1859, 2020-Free weights offer a more unstable training environment, which enhances muscle recruitment, whereas some machines have the advantage of using a "cam" pulley system that better matches strength curves. We compared the effect of training with free weights vs. machines on muscle mass, strength, free testosterone, and free cortisol concentrations. Forty-six subjects (26 women; 22 ± 3 years) were randomized to train using free weights or machines for 8 weeks (with each muscle group trained 2-3/weeks, 3-4 sets of 4-10 repetitions). Muscle thickness and strength were measured at 0 and 8 weeks. Salivary hormone concentrations were assessed before and at the end of workouts at the beginning, midway (4 weeks), and end (8 weeks) of the training intervention. Biceps and quadriceps muscle thickness increased (p < 0.01) with no difference between groups. There was a group × time interaction for machine bench press strength (p = 0.05) with the machine group increasing more than the free-weight group (13.9 vs. 8.6%). Free-weight bench press and squat, and Smith machine squat strength increased in both groups (11-19%; p < 0.01) with no difference between groups. Men in the free-weight group had a greater increase in free testosterone from before to after acute training sessions than men in the machine group and all women (p < 0.01); however, there was no differences between groups in free cortisol response to acute resistance exercise. Training sessions with free weights induced greater increases in free testosterone in men; however, training with free weights or machines resulted in similar increases in muscle mass and strength.


Assuntos
Músculo Quadríceps/anatomia & histologia , Músculo Quadríceps/fisiologia , Treinamento Resistido/métodos , Adulto , Braço , Exercício Físico/fisiologia , Feminino , Humanos , Hidrocortisona/metabolismo , Masculino , Força Muscular , Distribuição Aleatória , Treinamento Resistido/instrumentação , Saliva/metabolismo , Testosterona/metabolismo , Adulto Jovem
15.
J Strength Cond Res ; 34(9): 2482-2491, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32865944

RESUMO

Whinton, AK, Donahoe, K, Gao, R, Thompson, KMA, Aubry, R, Saunders, TJ, Johnston, A, Chilibeck, PD, and Burr, JF. Repeated application of a novel creatine cream improves muscular peak and average power in male subjects. J Strength Cond Res 34(9): 2482-2491, 2020-Using a multicenter, randomized controlled trial, (N = 123, age 23 ± 4 years) we sought to determine whether administration of a novel, topical creatine supplement could improve muscular performance after acute and repeated (7-day) exposure. To study the acute performance enhancing effects of the supplement, subjects completed 5 sets of 15 maximal concentric single-leg knee extensions with and without the application of a low- (low dose [LD]-3.5 ml) or high-dose (high dose [HD]-7 ml) topical creatine cream. After a wash-out period, subjects had one leg randomized to receive either the creatine or placebo cream, with further randomization into an oral creatine or placebo supplement group. Subjects completed 5 sets of 15 maximal concentric single leg knee extensions before and after the supplementation protocol. After acute application, no significant differences in peak power (LD: 252 ± 93 W, HD: 261 ± 100 W, p = 0.21), average power (LD: 172 ± 65 W, HD: 177 ± 69 W, p = 0.78), or fatigue index (LD: 13.4 ± 10.6%, HD: 14 ± 11.9%, p = 0.79) were observed between experimental and placebo creams (peak power: LD: 244 ± 76 W, HD: 267 ± 109 W; average power: LD: 168 ± 57 W, HD: 177 ± 67 W; fatigue index: LD: 12.4 ± 9.6%, HD: 12.8 ± 10.6%) or when controlling for sex. After the 7-day supplementation protocol, a significant increase in average power (creatine: 203 ± 61-220 ± 65 W, placebo: 224 ± 61-214 ± 61 W) and peak power (creatine: 264 ± 73-281 ± 80 W, placebo: 286 ± 79-271 ± 73 W) in the leg receiving creatine cream was observed in male subjects. No differences were observed in female subjects. The topical creatine cream did not enhance measures of muscle performance after acute application, but was able to improve peak and average power in male subjects after 7 consecutive days of application.


Assuntos
Creatina/administração & dosagem , Força Muscular/efeitos dos fármacos , Pomadas , Adolescente , Adulto , Relação Dose-Resposta a Droga , Método Duplo-Cego , Teste de Esforço , Humanos , Masculino , Adulto Jovem
16.
BMC Endocr Disord ; 19(1): 70, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31262307

RESUMO

BACKGROUND: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in young women and increases risk of cardiovascular and metabolic disease, and infertility. Women with PCOS share many characteristics commonly associated with aging including chronic inflammation and insulin resistance, which may be associated with "sarcopenic obesity", a term used to describe low appendicular skeletal muscle mass relative to total body mass. The purpose of this work was to determine the prevalence of sarcopenic obesity in women with PCOS. We hypothesized there would be a high prevalence of sarcopenic obesity, and that % appendicular skeletal muscle mass and markers of inflammation and insulin resistance would be inversely correlated in this population. METHODS: Dual energy X-ray absorptiometry was used to assess body composition in 68 women with PCOS aged 18-35y and 60 healthy age-matched women from the same geographic area. Sarcopenic obesity was defined as having % appendicular skeletal muscle mass 2 standard deviations below the mean for the healthy age-matched controls and a % body fat above 35%. Data were analyzed with Mann-Whitney U-tests and Spearman correlations. RESULTS: 53% of women with PCOS were classified as sarcopenic obese. Women with PCOS had a median (interquartile range) appendicular skeletal muscle mass of 23.8 (22.3-25.8)% which was lower than the control median of 30.4 (28.6-32.4)% (p < 0.0001). Among women with PCOS, there were negative correlations between % appendicular skeletal muscle mass and the homeostasis model assessment insulin resistance index (r = - 0.409; p < 0.01), high sensitivity C-reactive protein (r = - 0.608; p < 0.0001) and glycosylated hemoglobin (r = - 0.430; p < 0.0001). Furthermore, % appendicular skeletal muscle mass correlated positively with vitamin D (r = 0.398; p < 0.0001) in women with PCOS, which is thought to positively affect skeletal muscle mass. CONCLUSIONS: Women with PCOS have a high prevalence of sarcopenic obesity, which is correlated to insulin resistance and inflammation.


Assuntos
Composição Corporal , Obesidade/complicações , Síndrome do Ovário Policístico/complicações , Sarcopenia/complicações , Absorciometria de Fóton , Índice de Massa Corporal , Estudos de Casos e Controles , Feminino , Humanos , Insulina/metabolismo , Resistência à Insulina , Obesidade/epidemiologia , Fatores de Risco , Sarcopenia/epidemiologia , Vitamina D/sangue
17.
J Obstet Gynaecol Can ; 41(10): 1453-1460, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30712903

RESUMO

OBJECTIVE: This study compared the prevalence of metabolic syndrome (MetS) and characterized type 2 diabetes (DM2) and cardiovascular disease (CVD) risk profiles between Canadian women with polycystic ovary syndrome (PCOS) and healthy women recruited from the general population. Furthermore, within the PCOS cohort, the study contrasted the CVD and DM2 risk profiles of women with or without MetS. METHODS: Measures of MetS (International Diabetes Federation; National Heart, Lung, and Blood Institute; and the American Heart Association definition), DM2 (Diabetes Canada Clinical Guidelines), and CVD risk factors (Androgen Excess and Polycystic Ovary Syndrome Society statement) were evaluated for 237 women with PCOS (Androgen Excess and PCOS Society definitions) and 42 controls (aged 18-36) in a prospective observational study (Canadian Task Force Classification II-2). RESULTS: The prevalence of MetS was 29.5% in the PCOS group, which was approximately six-fold higher than age-matched controls (P < 0.001). Women with PCOS exhibited higher glucose abnormality, acanthosis nigricans, total cholesterol to high-density lipoprotein cholesterol ratio (TC/HDL-C), and lower sex hormone-binding globulin concentrations when compared with controls after accounting for differences in the BMI (P < 0.01). Further, women with PCOS and MetS exhibited exacerbated insulin and glucose responses to a 75-g oral glucose tolerance test and greater acanthosis nigricans, hirsutism, TC/HDL-C, TC, and sex hormone-binding globulin concentrations compared with their BMI-adjusted counterparts without MetS (P < 0.05). CONCLUSION: Canadian reproductive-age women with PCOS have a high prevalence of MetS and exhibit adverse cardiometabolic risk factors that warrant early screening and regular monitoring across their reproductive lifespan.


Assuntos
Doenças Cardiovasculares/epidemiologia , Diabetes Mellitus Tipo 2/epidemiologia , Intolerância à Glucose/epidemiologia , Síndrome Metabólica/epidemiologia , Síndrome do Ovário Policístico/epidemiologia , Acantose Nigricans/epidemiologia , Acne Vulgar/epidemiologia , Adolescente , Adulto , Glicemia/metabolismo , Pressão Sanguínea , Índice de Massa Corporal , Canadá/epidemiologia , Estudos de Casos e Controles , Colesterol/sangue , HDL-Colesterol/sangue , LDL-Colesterol , Feminino , Intolerância à Glucose/metabolismo , Teste de Tolerância a Glucose , Hirsutismo/epidemiologia , Humanos , Resistência à Insulina , Síndrome Metabólica/metabolismo , Síndrome do Ovário Policístico/metabolismo , Prevalência , Estudos Prospectivos , Medição de Risco , Globulina de Ligação a Hormônio Sexual/metabolismo , Adulto Jovem
18.
J Clin Densitom ; 21(1): 54-60, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28034591

RESUMO

Polycystic ovary syndrome (PCOS) is an endocrine disorder affecting women of reproductive age manifesting with polycystic ovaries, menstrual irregularities, hyperandrogenism, hirsutism, and insulin resistance. The oligomenorrhea and amenorrhea characteristic to PCOS are associated with low bone mineral density (BMD); conversely, the hyperandrogenism and hyperinsulinemia may elicit a protective effect on BMD. As bone geometric properties provide additional information about bone strength, the objective of this study was to compare measures of hip geometry in women with PCOS to a healthy female population. Using dual-energy X-ray absorptiometry, BMD and measures of hip geometry were determined in women with PCOS (n = 60) and healthy controls (n = 60) aged 18-35 years. Clinical biochemical measures were also determined in women with PCOS. Measures of hip geometry, including cross-sectional area, cross-sectional moment of inertia, subperiosteal width (SPW), and section modulus, were similar between groups following correction for body mass index (BMI) (all p > 0.05) with intertrochanter SPW significantly lower in women with PCOS (p < 0.05). BMI-corrected whole body BMD as well as the lumbar spine and regions of proximal femur were also comparable between groups. In women with PCOS, BMI-corrected correlations were found between insulin and femoral shaft SPW (r = 0.322, p < 0.05), glucose and femoral neck (r = 0.301, p < 0.05), and trochanter BMD (0.348, p < 0.05), as well as between testosterone and femoral neck BMD (0.376, p < 0.05) and narrow neck cross-sectional area (0.306, p < 0.05). This study demonstrates that women with PCOS may have compromised intertrochanter SPW while oligomenorrhea appears to have no detrimental effect on bone density or geometry in women with PCOS.


Assuntos
Densidade Óssea , Fêmur/diagnóstico por imagem , Síndrome do Ovário Policístico/diagnóstico por imagem , Síndrome do Ovário Policístico/fisiopatologia , Absorciometria de Fóton , Adolescente , Adulto , Glicemia/metabolismo , Índice de Massa Corporal , Estudos de Casos e Controles , Diáfises/diagnóstico por imagem , Diáfises/fisiopatologia , Feminino , Fêmur/fisiopatologia , Cabeça do Fêmur/diagnóstico por imagem , Cabeça do Fêmur/fisiopatologia , Colo do Fêmur/diagnóstico por imagem , Colo do Fêmur/fisiopatologia , Humanos , Insulina/sangue , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/fisiopatologia , Testosterona/sangue , Adulto Jovem
20.
Eur J Appl Physiol ; 123(7): 1411-1413, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37154950
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