Resistance Training In Young Adults Research Articles

Limited effect of over-the-counter doses of ibuprofen on mechanisms regulating muscle hypertrophy during resistance training in young adults.

We have previously shown that maximal over-the-counter doses of ibuprofen, compared with low doses of acetylsalicylic acid, reduce muscle hypertrophy in young individuals after 8 wk of resistance training. Because the mechanism behind this effect has not been fully elucidated, we here investigated skeletal muscle molecular responses and myofiber adaptations in response to acute and chronic resistance training with concomitant drug intake. Thirty-one young (aged 18-35 yr) healthy men (n = 17) and women (n = 14) were randomized to receive either ibuprofen (IBU; 1,200 mg daily; n = 15) or acetylsalicylic acid (ASA; 75 mg daily; n = 16) while undergoing 8 wk of knee extension training. Muscle biopsies from the vastus lateralis were obtained before, at week 4 after an acute exercise session, and after 8 wk of resistance training and analyzed for mRNA markers and mTOR signaling, as well as quantification of total RNA content (marker of ribosome biogenesis) and immunohistochemical analysis of muscle fiber size, satellite cell content, myonuclear accretion, and capillarization. There were only two treatment × time interaction in selected molecular markers after acute exercise (atrogin-1 and MuRF1 mRNA), but several exercise effects. Muscle fiber size, satellite cell and myonuclear accretion, and capillarization were not affected by chronic training or drug intake. RNA content increased comparably (∼14%) in both groups. Collectively, these data suggest that established acute and chronic hypertrophy regulators (including mTOR signaling, ribosome biogenesis, satellite cell content, myonuclear accretion, and angiogenesis) were not differentially affected between groups and therefore do not explain the deleterious effects of ibuprofen on muscle hypertrophy in young adults.NEW & NOTEWORTHY Here we show that mTOR signaling, fiber size, ribosome biogenesis, satellite cell content, myonuclear accretion, and angiogenesis were not differentially affected between groups undergoing 8 wk of resistance training with concomitant anti-inflammatory medication (ibuprofen versus low-dose aspirin). Atrogin-1 and MuRF-1 mRNA were more downregulated after acute exercise in the low-dose aspirin group than in the ibuprofen group. Taken together it appears that these established hypertrophy regulators do not explain the previously reported deleterious effects of high doses of ibuprofen on muscle hypertrophy in young adults.

Timing of creatine supplementation does not influence gains in unilateral muscle hypertrophy or strength from resistance training in young adults: a within-subject design

Creatine supplementation, in close proximity to resistance training sessions, may be an important strategy to augment muscle accretion and strength. The purpose of this study was to examine the effects of creatine supplementation immediately before compared to immediately after unilateral resistance training on hypertrophy and strength. Using a counter-balanced, double-blind, repeated measures within-subject design, ten recreationally active participants (7 males; 3 females; age: 23±5 years; height: 174±9 cm; body mass: 73.5±9.7 kg) were randomized to supplement with creatine monohydrate (0.1 g/kg of body mass) immediately before and placebo immediately after training one side of the body and placebo immediately before and creatine immediately after training the other side of the body on alternate days. Resistance training consisted of elbow flexion and knee extension (3-6 sets at 80% 1-repetition maximum [1-RM]) for 8 weeks. Prior to and following training, muscle thickness (elbow flexors and leg extensors; ultrasonography) and strength (1-RM for the elbow flexors and knee extensors) was assessed. There was a significant increase over time for muscle thickness, strength, and relative strength (P<0.01), with no differences between creatine ingestion strategies. Total training volume performed was similar between conditions (P=0.56). Creatine supplementation, immediately before or immediately after unilateral resistance training, produces similar gains in muscle hypertrophy and strength in young adults.

Fish Protein Ingestion Induces Neural, but Not Muscular Adaptations, Following Resistance Training in Young Adults.

Purpose: Nutritional supplementation in conjunction with exercise is of interest for the prevention or improvement of declines in motor performances in older adults. An understanding of the effects on both young and older adults contributes to its effective application. We investigated the effect of fish protein ingestion with resistance training on neural and muscular adaptations in young adults using interventions and assessments that have already been tested in older adults.Methods: Eighteen young adults underwent 8 weeks of isometric knee extension training. During the intervention, nine participants ingested 5 g of fish protein (n = 9, Alaska pollack protein, APP), and the other nine participants ingested casein as a control (n = 9, CAS) in addition to daily meals. Before, during, and after the intervention, the isometric knee extension force, lower extremity muscle mass, and motor unit firing pattern of knee extensor muscles were measured.Results: Maximum voluntary contraction (MVC) was significantly increased in both APP and CAS groups from 0 weeks to 4, 6, and 8 weeks of intervention (p < 0.001), but there were no significant differences between the groups (p = 0.546–0.931). Muscle mass was not significantly changed during the intervention in either group (p = 0.250–0.698). Significant changes in motor unit firing rates (p = 0.02 and 0.029 for motor units recruited at 20–40% of MVC and at 40–60%) were observed following the intervention in the APP but not CAS (p = 0.120–0.751) group.Conclusions: These results suggest that dietary fish protein ingestion changes motor unit adaptations following resistance training in young adults.

Reductions in Cardiopulmonary Disease Risk Following Calisthenic Concurrent Aerobic and Resistance Training in Young Adults in a Low Resource Setting

Background: Studies have demonstrated that young adults, especially in low- to middle-income countries, are increasingly susceptible to unfavorable alterations in body composition during their transition from adolescence to adulthood. This places young adults at an increased risk for numerous chronic diseases, such as cardiovascular, and/or pulmonary diseases. Objectives: This study aimed to determine if concurrent aerobic and resistance calisthenic training could reduce cardiopulmonary disease risk in young adults in a low resource setting. Methods: Thirty young adult males were randomly assigned to either a six-week non-exercising control group (NON) or concurrent aerobic or resistance training group (CON) that engaged in three, non-consecutive, 60-minute exercise sessions using a combination of 4 - 5 progressive resistance training exercises for two sets of 15 - 20 repetitions and 30 minutes of aerobic exercises at a rating of perceived exertion of 9 - 15. This study assessed anthropometry (body mass, stature, body mass index waist-to-hip ratio, waist-to-stature ratio, sum of skinfolds, percentage body fat, fat mass, fat free mass and conicity index) and lung function (forced vital capacity (FVC), forced expired volume in one second (FEV1), forced expiratory volume in one second/forced vital capacity ratio (FEV1/FVC), peak expiratory flow (PEF), maximal expiratory flow at 75% (MEF75%), maximal expiratory flow at 50% (MEF50%) and maximal expiratory flow at 25 (MEF25%). Results: Concurrent training resulted in significant (P ≤ 0.05) improvements in waist-to-hip ratio (0.94 ± 0.04 to 0.92 ± 0.05; P = 0.042), fat free mass (57.46 ± 9.16 to 58.21 ± 8.65 kg; P = 0.018), percentage body fat (14.56 ± 5.96 to 13.24 ± 5.77%, P = 0.006), fat mass (10.22 ± 5.31 to 9.29 ± 5.17 kg; P = 0.008), sum of skinfolds (96.22 ± 35.64 to 87.67 ± 32.15 mm; P = 0.004), PEF (5.06 ± 2.04 to 6.57 ± 2.51 L; P = 0.018), MEF75% (4.78 ± 2.01 to 6.24 ± 1.99 L.sec-1; P = 0.026), MEF50% (4.08 ± 1.20 to 5.24 ± 1.44 L.sec-1; P = 0.043) and MEF25% (2.66 ± 0.63 to 3.31 ± 1.87 L.sec-1; P = 0.038). Conclusions: The findings support the feasibility and efficacy of a simple and inexpensive concurrent aerobic and resistance training program to simultaneously improve body composition and lung function in an attempt to curb the increasing incidence of overweight/obesity and associated lung dysfunction in young adults in a low resource setting.

Improved Endothelial Function Following Eight Weeks Of Low-intensity Resistance Training In Young Adults

Cardiovascular diseases (CVD) are the leading cause of death worldwide, and compelling evidence indicates that exercise prevents and attenuates CVD. Resistance training (RT) exerts positive health effects; however, there is a lack of evidence regarding the RT intensities that could be prescribed to improve vascular endothelial function. PURPOSE: To compare the effects of two RT intensities during eight weeks on vascular endothelial function in sedentary young males. METHODS: Thirty-four sedentary men were recruited (age = 20.6 ± 1.8 yr., height = 171.3 ± 5.2 cm, weight = 65.2 ± 10.6 kg, DXA fat mass = 22.3 ± 7.4 %), and randomly assigned to a control group (CTRL, no exercise), RT at 50% of a maximum repetition [1-RM] and RT at 80% 1-RM. The RT program was performed twice a week for eight weeks, and except for the CTRL group, participants performed the same RT exercises at similar total workloads (1920 arbitrary units [AU] for the 80%RM and 1950 AU for the 50%RM). Vascular endothelial function was measured before (pre) and after (post) eight weeks by ultrasound and determined by the percentage of flow-mediated dilatation (%FMD). Mixed factorial ANOVA (3 groups x 2 measurements x 2 occlusions), effect size (ES) and 95% confidence interval (CI95%) were computed for %FMD. RESULTS: A significant triple interaction was found on %FMD (p = 0.021). The eight-week post-intervention follow-up analyses showed a significant increase (p = 0.010) in %FMD in the 50%RM (Mean = 9.93 ± 3.73%, ES = 3.70, CI95% = 1.59 to 5.79) compared to the control group (Mean = 5.72 ± 1.71%, ES = 1.67, CI95% = -0.21 to 3.55), and no significant differences between 50%RM and 80%RM (Mean = 7.90 ± 2.51%, ES = 2.18, CI95% = 0.27 to 4.10), and between 80%RM and control groups. CONCLUSION: A 50%RM intensity RT program elicited a positive vascular endothelial function adaptation following eight-weeks of training. It seems unnecessary to perform high-intensity RT to obtain arterial health benefits.

Trampoline Versus Resistance Training in Young Adults: Effects on Knee Muscles Strength and Balance

ABSTRACTPurpose: Trampoline parks are becoming popular in many countries, providing recreational facilities for children and adults. This study investigated the effects of trampoline training on knee muscles strength and balance in young adults. Methods: Twenty-six participants (14 males, 12 females) were randomized into trampoline training (TT) and resistance training (RT) groups to undergo a 6-week supervised intervention program (2 × 30 min per week). TT group performed basic trampoline exercises while the RT group performed resistance training targeting lower extremities muscles. Peak knee extension and flexion torque, postural sway characteristics, and Y balance test (YBT) performance were evaluated before and after the intervention. A mixed model analysis of variance (group × time) was applied. Results: After training there were significant improvements in knee extension torque (mean differencepost-pre [95% CI], TT: 0.27 [0.00, 0.54] N∙m/kg, RT: 0.31 [0.09,0.54] N∙m/kg, p = .001), knee flexion torque (TT: 0.25 [0.17,0.33] N∙m/kg, RT: 0.21 [0.08,0.34] N∙m/kg, p < .001), and dynamic balance (YBT composite scores, mean differencepost-pre [95% CI], TT: 4.9 [−0.3, 10.2]%, RT: 5.2 [2.4,8.0]%, p = .001). No difference between groups was found. Conclusion: Trampoline training can be as effective as resistance training for improving knee muscles strength and dynamic balance in young men and women.

High doses of anti-inflammatory drugs compromise muscle strength and hypertrophic adaptations to resistance training in young adults.

This study tested the hypothesis that high doses of anti-inflammatory drugs would attenuate the adaptive response to resistance training compared with low doses. Healthy men and women (aged 18-35years) were randomly assigned to daily consumption of ibuprofen (IBU; 1200mg; n=15) or acetylsalicylic acid (ASA; 75mg; n=16) for 8weeks. During this period, subjects completed supervised knee-extensor resistance training where one leg was subjected to training with maximal volitional effort in each repetition using a flywheel ergometer (FW), while the other leg performed conventional (work-matched across groups) weight-stack training (WS). Before and after training, muscle volume (MRI) and strength were assessed, and muscle biopsies were analysed for gene and protein expression of muscle growth regulators. The increase in m. quadriceps volume was similar between FW and WS, yet was (averaged across legs) greater in ASA (7.5%) compared with IBU (3.7%, group difference 34cm3 ; P=0.029). In the WS leg, muscle strength improved similarly (11-20%) across groups. In the FW leg, increases (10-23%) in muscle strength were evident in both groups yet they were generally greater (interaction effects P<0.05) for ASA compared with IBU. While our molecular analysis revealed several training effects, the only group interaction (P<0.0001) arose from a downregulated mRNA expression of IL-6 in IBU. Maximal over-the-counter doses of ibuprofen attenuate strength and muscle hypertrophic adaptations to 8weeks of resistance training in young adults. Thus, young individuals using resistance training to maximize muscle growth or strength should avoid excessive intake of anti-inflammatory drugs.

Association of Age with Muscle Size and Strength Before and After Short-Term Resistance Training in Young Adults

The purpose of this study was to assess the association of age with muscle mass and strength in a group of young adults before and after 12 weeks of progressive resistance training. Eight hundred twenty-six young males and females (age 24.34 +/- 5.69 yr, range 18-39 yr) completed a strictly supervised 12-week unilateral resistance training program of the nondominant arm. Isometric (maximal voluntary contraction [MVC]) and dynamic strength (1 repetition maximum [1RM]) of the elbow flexors and cross-sectional area (CSA) of the biceps-brachii using magnetic resonance imaging (MRI) scans were measured before and after training. Pearson correlation coefficients were calculated for size and strength variables and age. In addition, the cohort was divided into groups according to decade of life and differences assessed by analysis of variance. Age correlated significantly and positively with all pretraining measures of muscle size and strength (CSA: r = 0.191, p < 0.001; MVC: r = 0.109, p = 0.002; 1RM: r = 0.109, p = 0.002). Age was not related to the training-induced changes in CSA or MVC but was negatively associated with the change in 1RM (r = -0.217, p < 0.001). The study indicates that age does have a significant positive relationship with muscle size and strength in untrained young adults. Although age was negatively associated with improvements in 1RM, the effect of age was small relative to the improvements induced through resistance training, thus suggesting age does not limit response to training in any practical way during early adulthood.

Effect of Whey and Soy Protein Supplementation Combined with Resistance Training in Young Adults

The purpose was to compare changes in lean tissue mass, strength, and myofibrillar protein catabolism resulting from combining whey protein or soy protein with resistance training. Twenty-seven untrained healthy subjects (18 female, 9 male) age 18 to 35 y were randomly assigned (double blind) to supplement with whey protein (W; 1.2 g/kg body mass whey protein + 0.3 g/kg body mass sucrose power, N = 9: 6 female, 3 male), soy protein (S; 1.2 g/kg body mass soy protein + 0.3 g/kg body mass sucrose powder, N= 9: 6 female, 3 male) or placebo (P; 1.2 g/kg body mass maltodextrine + 0.3 g/kg body mass sucrose powder, N = 9: 6 female, 3 male) for 6 wk. Before and after training, measurements were taken for lean tissue mass (dual energy X-ray absorptiometry), strength (1-RM for bench press and hack squat), and an indicator of myofibrillar protein catabolism (urinary 3-methylhistidine). Results showed that protein supplementation during resistance training, independent of source, increased lean tissue mass and strength over isocaloric placebo and resistance training (P < 0.05). We conclude that young adults who supplement with protein during a structured resistance training program experience minimal beneficial effects in lean tissue mass and strength.

Effects of Physical Training and Detraining, Immobilisation, Growth and Aging on Human Fascicle Geometry

In addition to its size and the extent of its neural activation, a muscle's geometry (the angles and lengths of its fibres or fascicles) strongly influences its force production characteristics. As with many other tissues within the body, muscle displays significant plasticity in its geometry. This review summarises geometric differences between various athlete populations and describes research examining the plasticity of muscle geometry with physical training, immobilisation/detraining, growth and aging. Typically, heavy resistance training in young adults has been shown to cause significant increases in fascicle angle of vastus lateralis and triceps brachii as measured by ultrasonography, while high-speed/plyometrics training in the absence of weight training has been associated with increases in fascicle length and a reduction in angles of vastus lateralis fascicles. These changes indicate that differences in geometry between various athletic populations might be at least partly attributable to their differing training regimes. Despite some inter-muscular differences, detraining/unloading is associated with decreases in fascicle angle, although little change was shown in muscles such as vastus lateralis and triceps brachii in studies examining the effects of prolonged bed rest. No research has examined the effects of other interventions such as endurance or chronic stretching training. Few data exist describing geometric adaptation during growth and maturation, although increases in gastrocnemius fascicle angle and length seem to occur until maturation in late adolescence. Although some evidence suggests that a decrease in both fascicle angle and length accompanies the normal aging process, there is a paucity of data examining the issue; heavy weight training might attenuate the decline, at least in fascicle length. A significant research effort is required to more fully understand geometric adaptation in response to physical training, immobilisation/detraining, growth and aging.

Excess Adiposity Limits The Muscle Strength Response To Resistance Training

Evidence is limited but suggests that overweight and obesity may attenuate the muscle strength response to resistance training (RT). PURPOSE To investigate the influence of overweight and obesity on the muscle strength and size adaptations to a 12 wk unilateral, upper arm RT program in a large sample of apparently healthy, young adults. METHODS Subjects were 449 normal weight (NW) (mean ± SEM) (22.0 ± 0.1 kg/m2, 23.3 ± 0.2 yr) and 238 overweight to obese (OW) (29.2 ± 0.3 kg/m2, 25.6 ± 0.4 yr) men (n=285) and women (n=402) who had not performed RT for 1 yr prior to study participation. Subjects underwent 12 wks (2 d/wk) of supervised RT on the non-dominant arm. Peak elbow flexor muscle strength (kg) was evaluated by isometric testing and 1 repetition maximum (1RM). Biceps muscle cross sectional area (cm2) was measured by magnetic resonance imaging. Muscle strength data were analyzed with no correction (absolute), corrected for baseline strength values (relative), and scaled for body weight by the allometric method (allometric). Biceps cross sectional area was analyzed with no correction (absolute) and corrected for initial values (relative). Multivariate ANOVA was used to detect if muscle strength and size differed between NW and OW pre-RT, post-RT, and pre- to post-RT. RESULTS OW had greater pre-RT absolute elbow flexor peak isometric (50.4 ± 1.0 vs 42.2 ± 0.7 kg) and 1RM (10.1 ± 0.2 vs 8.3 ± 0.1 kg) strength and biceps size (19.5 ± 0.3 vs 16.4 ± 0.2 cm2) than NW (p <0.001). Similarly, OW had greater post-RT absolute elbow flexor peak isometric (58.1 ± 1.1 vs 50.6 ± 0.8 kg) and 1RM (14.2 ± 0.2 vs 12.4 ± 0.1 kg) strength and biceps size (23.1 ± 0.4 vs 19.6 ± 0.3 cm2) than NW (p <0.001). Absolute peak elbow flexor strength gains were similar between OW and NW pre- to post-RT. In contrast, NW had greater relative peak elbow flexor isometric (21.2 ± 1.0 vs 17.4 ± 1.4%) and 1RM (54.3 ± 1.5 vs 49.0 ± 2.0%) strength increases than OW pre- to post-RT (p <0.05). Further, NW had greater allometric peak elbow flexor isometric (0.48 ± 0.02 kg·kg−0.67 vs 0.40 ± 0.03 kg·kg−0.67) and 1 RM (0.25 ± 0.00 vs 0.22 ± 0.01 kg·kg−0.67) strength increases than OW pre- to post-RT (p <0.05). Absolute biceps size gains were greater in OW than NW (p <0.001); however, relative biceps size increases were similar between OW and NW (18.4 ± 0.7 vs 19.4 ± 0.5%) pre- to post-RT. CONCLUSION Despite similar relative increases in biceps size, NW had greater relative and allometric gains in peak elbow flexor strength than NW. Excess overall adiposity may limit the muscle strength response to RT in young adults. Supported by NIH-NINDS R01 NS40606-02