No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Cycle training induces muscle hypertrophy and strength gain: Strategies and mechanisms (review)
Abstract
Cycle training is widely performed as a major part of any exercise program seeking to improve aerobic capacity and cardiovascular health. However, the effect of cycle training on muscle size and strength gain still requires further insight, even though it is known that professional cyclists display larger muscle size compared to controls. Therefore, the purpose of this review is to discuss the effects of cycle training on muscle size and strength of the lower extremity and the possible mechanisms for increasing muscle size with cycle training. It is plausible that cycle training requires a longer period to significantly increase muscle size compared to typical resistance training due to a much slower hypertrophy rate. Cycle training induces muscle hypertrophy similarly between young and older age groups, while strength gain seems to favor older adults, which suggests that the probability for improving in muscle quality appears to be higher in older adults compared to young adults. For young adults, higher-intensity intermittent cycling may be required to achieve strength gains. It also appears that muscle hypertrophy induced by cycle training results from the positive changes in muscle protein net balance.
... In the secondary search, the reference lists of all included publications were screened and the studies that cited the included studies were examined through the Scopus database. Furthermore, relevant review papers [12,26] and books [27] were searched for additional relevant studies. ...
... The Downs and Black checklist [28] was used for the assessment of the methodological quality of the included studies. The standard checklist has 27 items, which refer to: reporting (items 1-10); external validity (items 11-13); internal validity (items [14][15][16][17][18][19][20][21][22][23][24][25][26]; and statistical power (item 27). However, given the specificity of included studies (i.e., exercise interventions), we added two items that refer to reporting of compliance (item 28) and supervision of the exercise programs (item 29), as used in other studies [29][30][31]. ...
... As little as 2 weeks of resistance training has been shown to result in significant hypertrophy of the knee extensor muscle group [49]. However, it is possible that the hypertrophy rate is slower in response to aerobic training [26]. Therefore, Konopka and Harber suggested that to achieve similar muscular growth, aerobic training frequency should be higher than the resistance training frequency [12]. ...
Background
Currently, there are inconsistencies in the body of evidence for the effects of resistance and aerobic training on skeletal muscle hypertrophy.
Objective
We aimed to systematically review and meta-analyze current evidence on the differences in hypertrophic adaptation to aerobic and resistance training, and to discuss potential reasons for the disparities noted in the literature.
Methods
The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed for this review. The Downs and Black checklist was used for the assessment of methodological quality of the included studies. A random-effects meta-analysis was employed. In total, three analyses were performed: (1) for whole-muscle knee extensor data; (2) for type I fiber cross-sectional area; and (3) for type II fiber cross-sectional area.
Results
The final number of included studies in the present review is 21. All studies were of good or moderate methodological quality. The meta-analysis for whole-muscle hypertrophy resulted in a significant pooled difference (p < 0.001) in responses between the aerobic training and resistance training interventions. The pooled Hedge’s g, favoring resistance over aerobic training, was 0.66 (95% confidence interval 0.41–90; I2 = 0%). The meta-analysis for type I fiber cross-sectional area data resulted in a significant pooled difference (p < 0.001) between the aerobic training and resistance training groups. The pooled Hedge’s g, favoring resistance training over aerobic training, was 0.99 (95% confidence interval 0.44–1.54; I2 = 24%). The meta-analysis of type II fiber cross-sectional area data resulted in a significant pooled difference (p < 0.001) between the aerobic training and resistance training groups. The pooled Hedge’s g, favoring resistance training over aerobic training, was 1.44 (95% confidence interval 0.93–1.95; I2 = 8%).
Conclusions
The results of this systematic review and meta-analysis suggest that single-mode aerobic training does not promote the same skeletal muscle hypertrophy as resistance training. This finding was consistent with measurements of muscle hypertrophy both at the whole-muscle and myofiber levels. While these results are specific to the knee extensor musculature, it can be hypothesized that similar results would be seen for other muscle groups as well.
... The effects of resistance training, aiming hypertrophy, promotes better results than the effect of endurance training 12 . Studies report that resistance training induces hypertrophy and increases muscular strength in Elder individuals [13][14][15][16] . That way, the evidences suggest that in menopausal women, resistance exercise increases muscle and bone mass, contributes to reduce the fat mass and fights against inflammatory conditions which are typical of this population 11,17 . ...
... In the present study the mechanisms by which resistance exercise with weight results in lower scores of anxiety and depression were not investigated. However, it is possible that, together, the alterations which come from the practice of resistance exercise, such as increase or preservation of lean mass, decrease of body fat and inflammatory state, improvements in the metabolic and cardiovascular function associated with a better functional capacity and sociability are the possible causal factors 11,13,16,31 . Considering the central nervous system, it has been demonstrated that the exercise is associated with structural changes in limbic brain areas related to emotions and cognition 20,30,32 . ...
This study aimed to compare levels of anxiety and depression of middle-aged women trained in resistance exercise and
sedentary. Forty women, 20 exercised (GT) and 20 non-exercised (CG) (GT = 56.9 ± 6.6 years, 27.3 ± 4.8 kg/m2
), (CG =
51.5 ± 5.0 years, 27.0 ± 7.7 kg/m2
) underwent the study. The participants answered the HAD scale with 14 questions related
to levels of anxiety and depression. The CG had higher scores of depression and anxiety than GT. The results for anxiety (GT
= 5.2 ± 2.7, CG = 9.5 ± 4.0) and depression (GT = 4.1 ± 2.6, CG = 7.7 ± 4.0) differed significantly (P<0.05) between groups.
Middle-Aged women who participated in a resistance exercise program presented a better mental health as evidenced by a
lower levels of depression and anxiety in relation to sedentary counterpartners.
Keywords: Resistance exercise. Elderly. Anxiety. Depression.
... Ozaki et al. (49) report increased aerobic fitness as a result of resistance training, and Steele et al. (63) conclude that resistance training performed at maximal effort (e.g., reaching momentary failure) may optimize these improvements. Lundberg et al. (40) have also reported augmented hypertrophic outcomes from the performance of maximal effort cycling, and a range of other authors have reported improved strength and hypertrophy from aerobic modalities (34,48,50). ...
... Previous research supports that high effort resistance training performed as HIIT can result in strength adaptations (9). Although improvements in strength as a result of aerobic-based exercise modes, particularly higher effort protocols, have been reported, they are considered to be greatest in untrained and older populations (34,48,50). We might consider that aerobic exercise, if performed to a high effort, might provide a stimulus akin to the performance of low load resistance training, which evidence suggests is efficacious in increasing strength and hypertrophy when also performed to a high effort (i.e., momentary failure; [45,57,58]). ...
Powerlifters and strongman athletes have a necessity for optimal levels of muscular strength whilst maintaining sufficient aerobic capacity to perform and recover between events. HIIT has been popularized for its efficacy in improving both aerobic fitness and strength but never assessed within the aforementioned population group. The present study looked to compare the effect of exercise modality, e.g. a traditional aerobic mode (AM), and strength mode, (SM), during HIIT upon aerobic fitness and strength. Sixteen well resistance trained male participants, currently competing in powerlifting and strongman events, completed 8 weeks of approximately effort- and volume-matched HIIT in 2 groups: AM (cycling, n=8) and SM (resistance training, n=8). Aerobic fitness was measured as predicted V O_2Max using the YMCA 3 minute step test and strength as predicted 1RM from a 4-6RM test using a leg extension. Both groups showed significant improvements in both strength and aerobic fitness. There was a significant between-group difference for aerobic fitness improvements favoring the AM group (p<0.05). There was no between-group difference for change in strength. Magnitude of change using within group effect size (ES) for aerobic fitness and strength were considered large for each group (aerobic fitness, AM = 2.6, SM = 2.0; strength, AM = 1.9, SM = 1.8). In conclusion, our results support enhanced strength and aerobic fitness irrespective of exercise modality (e.g. traditional aerobic and resistance training). However, powerlifters and strongman athletes wishing to enhance their aerobic fitness should consider HIIT using an aerobic HIIT mode.
... At the point of failure, the magnitude of metabolic fatigue would be greater for resistance training with lower loads compared to higher loads, given that one cannot continue lifting even with lighter weights. This greater metabolic fatigue may compensate for the lower mechanical stress [8] and may also explain why activities such as cycling and walking have also been shown to stimulate muscle growth to varying magnitudes [9,10]. In addition, blood flow restriction (BFR) applied to the working muscles during these activities induces greater hypertrophic effects albeit at the same level of mechanical stress [11,12], which would suggest a possible contribution from metabolic stress. ...
... Aerobic exercise such as cycling and walking have also been shown to stimulate muscle growth to varying magnitudes for limited muscles (working muscles) or age groups [9,10]. Mikkola et al. compared the hypertrophic effect between high-load resistance training ($80% 1RM) and cycling (exercise intensity from aerobic to anaerobic threshold) [17]. ...
This paper reviews the existing evidence for the potential contribution of metabolic and mechanical stimuli to muscle growth in response to a variety of exercise modalities and intensities. Recent research has demonstrated that low-load resistance training can elicit comparable hypertrophy to that of high-load resistance training when each set is performed until failure. The degree of metabolic fatigue would be greater for resistance training with lower loads compared to higher loads at the point of muscle failure, which may compensate for the lower mechanical stress. This may also explain why muscle hypertrophy occurs to varying magnitudes when activities such as cycling and walking are performed. Furthermore, the application of blood flow restriction to the working muscles during these activities induces greater hypertrophy albeit at the same level of mechanical stress, which would suggest a possible contribution from metabolic stress. Thus, it is plausible that both mechanical and metabolic stimuli are primary mechanisms for muscle hypertrophy and the degree of contributions of both stimuli determines the exercise-induced muscle hypertrophy.
... Moreover, cycle training has been utilized for a broad range of populations leading to improvement of mixed muscle protein synthesis and aerobic capacity (32). During cycle exercise, a risk of muscle damage is lower due to primarily concentric muscle contraction compared to running, and muscle protein synthesis is enhanced after acute cycling or chronic cycling (26).Another benefit of cycle training is that it minimizes the loading stress on joints due to the fact that body weight is supported by the seat of the bicycle ergometer, thus reducing the weight bearing placed on the joints compared to other exercises (8). ...
... In addition, a review article reported that even though cycle training in both young and old populations elicits A C C E P T E D muscle hypertrophy, the rate of muscle hypertrophy is slower than resistance exercise and longer training periods are required to induce muscle hypertrophy (26). Thus, the longer training period and greater number of training sessions might influence better muscle hypertrophy responses. ...
Methods:
Thirty one physically active subjects were assigned to one of three groups: VI [n = 10, 60-70% Heart Rate Reserve (HRR)], LI-BFR (n = 11, 30% HRR with BFR at 160-180 mmHg), and CON (n = 10, no exercise). Subjects in VI and LI-BFR cycled 3 times / week for 6 weeks (total 18 sessions). Body composition, muscle mass, strength, and aerobic capacity were measured pre, post, and after 3 weeks of de-training.
Results:
A group × time interaction (p = 0.019) effect for both knee flexion and leg lean mass were found. For both VI and LI-BFR groups, knee flexion strength was significantly increased between pre and post (p = 0.024, p = 0.01) and between pre and 3 week-post (p=0.039, p = 0.003), respectively. For the LI-BFR group, leg lean mass was significantly increased between pre and 3 week-post (p = 0.024) and between post and 3 week-post (p =0.013). However, there were no significant differences between groups for any variables.
Conclusions:
The LI-BFR elicits an increase in the knee flexion muscle strength over time similar to the VI. An increase in the leg lean mass over time was seen in the LI-BFR, but not in VI and CON.
... 24,25 Moreover, previous studies have shown that HIIT is likely associated with promote both anabolic and anticatabolic stimuli and stimulate muscle hypertrophy. 26 The results showed that SP alone and in combination with HIIT caused weight loss, reduced fasting blood glucose levels, increased insulin levels, and improved insulin resistance. ...
This study aimed to investigate changes in protein signaling associated with muscle regeneration in aged rats with obesity and diabetes following high-intensity interval training (HIIT) and SP supplementation. Forty male Wistar rats weighting 280-325 g were used in this study. Obesity was induced by eight weeks of a high-fat diet, and diabetes was induced by intraperitoneal injection of 40 mg/kg streptozocin. Rats were randomly divided into control (CON), sham, SP, HIIT, and HIIT+SP groups. HIIT was performed five times per week during the 8-week period. SP dose was 50 mg/kg. Real-time PCR was used to evaluate the expression of myogenin, MyoD1, and Pax7. The decreases in body mass in the HIIT, HIIT+SP and SP groups were significantly higher than those in the sham and CON groups (p=0.0001). The soleus muscle mass increased significantly only in the HIIT and HIIT+SP groups (p<0.01). HIIT+SP improved fasting blood glucose and insulin levels more than HIIT alone and SP (p<0.05), while HIIT increased the expression levels of myogenic factors more than other groups (p=0.0001). In conclusion HIIT alone had a significant impact on myogenic factors, whereas Spirulina had an effect only when combined with HIIT.
... However, it should be noted that while CT groups (CTM, CTH, RTC) were time-matched, the RT group had two less sessions per week. Thus, while the addition of AT generally did not lead to a meaningful net effect on strength and hypertrophy, it should be considered that AT can contribute to hypertrophy and strength (Ozaki et al., 2015); thus, it may be that the combined effect of RT + additional AT counteracted the interference effect in the present study. ...
The purpose of this investigation was to compare the effects of three different concurrent training (CT) programs and a resistance training (RT) program. Twenty-three resistance trained men (age: 24 ± 3 years) were randomized into four groups: concurrent RT and high intensity interval cycling (CTH, n = 6), concurrent RT and moderate intensity continuous cycling (CTM, n = 5), RT and barbell circuit training (RTC, n = 6), or RT only (RT, n = 6). Back squat and bench press strength, quadriceps, and pectoralis muscle thickness, VO2peak, and maximum workload (Wmax, Watts) were assessed. Squat strength gains were meaningful in all groups and comparable among CTH (16.88 kg [95% CrI: 11.15, 22.63]), CTM (25.54 kg [95% CrI: 19.24, 31.96]), RTC (17.5 kg [95% CrI: 11.66, 23.39]), and RT (20.36 kg [95% CrI: 15.29, 25.33]) groups. Bench press strength gains were meaningful in all groups and comparable among CTH (11.86 kg [95% CrI: 8.28, 15.47]), CTM (10.3 kg [95% CrI: 6.49, 14.13]), RTC (4.84 kg [95% CrI: 1.31, 8.47]), and RT (10.16 kg [95% CrI: 7.02, 13.22]) groups. Quadriceps hypertrophy was meaningful in all groups and comparable among CTH (2.29 mm [95% CrI: 0.84, 3.76]), CTM (3.41 mm [95% CrI: 1.88, 4.91]), RTC (2.6 mm [95% CrI: 1.17, 4.05]), and RT (2.83 mm [95% CrI: 1.55, 4.12]) groups. Pectoralis hypertrophy was meaningful in CTH (2.29 mm [95% CrI: −0.52, 5.1]), CTM (5.14 mm [95% CrI: 2.1, 8.15]), and RTC (7.19 mm [95% CrI: 4.26, 10.02]) groups, but not in the RT group (1 mm [95% CrI: −1.59, 3.59]); further, between-group contrasts indicated less pectoralis growth in the RT compared to the RTC group. Regarding cardiovascular outcomes, only the RTH and RTM groups experienced meaningful improvements in either measure (VO2peak or Wmax). These data suggest that the interference effect on maximal strength and hypertrophy can be avoided when the aerobic training is moderate intensity cycling, high intensity cycling, or a novel barbell circuit for ~one hour per week and on non-RT days. However, the barbell circuit failed to elicit meaningful cardiovascular adaptations.
... The differences observed between the present study and the interventions with HIIT could be due to the great disparity of TID, the duration of the training protocols, and the fact that HIIT is much more stressful and does not allow a large training volume. Therefore, Z1 and Z2 training time may have had a greater effect on reducing fat mass in the present study, and HIIT, while also contributing to fat mass loss, appears to have a greater effect on increasing fat-free mass [24,25]. ...
Citation: Magalhães, P.M.; Cipriano, F.; Morais, J.E.; Bragada, J.A. Effects of a 16-Week Training Program with a Pyramidal Intensity Distribution on Recreational Male Cyclists. Sports 2024, 12, 17. https://doi. Abstract: Different training intensity distributions (TIDs) have been proposed to improve cycling performance, especially for high-competition athletes. The objectives of this study were to analyze the effect of a 16-week pyramidal training intensity distribution on somatic and power variables in recreational cyclists and to explore the training zone with the greatest impact on performance improvement. The sample consisted of 14 male recreational cyclists aged 41.00 ± 7.29 years of age. A number of somatic variables were measured. During an incremental protocol, power at a 4 mMol·L −1 blood lactate concentration (P4), corresponding power to body mass ratio (P/W P4), and heart rate (HR P4) were also measured. Among the somatic variables, the percentage of fat mass showed the greatest improvement between moments (p < 0.001, d = 0.52). Both P4 (p < 0.001, d = 1.21) and P/W P4 (p < 0.001, d = 1.54) presented a significant increase between moments. The relative improvement in P4 (% P4) showed a significant correlation (R s = 0.661, p = 0.038) and relationship (R 2 = 0.61, p = 0.008) mainly with training zone Z2 (blood lactate levels ≥ 2 and <4 mMol·L −1). It seems that spending more time in Z2 promoted an improvement in both somatic and power variables in recreational cyclists.
... Studies in other populations have reported improvements in muscle hypertrophy, and thus, in muscle strength among younger and older adults after engaging in a single type and mode of physical exercise that includes walking 43,44 and riding a bicycle 45,46 , which is consistent with the findings of this review. www.nature.com/scientificreports/ ...
Therapeutic exercise exerts positive effects by mitigating or reducing the motor or cognitive changes that people with Down syndrome undergo throughout their life. There are no updated systematic reviews that integrate the evidence available in a way that facilitates decision-making for physical rehabilitation teams. This study therefore aimed to consolidate the information available and compare the effects of different types of physical exercise on the motor function of adults with DS. We conducted a systematic review and meta-analysis of randomized clinical trials and quasi-experimental studies. The literature search was performed between January 2023 and February 2023 using the PubMed, SCIELO, Epistemonikos, and Lilacs databases. Studies were selected according to pre-determined inclusion and exclusion criteria. The risk-of-bias assessment was performed using the risk-of-bias rating tool for randomized clinical trial (RoB) and the risk of bias of non-randomized comparative studies was assessed using the risk of bias in non-randomized studies of interventions (ROBINS-I) tool. Risk-of-bias assessment and meta-analyses were performed using the RevMan software package. Sixteen studies met the eligibility criteria for the qualitative synthesis and 4 were included in the meta-analyses. Combined exercise significantly increased muscle strength both in the upper limbs (SMD = 0.74 [95% CI 0.25–1.22]) and lower limbs (SMD = 0.56[95% CI 0.08–1.04]). Aerobic exercise improved spatiotemporal gait parameters. Aerobic exercise showed significant improvements in dynamic balance while combined exercise significantly increased dynamic and static balance. The certainty of the evidence was low to moderate for all outcomes. There was low and moderate certainty of evidence for the outcomes proposed in this review. However, therapeutic exercise could be effective in improving muscle strength and gait functionality.
... A review of potential mechanisms underpinning the benefits of exercise therapy on pain and function in OA found that an increase in upper leg strength, a decrease of extension impairments, and an improvement in proprioception, were all possible mediators of the link between exercise and a decrease in OA symptoms in the lower limb; another review highlighted the need to address muscle weakness in people with hip OA [12,13]. Cycling has been found to improve balance and proprioception, induce muscle hypertrophy, directly improve muscle weakness and therefore upper leg strength, and (because it is non-weight-bearing) causes less stress on the joints than running or other impact sport [14][15][16]. ...
Background
Osteoarthritis (OA) is a chronic degenerative joint disorder for which there is no known cure. Non-surgical management for people with mild-to-moderate hip OA focuses mainly on alleviating pain and maximising function via the National Institute for Health and Care Excellence (NICE) recommended combination of education and advice, exercise, and, where appropriate, weight loss. The CHAIN (Cycling against Hip pAIN) intervention is a group cycling and education intervention conceived as a way of implementing the NICE guidance.
Methods
CycLing and EducATion (CLEAT) is a pragmatic, two parallel arm, randomised controlled trial comparing CHAIN with standard physiotherapy care for the treatment of mild-to-moderate hip OA. We will recruit 256 participants referred to the local NHS physiotherapy department over a 24-month recruitment period. Participants diagnosed with hip OA according to NICE guidance and meeting the criteria for GP exercise referral will be eligible to participate. Primary outcome is the difference in Hip Disability and Osteoarthritis Outcome Score (HOOS) function, daily living subscale between those receiving CHAIN and standard physiotherapy care. Secondary outcomes include performance-based functional measures (40 m walking, 30s chair stand and stair climb tests), ability for patient to self-care (patient activation measure) and self-reported health-related resource use including primary and secondary care contacts. The primary economic endpoint is the number of quality adjusted life years (QALYs) at 24 weeks follow-up. The study is funded by the National Institute for Health Research, Research for Patient Benefit PB-PG-0816-20033.
Discussion
The literature identifies a lack of high-quality trials which inform on the content and design of education and exercise in the treatment of patients with hip OA and explore cost-effectiveness. CLEAT is a pragmatic trial which seeks to build further evidence of the clinical benefits of the CHAIN intervention compared to standard physiotherapy care within a randomised, controlled trial setting, and examine its cost-effectiveness.
Trial registration number
ISRCTN19778222. Protocol v4.1, 24th October 2022.
... A review of potential mechanisms underpinning the bene ts of exercise therapy on pain and function in OA found that an increase in upper leg strength, a decrease of extension impairments, and an improvement in proprioception, were all possible mediators of the link between exercise and a decrease in OA symptoms in the lower limb; another review highlighted the need to address muscle weakness in people with hip OA [12,13]. Cycling has been found to improve balance and proprioception, induce muscle hypertrophy, directly improve muscle weakness and therefore upper leg strength, and (because it is non-weight-bearing) causes less stress on the joints than running or other impact sport [14][15][16]. ...
Background
Osteoarthritis (OA) is a chronic degenerative joint disorder for which there is no known cure. Non-surgical management for people with mild-to-moderate hip OA focuses mainly on alleviating pain and maximising function via the National Institute for Health and Care Excellence (NICE) recommended combination of education and advice, exercise, and, where appropriate, weight loss. The CHAIN (Cycling against Hip pAIN) intervention is a group cycling and education intervention conceived as a way of implementing the NICE guidance.
Methods
CycLing and EducATion (CLEAT) is a pragmatic, two parallel arm, randomised controlled trial comparing CHAIN with standard physiotherapy care for the treatment of mild-to-moderate hip OA. We will recruit 256 participants referred to the local NHS physiotherapy department over a 24-month recruitment period. Participants diagnosed with hip OA according to NICE guidance and meeting the criteria for GP exercise referral will be eligible to participate. Primary outcome is the difference in HipDisability and Osteoarthritis Outcome Score (HOOS) function, daily living subscale between those receiving CHAIN and standard physiotherapy care. Secondary outcomes include performance-based functional measures (40m walking, 30s chair stand and stair climb tests), ability for patient to self-care (patient activation measure) and self-reported health-related resource use including primary and secondary care contacts. The primary economic endpoint is the number of quality adjusted life years (QALYs) at 24 weeks follow-up. The study is funded by the National Institute for Health Research, Research for Patient Benefit PB-PG-0816-20033.
Discussion
The literature identifies a lack of high-quality trials which inform on the content and design of education and exercise in the treatment of patients with hip OA and explore cost-effectiveness. CLEAT is a pragmatic trial which seeks to build further evidence of the clinical benefits of the CHAIN intervention compared to standard physiotherapy care within a randomised, controlled trial setting, and examine its cost-effectiveness.
Trial registration number
ISRCTN19778222. Protocol v4.1, 24th October 2022
... The findings on muscle hypertrophy using muscle cross-section areas highlight a few benefits of the BFRT plus EX program in some studies (Abe et al. 2006(Abe et al. , 2010Freitas et al. 2017;BjØrnsen et al. 2019;Centner et al. 2020) but not for the occlusion training before 6 weeks. Studies (Abe et al. 2006;Yamanaka et al. 2012;Kim et al. 2016) stated that large duration and a greater number of training sessions can only induce muscle hypertrophy in the athletic population as the rate of muscle hypertrophy by kaatsu walking, kaatsu cycling, or kaatsu low-load resistance training is slower than resistance exercise (Ozaki et al. 2015). ...
Background:
The benefits of Blood Flow Restriction Therapy (BFRT) have gained attention in recent times.
Objective:
This review aimed to evaluate the immediate (up to 24 hours), intermediate (up to 6 weeks), and long term (6-10 weeks) effects of BFRT plus exercises (EX) compared to EX only on athletic performance (sprint and jump performance), muscle strength, and hypertrophy in athletes and physically active population.
Methods:
A literature search was conducted to select randomized controlled trials across four electronic databases from inception till April 2021. The search yielded twenty-seven studies in total.
Results:
Based on eligibility criteria, twenty-one studies were analyzed. No differences were found between both groups for immediate (standardized mean difference [SMD] -0.02, 95% confidence interval [CI] -0.31, 0.27) and long-term effects (SMD -0.30, 95%CI -0.90, 0.30) on sprint performance. For jump performance, no significant effect was observed immediately (SMD -0.02 (95% CI -1.06, 1.02) and long term (SMD -0.40 (95% CI -1.46, 0.67). Similarly, muscle torque at intermediate (SMD 0.90 (95% CI -1.01, 2.81) and long term (SMD -0.54 (95% CI -1.19, 0.12), muscle strength at intermediate (SMD 1.12 (95% CI 0.20, 2.04) , and long term (SMD -0.07 (95% CI -0.56, 0.42) also showed non-significant effects. Muscle hypertrophy at intermediate (SMD 0.16 (95% CI -0.31, 0.63) and long term (SMD -0.20 (95% CI -0.90, 0.50) were not statistically significant.
Conclusions:
There was no significant difference observed in BFRT plus EX group compared to the EX-group on athletic performance, muscle strength, and muscle hypertrophy.
... Glycogen synthase kinase 3β (GSK3β) is a regulator of CUGBP1 activity through cyclin D3-dependent kinase 4 (31). Therefore, we further examined protein levels of phosphorylated GSK3β (p-GSK3β Ser9 ) and total GSK3β some evidence supports the role of aerobic training on skeletal muscle hypertrophy (30). Thus, we investigated the influence of cycling on total lean mass (TLM) in DM1 patients. ...
Background:
Myotonic dystrophy type 1 (DM1) is a complex life-limiting neuromuscular disorder characterized by severe skeletal muscle atrophy, weakness, and cardio-respiratory defects. Exercised DM1 mice exhibit numerous physiological benefits that are underpinned by reduced CUG foci and improved alternative splicing. However, the efficacy of physical activity in patients is unknown.
Methods:
Eleven genetically diagnosed DM1 patients were recruited to examine the extent to which 12-weeks of cycling can recuperate clinical, and physiological metrics. Furthermore, we studied the underlying molecular mechanisms through which exercise elicits benefits in skeletal muscle of DM1 patients.
Results:
DM1 was associated with impaired muscle function, fitness, and lung capacity. Cycling evoked several clinical, physical, and metabolic advantages in DM1 patients. We highlight that exercise-induced molecular and cellular alterations in patients do not conform with previously published data in murine models and propose a significant role of mitochondrial function in DM1 pathology. Lastly, we discovered a subset of small nucleolar RNAs (snoRNAs) that correlated to indicators of disease severity.
Conclusion:
With no available cures, our data supports the efficacy of exercise as a primary intervention to partially mitigate the clinical progression of DM1. Additionally, we provide evidence for the involvement of snoRNAs and other noncoding RNAs in DM1 pathophysiology.
Trial registration:
This trial was approved by the HiREB committee (#7901) and registered under ClinicalTrials.gov (NCT04187482).
Funding:
This work was primarily supported by Neil and Leanne Petroff. This study was also supported by a Canadian Institutes of Health Research Foundation Grant to MAT (#143325).
... Although strength improvements after resistance training protocols are well documented [3], some studies have already shown strength increases after HIIT protocol [12,13]. The increases in muscle strength observed in HIIT can be attributed to the intensity at which the exercise was performed [41]. It has been suggested that the increase in strength after high-intensity training is due to the greater recruitment of motor units, which increases in higher running speeds, reaching levels above those of a maximum voluntary contraction [42,43], resulting in greater recruitment of type II muscle fibers [19]. ...
Purpose
The aim of this study was to compare the effects of 8 weeks of resistance training (RT) and high-intensity interval training (HIIT) on muscle strength, muscle power and cardiorespiratory responses in trained young men.
Methods
Twenty-two men [RT (n = 11); HIIT (n = 11)] performed 8 weeks of training, with frequency of 2 times per week. RT group performed 10 sets × 10–12 RM of Leg-press exercise, while HIIT group performed 10 sets of running × 60 s at 85–95% of maximal heart rate. Both groups performed 60 s of passive rest between sets. Maximal strength (one-repetition maximum [1RM] of Leg Press and Knee Extension), jump height (single-leg countermovement jump) and cardiorespiratory responses during Conconi Test (predicted VO2peak and heart rate at maximal and at deflection point) were evaluated at baseline and after training program.
Results
1RM of Leg Press increased in both training groups (p < 0.001), with higher gains in the RT group (RT = 32.2%, HIIT = 9.5%; p = 0.036; d = 1.86), 1RM of Knee Extension did not improve for either group (p = 0.065). Only the HIIT group improved jump height (RT = − 1.5%, HIIT = 14.2%; p = 0.002; d = 1.52) and cardiorespiratory capacity (RT = − 1.1%, HIIT = 3.2%; p = 0.006; d = 1.27).
Conclusion
Despite RT group promoting higher strength gains, HIIT is also effective for improving strength, jump height and cardiorespiratory capacity, and it presents as a possible alternative for people who seek improvements in health variables.
Trial registration
This study was registered in Brazilian Clinical Trials Registry (registration number RBR-7n8y9ky) on Mar 09th 2021 (retrospectively registered).
... The number of myofibrils increases with RT, especially the fast-twitch fibers, thus increasing the cross-sectional area of the fibers and thereby increasing muscle mass [47]. In addition to increasing the aerobic metabolism of muscular fibers, aerobic training can increase muscle mass [48] in a similar way to RT, but it takes a longer period of time and more frequent sessions than resistance RT [49,50]. The effect size of RT was greater for grip strength than aerobic training, while both could improve upper and lower limb strength. ...
Background:
Sarcopenia has been recognized as an inevitable part of aging. However, its severity and the age at which it begins cannot be predicted by age alone. The condition can be categorized into primary or age-related sarcopenia and secondary sarcopenia. Sarcopenia is diagnosed as primary when there are no other specific causes. However, secondary sarcopenia occurs if other factors, including malignancy or organ failure, are evident in addition to aging. The prevalence of secondary sarcopenia is far greater than that of primary sarcopenia and requires special attention. To date, nutrition and exercise have proven to be the best methods to combat this disease. The impact of exercise on subjects suffering from sarcopenia with a specific morbidity is worthy of examination for understanding and prevention. The purpose of this review, therefore, is to summarize recent research that has investigated the impact of exercise in patients with secondary sarcopenia, specifically with one comorbidity.
Methods:
Pubmed, Web of Science, Embase and Medline databases were searched comprehensively with no date limit for randomized controlled trials. The literature was specifically searched for clinical trials in which subjects were sarcopenic with only one comorbidity participating in an exercise intervention. The most visible comorbidities identified and used in the search were lung disease, kidney disease, heart disease, type 2 diabetes, cancer, neurological diseases, osteoporosis and arthritis.
Results:
A total of 1752 studies were identified that matched the keywords. After removing duplicates, there were 1317 articles remaining. We extracted 98 articles for full screening. Finally, we included 21 relevant papers that were used in this review.
Conclusion:
Despite a strong rationale for using exercise to improve muscle mass, quality or physical function in subjects with cancer, type 2 diabetes, kidney disease, lung disease and many more, baseline sarcopenia evaluation has been reported in very few trials. The limited number of studies does not allow us to conclude that exercise can improve sarcopenia in patients with other comorbidities. This review highlights the necessity for wide-ranging research initiatives involving secondary sarcopenic patients.
... There is a linear relationship between the number of repetitions and the recovery of motor function, because through the repetition it is possible to stimulate cerebral reorganization (Kreisel, Hennerici, & Bäzner, 2006). Besides that, repetitive movements performed in cycling can generate a minimal necessary stimulus to increase the activation of muscle fibers, enough to favor an increase in muscle protein synthesis (Ozaki, Loenneke, Thiebaud, & Abe, 2015). ...
Background:
Studies demonstrate the benefits of upper limbs cycle ergometer (ULCE) in subacute and chronic stroke subjects, but the literature still needs to explore the acute phase of the disease.
Objective:
Verify the effects of ULCE on muscular strength, trunk control and independence of post-stroke subjects in hospital acute phase.
Methods:
In this randomized clinical trial participants were allocated into two groups. The control group (CG) performed two daily sessions of conventional physiotherapy, while the intervention group (IG) had one daily session of conventional physiotherapy and one of ULCE. The interventions were carried out for 20 minutes for five days. Both groups were assessed before and after the treatment for upper limbs strength by manual dynamometer, trunk control by Trunk Impairment Scale and level of independence by the Modified Rankin Scale.
Results:
Twenty subjects with mean ages of 63.5±4.5 were enrolled. There was a significant intra-group difference of palmar grip, shoulder abductors, elbow flexor and wrist extensor strength, trunk control and functional independence only in IG. Inter-group difference for all variables showed superiority in IG.
Conclusions:
ULCE is an effective device for increasing muscle strength, trunk control and consequently improving the independence of post-stroke subjects in the acute hospital phase.
... On the other hand, significantly better performance was noted in muscle functions (Arm curl and Chair Stand), in walking speed (5-Meter Walk Test), and in balance (Four Square Step Test and Timed Up and Go Test) in the riding group as compared to the control group. This result was not surprising, as bicycling requires the muscular function of the lower limbs to support the weight of the rider during stoppage time and provide power for pedaling during acceleration (Ozaki et al., 2015). Moreover, the muscular function of the upper limbs is important for providing muscular forces to grasp the handlebars during braking. ...
Background: Bicycling is a good mode of transportation for people of all ages. The ability to ride a bicycle requires sufficient physical abilities. This study aimed to examine the relationship between functional fitness and the ability to ride a bicycle for community-dwelling older adults in Japan. Methods: Forty-eight older adults (13 males, 35 females) were divided into a riding group (those who could ride a bicycle; n = 34) and a control group (those who could not; n = 14). A binomial logistic regression analysis was conducted with the ability to ride a bicycle as the dependent variable and Arm Curl Test, Chair Stand Test, Back Scratch Test, Sit and Reach Test, Functional Reach Test, One Leg-Stand Test, Four Square Step Test, 5 Meter Walk Test, and Timed Up and Go Test as independent variables. Results: The results of binomial logistic regression analysis showed that, from among various functional fitness test results, only Timed Up and Go scores (odds ratio: 0.29; 95% CI 0.12–0.68) were associated with bicycle riding ability. Conclusion: These results indicated that Timed Up and Go scores are useful for predicting the ability of older adults to use a bicycle as a means of transportation.
... Sonuçlar bisiklet egzersizinin yaşlı bireylerin yanı sıra bazı hastalıklarda alt ekstremite kas kuvvetini ve aerobik kapasiteyi arttırdığını ortaya koymuştur. [7][8][9][10] Yüksek şiddetli intervalli bisiklet eğitimi orta şiddetli eğitim ile karşılaştırıldığında, daha kısa egzersiz sürelerine rağmen kilo kontrolünde, insulin direncini azaltmada ve aerobik kapasiteyi geliştirmede daha etkin sonuçlar vermiştir. [10][11][12] Bisiklet sporcusu olan Johnny Goldberg ve John Baudhin 1991 yılında normal bisiklet tecrübesini iç ortama aktarmak ve egzersiz yapmak amacıyla spinning bisikletini tasarlamışlardır. ...
Purpose: Our aim was to investigate of effects of spinning and moderate intensity cycle ergometer trainings on isokinetic knee muscle strength and endurance in sedentary females. Methods: Trial was completed with total 54 individuals, 27 sedentary females for each group. One group participated in individualized cycle ergometer training, the other group did spinning as a group exercise. Trainings lasted for 8 weeks, 3 days a week with 45 minutes sessions. Concentric and eccentric muscle strength in 60°/sec and 180°/sec angle of speeds and endurance in 180°/sec of knee extensor and flexor muscles were assessed with isokinetic dynamometer. Results: Both trainings improved concentric knee extensor and flexor muscle strengths in 60°/sec and 180°/sec angle of speeds. Muscle strength improvement in 180°/sec were better in spinning group (p<0.05). Even though the eccentric strength was only improved in 60°/sec in favour of cycle ergometer, the effect size of this improvement was too small (p<0.05, Cohen's d<0.20). Both trainings improved knee extensor and flexor muscle endurance (p<0.05). The improvements were better in spinning group for both concentric and eccentric knee extensor endurance (p<0.05). Conclusion: Results have shown that moderate intensity cycle ergometer and spinning trainings improve knee extensor and flexor muscle strength and endurance in sedentary females. Muscle strength and endurance improvements were higher in high angle of speeds among subjects after spinning training.
... The adaptations in cardiorespiratory fitness typically thought to occur as a result of modalities of exercise such as cycling also have been reported to occur as a result of resistance training, though primarily if intensity of effort is sufficiently high (i.e., to momentary failure; Steele et al., 2012) and seemingly irrespective of the manipulation of other variables (i.e., load, set volume, rest periods, and frequency; Ozaki et al., 2013a). Conversely, the adaptations in strength and hypertrophy thought typically to occur from resistance training modalities of exercise have been found to occur as a result of 'cardio' modalities (Konopka & Harber, 2014), though again this seems primarily to be the case if they are performed with a high effort (i.e., combined with blood flow restriction, or with close proximity to failure such as interval training or sprinting; De Oliviera et al., 2016;Lundberg et al., 2013;Ozaki et al., 2015;Ozaki et al., 2013b). Despite this, studies directly comparing resistance training and 'cardio' training modalities upon these chronic adaptations contrast in their findings with some showing certain adaptations to be similar (Messier & Dill, 1985;Sawczyn et al., 2015;Hepple et al., 1997;Jubrias et al., 2001) and others showing some adaptations to differ (Hepple et al., 1997;Jubrias et al., 2001;Farup et al., 2012;Goldberg, Elliot & Kuehl, 1994;Wilkinson et al., 2008). ...
The present study examined the effects of exercise utilising traditional resistance training (leg press) or 'cardio' exercise (recumbent cycle ergometry) modalities upon acute physiological responses. Nine healthy males underwent a within session randomised crossover design where they completed both the leg press and recumbent cycle ergometer conditions. Conditions were approximately matched for effort and duration (leg press: 4 × 12RM using a 2 s concentric and 3 s eccentric repetition duration controlled with a metronome, thus each set lasted 60 s; recumbent cycle ergometer: 4 × 60 s bouts using a resistance level permitting 80-100 rpm but culminating with being unable to sustain the minimum cadence for the final 5-10 s). Measurements included VO 2 , respiratory exchange ratio (RER), blood lactate, energy expenditure, muscle swelling, and electromyography. Perceived effort was similar between conditions and thus both were well matched with respect to effort. There were no significant effects by 'condition' in any of the physiological responses examined (all p > 0.05). The present study shows that, when both effort and duration are matched, resistance training (leg press) and 'cardio' exercise (recumbent cycle ergometry) may produce largely similar responses in VO 2 , RER, blood lactate, energy expenditure, muscle swelling, and electromyography. It therefore seems reasonable to suggest that both may offer a similar stimulus to produce chronic physiological adaptations in outcomes such as cardiorespiratory fitness, strength, and hypertrophy. Future work should look to both replicate the study conducted here with respect to the same, and additional physiological measures, and rigorously test the comparative efficacy of effort and duration matched exercise of differing modalities with respect to chronic improvements in physiological fitness.
... walking speed, strength, range of motion). 12 Cycling can induce muscle hypertrophy and increase aerobic capacity for older adults 41 and has been reported to enhance balance and proprioception. 42 The continuous cycling motion requires repetitive end-range joint mobilisation that may help to reduce pain by mechanisms such as inhibiting reflex muscle contraction, reducing intra-articular pressure and the level of joint afferent activity. ...
Objectives
The Cycling against Hip Pain programme is a 6-week exercise and education treatment pathway for people with hip osteoarthritis. Preliminary results of the Cycling against Hip Pain programme found significant improvements in clinical and patient-reported outcome measures for patients referred from primary care. This article evaluates the effectiveness of the changes made to the pathway in a quality improvement replication programme.
Methods
The replicated Cycling against Hip Pain programme was delivered between February 2018 and September 2019 in a region of England with a high percentage of adults aged over 65 years. All participants were referred from the orthopaedic outpatient department of the funding hospital (secondary care). The programme was delivered at a local leisure centre and combined 30 min of education on osteoarthritis with 30 min of progressive static cycling, once a week for 6 weeks.
Results
The participants on the replicated Cycling against Hip Pain programme did not differ from the original cohort in terms of age or pre-programme weight, however, presented with worse hip symptoms at baseline. Consistent with the findings from the original cohort, participants demonstrated significant improvements to their Oxford Hip Score, 30-s chair stand performance, Timed Up and Go score, Hip Osteoarthritis Outcome Score function and pain, EQ5D health rating, EQ5D-5L score and pain at rest and on weight bearing. In addition, participants reported an increase in knowledge, confidence and motivation to exercise.
Conclusion
A 6-week cycling and education intervention for the treatment of hip osteoarthritis provided benefits to function, pain and quality of life for patients referred from secondary care. These results are consistent with findings from patients who were referred from primary care and further support the potential of the pathway in the conservative management of hip osteoarthritis.
... When effort is matched, studies involving different margins of loads and repetition lead to similar gains in muscle strength and size [8][9][10] and there is evidence that external loads as low as 30% of 1 RM might promote significant results in these outcomes [9,11]. This effort based approach opens the possibility of performing resistance training using non-traditional approaches and have the same results as during traditional resistance training (TRT) such as elastic bands [12][13][14], body weight exercises [15,16] and even some training models traditionally associated with aerobic activities such as cycling [9,17,18]. This evidence raised the suggestion that effort, rather than external load, might be a key determinant of training adaptations [8,10,19,20]. ...
The present article aims to compare electromyographic (EMG) activity of the knee extensors during traditional resistance training (TRT) and no load resistance training with or without visual feedback (NL-VF and NL-NF). Sixteen healthy men (age: 25.2 ± 3.6) volunteered to participate in the study. Participants visited the laboratory on three occasions involving: (1) a 10 repetition maximum test (10 RM test), (2) familiarization and (3) performance of knee extensions using TRT, NL-VF and NL-NF in a random order, with 10 min of rest between them. TRT involved the performance of a set to momentary muscle failure using the 10 RM load. NL-NF involved the performance of 10 repetitions with no external load, but with the intention to maximally contract the muscles during the whole set. NL-VF involved the same procedure as NL-NF, but a monitor was positioned in front of the participants to provide visual feedback on the EMG activity. Peak and mean EMG activity were evaluated on the vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF). Results: there were no significant differences in VM and VL peak EMG activity among different situations. There was a significant difference for peak EMG activity for RF, where TRT resulted in higher values than NL-VF and NL-NF (p < 0.05). Higher values of mean EMG activity were found for VM, VL and RF during TRT in comparison with both NL-VF and NL-NF. Conclusions: resistance training with no external load produced high levels of peak muscle activation, independent of visual feedback, but mean activation was higher during TRT. These results suggest that training with no external load might be used as a strategy for stimulating the knee extensors when there is limited access to specialized equipment. Although the clinical applications of no load resistance training are promising, it is important to perform long-term studies to test if these acute results will reflect in muscle morphological and functional changes.
... Endurance training such as walking is widely recommended as a major exercise modality for improving or maintaining aerobic capacity and cardiovascular health. Walking can also improve lower limb muscle size and strength in older adults when performed regularly for prolonged periods (i.e., over months rather than weeks) (Ozaki et al., 2015). For example, Kubo et al. investigated the effects of a 6-month progressive walking program. ...
The purpose of the present study was to investigate the effect of the progressive walking program on lower limb muscle size and strength and evaluated whether the stair-climbing exercise provided additional training effects when combined with the walking program. Fifteen elderly subjects (age 69 ± 1 years, height 1.63 ± 0.02 m, body weight 64.5 ± 2.0 kg) were randomly assigned to a walking group or a walking and stair-climbing group. The progressive walking program comprised continuous (week 1-8) and interval (week 9-17) exercises. The walking and stair-climbing group also performed stair climbing. Muscle thickness, strength, and walking performance were evaluated before and 8 and 17 weeks after the start of the program. The muscle thickness of the anterior and posterior parts of the thigh significantly (p < 0.05) increased in both groups. There was also a significant (p < 0.01) main effect of time in isometric maximal strength and the values expressed relative to body mass for both knee extension and flex-ion. However, no group × time interactions were noted. Furthermore , the percentage change of knee flexion strength after the training period was significantly (p < 0.01) correlated with the pre-intervention value. Seventeen weeks of the progressive walking program can increase thigh muscle size and strength for older adults; however, an added stair-climbing exercise may not provide additional training effects. Furthermore, the magnitude of improvement in knee flexion strength would depend on the pre-intervention value.
... gastrocnemii ACSA was predictors of the relative peakpower, coherently with their contribution reported in sprint cycling (Akima et al., 2005;Perez-Gomez et al., 2008). Interestingly, cycling exercise was shown to stimulate small increments in muscle size (Ozaki, Loenneke, Thiebaud, & Abe, 2015), thus a kind of bidirectional correlation between muscle size and regular cycling could be argued. However, it is not possible to exclude that the present participants could have been previously engaged in regular resistance training. ...
Purpose: The current study investigated the role of quadriceps and gastrocnemii size and vastus lateralis and gastrocnemius medialis muscle architecture in peak-power and time-to-peak-power exerted in an allout Wingate test. Twenty-one amateur cyclists were recruited. Methods: Quadriceps and gastrocnemii anatomical cross-sectional area (ACSA), and vastus lateralis and gastrocnemius medialis pennation angle and fascicle length were measured using ultrasound. Relative peak-power (normalized per body mass)
and time-to-peak-power were measured during a 30s all-out test. Results: Relative peak-power was correlated with quadriceps ACSA (r = 0.896, p < .001), gastrocnemii ACSA (r = 0.811, p < .001), vastus lateralis (r = 0.787, p < .001) and gastrocnemius medialis pennation angle (r = 0.638, p < .003). Multiple regression revealed that quadriceps and gastrocnemii ACSA accounted for 85% (R2= 0.85) of peak-power variance. Time-to-peak-power showed very large (r = −0.868, p < .001) and large correlation (r = −0.680, p = .001)
with VL and GM fascicle length, respectively. Multiple regression analysis revealed that VL fascicle length explained 75% (R2= 0.75) of the time-to-peak-power variance. Conclusions: Quadriceps and gastrocnemii ACSA largely explained relative peak-power in an all-out Wingate test. Vastus lateralis fascicle length was the main predictor of the time-to-peak-power. Muscle architecture characteristics seem to be involved in the power generating capacity.
... Aerobic exercise has been reported to be one of the most effective methods to keep one's health (Racil et al., 2016) (Ozaki et al., 2015) and to help prevent cardiovascular disease (Pantelic et al., 2013). Li J et al. (Li and Siegrist, 2012) reported that high level of leisure time physical activity had a beneficial effect on cardiovascular health by reducing the overall risk of incident coronary heart disease (CHD) and stroke among men and women by 20% to 30%, while moderate level of occupational physical activity might reduce 10% to 20% risk of cardiovascular disease. ...
... Resistance training increases the number of myofibrils, especially the fast-twitch fibers, which enlarges the fiber cross-sectional area and thus increases muscle mass [17]. Aerobic training increases the aerobic metabolism of muscle fibers [45] and could achieve a similar growth of muscle mass but after a longer training period and more frequent training sessions than with resistance training [46,47]. This may explain the unfavorable effect of aerobic training on muscle mass. ...
Background:
Lack of exercise is a prevalent problem in patients receiving dialysis. Although guidelines recommend these patients to undertake suitable exercise, no exercise type or intensity has been suggested, and the effect of exercise on muscle fitness in dialysis patients is not clear. This study investigated the effect of exercise on muscle fitness, including muscle mass, muscle strength, and physical performance, in patients on dialysis.
Methods:
A systematic review and a meta-analysis of randomized controlled trials (RCTs) were conducted. Five English and 4 Chinese databases were searched from their inception to July 2018. Two independent reviewers searched the different databases, selected trials, conducted bias assessment, and extracted the data.
Results:
A total of 21 RCTs meeting the inclusion criteria were included in this review. Pooled results demonstrated that resistance training significantly improved leg mass (standard mean difference [SMD] 0.34, 95% CI [0.06-0.62], p= 0.02) whereas aerobic training did not (SMD 0.87, 95% CI [-0.11 to 1.86], p = 0.08). Resistance training increased both grip strength (weighted mean difference [WMD] 4.71 kg, 95% CI [2.42-6.99], p < 0.00001) and knee extension strength (WMD 3.93 kg, 95% CI [0.59-7.28], p = 0.02) significantly. Aerobic training improved grip strength (WMD 7.70 kg, 95% CI [3.35-12.05], p= 0.005) and the time of finishing short version of the sit-to-stand test (STS; WMD -4.69 s, 95% CI [-9.01 to -0.38], p = 0.03) but with insufficient evidence. In the dimension of physical performance, both aerobic training and resistance training have some beneficial effect on improving the score of 6-min walking test (WMD 85.76 m, 95% CI [63.43-108.09], p < 0.00001; WMD 41.92 m, 95% CI [8.06-75.75], p = 0.02, respectively) and median version of STS test (WMD 4.30 repetitions, 95% CI [1.22-7.39], p = 0.006; WMD 2.60 repetitions, 95% CI [0.64-4.56], p = 0.006, respectively).
Conclusions:
Regular resistance training with a moderate to high intensity may lead to improvement in muscle mass and muscle strength of patients undergoing dialysis, especially for the trained muscles. Both aerobic training and resistance training may help dialysis patients improve physical performance.
... This fact indicated that the exercise intensity of the enduro race is vigorous; nevertheless, cycling is a more efficient form of transportation than walking and jogging regardless of total distance. Recently, cycling training has potential to induce muscle hypertrophy in addition to increasing aerobic capacity in young and older age groups [18], therefore, cycling is an alternative exercise/sports for majority of populations who cannot perform walking and jogging with a risk of orthopedic injury, as well as a beneficial exercise to offer a variation for daily physical activity. ...
Heart rate (HR) during different endurance cycling races and events are investigated for professional cyclist, however, enduro races to compete for total laps and distance covered within a fixed time using a circuit course has not yet been investigated. This study examined the heart rate (HR) and exercise intensity during an enduro cycling race. Ten male Japanese amateur cyclists performed cycling individually for at least 2 consecutive hours. HR was measured using an HR monitor during the race, and we estimated the energy expenditure (EE) during the race using the HR–VO2 relationship in advance. Exercise intensities were defined as percentages of HRmax based on ACSM exercise guideline as follows: moderate intensity, 64–76% HRmax; vigorous intensity, 77–95% HRmax. The HR during the race was 158.9 ± 10.6 bpm (86.4 ± 2.2% HRmax), and exercise intensity is categorized as vigorous intensity. The EE during the race using HR–VO2 relationship were 12.9 ± 1.2 kcal/kg/hr, which would require a large energy expenditure (EE) during the race. However, energy cost was 0.36 ± 0.04 kcal/kg/km regardless of total distance. The findings indicate that enduro cycling racing is categorized as vigorous intensity (>77% HRmax) for healthy male recreational cyclists though, cycling is an efficient form of transportation.
... However, some studies evidence that 'cardio' modalities can promote increases in muscle strength and size (Konopka & Harber, 2014;Ozaki, Loenneke, Thiebaud, & Abe, 2015;Ozaki, Loenneke, Thiebaud, Stager, & Abe, 2013), especially when training is performed at high intensities of effort (Harber et al., 2009;Lundberg, Fernandez-Gonzalo, Gustafsson, & Tesch, 2013), while on the other hand others suggest high effort resistance training is capable of improving cardiorespiratory fitness Steele, Fisher, McGuff, & Bruce-Low, 2012). Despite this, there are relatively few studies directly comparing resistance training and 'cardio' modalities whilst controlling for variable such as intensity of effort and the duration of the exercise bouts. ...
Purpose: Exercises for increasing muscle strength and cardiorespiratory fitness are traditionally prescribed separately, based on the different characteristics of the modalities and the adaptations that each typically promotes. This separation has been questioned by recent studies that suggest that the intensity of effort at which the exercise is performed seems to impart greater influence than the equipment involved. Based on this assumption, it has been proposed that ‘cardio’ training and resistance training might promote similar adaptations as long as effort and duration are equated. The objective of the present study was to compare two ‘High Intensity Interval Training’ protocols matched for effort and duration using different exercise modalities, leg press (resistance training) and cycle ergometry (‘cardio’), upon changes in muscle strength, cardiorespiratory fitness, and lower limb composition in recreationally trained men. Methods: Twenty-five trained men (28.9 ± 5.6 years, 6.6 ± 5.6 years of training experience) were randomly divided into two groups. One group performed sprint interval training on a cycle ergometer (4 sets of 30 seconds sprints) and the other performed leg press (4 sets of 10-12 repetitions to momentary failure). Both groups trained three times a week for 5 weeks. Before and after the training period, the participants performed a 10-repetition maximum (10RM) for knee extension, An incremental exercise test on a treadmill for time to exhaustion (TTE) and peak oxygen consumption (V ̇O2peak), and underwent dual energy X-ray absorptiometry to assess lower limb composition. Results: Knee extension 10RM and TTE increased in both groups with no statistically significant between group difference (p = 0.614 and p = 0.210). There was a statistically significant between group difference for change in V ̇O2peak (p = 0.023) with only the cycle ergometer group showing a significant within group increase. For all lower limb composition outcomes, changes were minimal. Conclusion: The results of the present study suggest that 5 weeks of effort and duration matched ‘High Intensity Interval Training’ using cycle ergometry ‘cardio’ or leg press resistance training may produce similar strength and endurance (TTE) adaptations. However, ‘cardio’ modality training may produce greater increases in cardiorespiratory fitness.
... The adaptations in cardiorespiratory fitness typically thought to occur as a result of modalities of exercise such as cycling also have been reported to occur as a result of resistance training, though primarily if intensity of effort is sufficiently high (i.e., to momentary failure; Steele et al., 2012) and seemingly irrespective of the manipulation of other variables (i.e., load, set volume, rest periods, and frequency; Ozaki et al., 2013a). Conversely, the adaptations in strength and hypertrophy thought typically to occur from resistance training modalities of exercise have been found to occur as a result of 'cardio' modalities (Konopka & Harber, 2014), though again this seems primarily to be the case if they are performed with a high effort (i.e., combined with blood flow restriction, or with close proximity to failure such as interval training or sprinting; De Oliviera et al., 2016;Lundberg et al., 2013;Ozaki et al., 2015;Ozaki et al., 2013b). Despite this, studies directly comparing resistance training and 'cardio' training modalities upon these chronic adaptations contrast in their findings with some showing certain adaptations to be similar (Messier & Dill, 1985;Sawczyn et al., 2015;Hepple et al., 1997;Jubrias et al., 2001) and others showing some adaptations to differ (Hepple et al., 1997;Jubrias et al., 2001;Farup et al., 2012;Goldberg, Elliot & Kuehl, 1994;Wilkinson et al., 2008). ...
The present study examined the effects of exercise utilising traditional resistance training (leg press) or ‘cardio’ exercise (recumbent cycle ergometry) modalities upon acute physiological responses. Nine healthy males underwent a within session randomised crossover design where they completed both the leg press and recumbent cycle ergometer conditions. Conditions were approximately matched for effort and duration (leg press: 4 x 12RM, recumbent cycle ergometer: 4 x 60 second sprints). Measurements included VO2, respiratory exchange ratio (RER), blood lactate, energy expenditure, muscle swelling, and electromyography. Perceived effort was similar between conditions and thus both were well matched with respect to effort. There were no significant effects by ‘condition’ in any of the physiological responses examined (all p > 0.05). The present study shows that, when both effort and duration are matched, resistance training and ‘cardio’ exercise produce largely similar physiological responses.
... The adaptations in cardiorespiratory fitness typically thought to occur as a result of modalities of exercise such as cycling also have been reported to occur as a result of resistance training, though primarily if intensity of effort is sufficiently high (i.e., to momentary failure; Steele et al., 2012) and seemingly irrespective of the manipulation of other variables (i.e., load, set volume, rest periods, and frequency; Ozaki et al., 2013a). Conversely, the adaptations in strength and hypertrophy thought typically to occur from resistance training modalities of exercise have been found to occur as a result of 'cardio' modalities (Konopka & Harber, 2014), though again this seems primarily to be the case if they are performed with a high effort (i.e., combined with blood flow restriction, or with close proximity to failure such as interval training or sprinting; De Oliviera et al., 2016;Lundberg et al., 2013;Ozaki et al., 2015;Ozaki et al., 2013b). Despite this, studies directly comparing resistance training and 'cardio' training modalities upon these chronic adaptations contrast in their findings with some showing certain adaptations to be similar (Messier & Dill, 1985;Sawczyn et al., 2015;Hepple et al., 1997;Jubrias et al., 2001) and others showing some adaptations to differ (Hepple et al., 1997;Jubrias et al., 2001;Farup et al., 2012;Goldberg, Elliot & Kuehl, 1994;Wilkinson et al., 2008). ...
The present study examined the effects of exercise utilising traditional resistance training (leg press) or 'cardio' exercise (recumbent cycle ergometry) modalities upon acute physiological responses. Nine healthy males underwent a within session randomised crossover design where they completed both the leg press and recumbent cycle ergometer conditions. Conditions were approximately matched for effort and duration (leg press: 4 × 12RM using a 2 s concentric and 3 s eccentric repetition duration controlled with a metronome, thus each set lasted 60 s; recumbent cycle ergometer: 4 × 60 s bouts using a resistance level permitting 80-100 rpm but culminating with being unable to sustain the minimum cadence for the final 5-10 s). Measurements included VO 2 , respiratory exchange ratio (RER), blood lactate, energy expenditure, muscle swelling, and electromyography. Perceived effort was similar between conditions and thus both were well matched with respect to effort. There were no significant effects by 'condition' in any of the physiological responses examined (all p > 0.05). The present study shows that, when both effort and duration are matched, resistance training (leg press) and 'cardio' exercise (recumbent cycle ergometry) may produce largely similar responses in VO 2 , RER, blood lactate, energy expenditure, muscle swelling, and electromyography. It therefore seems reasonable to suggest that both may offer a similar stimulus to produce chronic physiological adaptations in outcomes such as cardiorespiratory fitness, strength, and hypertrophy. Future work should look to both replicate the study conducted here with respect to the same, and additional physiological measures, and rigorously test the comparative efficacy of effort and duration matched exercise of differing modalities with respect to chronic improvements in physiological fitness
... Considering that muscle metabolism decreases with age leading to reduction of muscle mass, cycling would represent a plausible sport for older adults in presence of adequate medical advices. Instead, for young people, higher intensity intermittent cycling seems to be required to reach strength gain [15]. ...
In the last 15 years, it emerged that the practice of regular physical activity reduces the risks of many diseases (cardiovascular diseases, diabetes, etc.) and it is fundamental in weight control and energy consuming to contrast obesity. Different groups proposed many molecular mechanisms as responsible for the positive effects of physical activity in healthy life. However, many points remain to be clarified. In this mini-review we reported the latest observations on the effects of physical exercise on healthy skeletal and cardiac muscle focusing on muscle stem cells. The last ones represent the fundamental elements for muscle regeneration post injury, but also for healthy muscle homeostasis.
Interestingly, in both muscle tissues the morphological consequence of physical activity is a physiological hypertrophy that depends on different phenomena both in differentiated cells and stem cells. The signaling pathways for physical exercise effects present common elements in skeletal and cardiac muscle, like activation of specific transcription factors, proliferative pathways, and cytokines. More recently, post translational (miRNAs) or epigenetic (DNA methylation) modifications have been demonstrated. However, several points remain unresolved thus requiring new research on the effect of exercise on muscle stem cells.
... Many studies have shown that gains in muscle strength and size can occur with the utilization of low loads [7][8][9][10] and even during nonorthodox resistance activities, like walking [11] and cycling [12]. These studies suggest that effort, and not external load or total work might be the key determinant to training adaptations [10,13]. ...
Objectives:
To explore the acute effects of training status, movement velocity, dominance, and visual feedback on muscle activation and rating of perceived exertion (RPE) during resistance training with no external load (no-load resistance training; NLRT).
Methods:
Thirty-three men (17 untrained and 16 trained), performed elbow flexions in four NLRT sessions: 1) slow velocity with EMG visual feedback, 2) slow velocity without EMG visual feedback, 3) fast velocity with EMG feedback, and 4) fast velocity without EMG feedback. RPE was measured using the Borg Discomfort scale. EMG for the biceps and triceps were recorded for both arms.
Results:
EMG feedback had no influence on RPE. The peak and mean EMG values were not different for the biceps (93.8±11.5% and 50±13.1%) and triceps (93.7±23.9% and 49.6±16.2%). The results revealed a difference in the training status, with higher peak EMG for untrained than for trained participants (96.9±20% vs. 90.2±15.6%). However the values for mean EMG were not different between the untrained and trained (50.3±15.7% vs. 49.2±13.7%) participants. There was no difference in the peak (92.8±19% vs. 94.7±20.4%) and mean (49.8±15.0% vs. 49.7±14.5%) EMG values for the dominant and non-dominant sides. Peak EMG values were not different between faster and slower velocities (93.6±19.6% and 93.9±17.8%). However, mean EMG was higher for slower (50.5±14.4%) than for faster (48.5±15.4%) velocities. The peak and mean EMG during contractions with (93.3±17.5% and 49.5±14.1%) and without visual feedback (94.2±19.9% and 50±15.4%) were not significantly different.
Conclusion:
NLRT produces high levels of muscle activation independent of training, status, dominance, movement velocity, and visual feedback.
... Conversely, Ozaki et al. (2015) suggested that high intensity intermittent cycling may promote gains in muscle size and strength. In line with this, a recent review suggested that CT would favour muscle hypertrophy when performed using a cycle ergometer, if performed at low weekly frequency (2×/week) and low volumes at high intensity (Murach and Bagley 2016). ...
Purpose:
To compare the increases in upper- and lower-body muscle strength in premenopausal women performing resistance training (RT) alone or alongside concurrent high-intensity interval training (CT).
Methods:
Sixteen women (26-40 years) were randomly assigned into two groups that performed either RT or CT. Both groups performed the same RT program; however, CT performed additional high-intensity interval training (HIIT) on a bicycle ergometer before RT. The study lasted 8 weeks and the participants were tested for ten repetition maximum (10RM) load in elbow flexion (barbell biceps curl) and knee extension exercises pre- and post-intervention. RT was performed with 10-12 repetitions to self-determined repetition maximum in the first four weeks and then progressed to 8-10. During CT, HIIT was performed before RT with six 1-min bouts at 7-8 of perceived subjective exertion (RPE) and then progressed to eight bouts at 9-10 RPE.
Results:
Analysis of variance revealed significant increases in upper and lower body strength for both the RT and CT groups. Biceps barbell curl 10RM load increased from 12.9 ± 3.2 kg to 14 ± 1.5 kg in CT (p < 0.05) and from 13 ± 1.8 kg to 15.9 ± 2.5 kg in RT (p < 0.05), with no significant between-groups differences. Knee extension 10RM increase from 31.9 ± 11.6 kg to 37.5 ± 8.5 kg for CT (p < 0.05) and from 30.6 ± 8.6 kg to 41.2 ± 7.4 kg for RT (p < 0.05).
Conclusion:
In conclusion, performing HIIT on a cycle ergometer before resistance training does not seem to impair muscle strength increases in the knee extensors or elbow flexors of pre-menopausal women. This information should be considered when prescribing exercise sessions, since both activities may be combined without negative effects in muscle strength.
... Only one cyclist had a decline in aLM, which may have been due to reduced cycle training volume and/or a decreased participation in resistance exercise. Thus, our results have reaffirmed that chronic cycle training itself and combination of cycling and moderate-intensity resistance training may play a role to improve or preserve muscle mass in master cyclists (12). However, we did not observe a positive association between increased aLM and aBMD. ...
Before and after a follow-up period of two-years, six male master cyclists (mean age was 59 years at the start of the study, cycle training; 5-6 hrs/wk) had dual-energy X-ray absorptiometry measured body composition (i.e., areal bone mineral density [aBMD] and appendicular lean soft tissue mass [aLM]) taken. aBMD at the femoral neck and lumber spine were similar between the two measurements, but aLM (p=0.056) tended to be higher at the 2-year follow-up. There were no significant (p>0.05) associations between changes in aLM and aBMD at femoral neck or lumber spine. Male master cyclists who exercise with a mild training volume (5-6 hrs/wk) maintained aBMD at the lumber spine and femoral neck. Furthermore, aLM tended to increase over the 2-year period. Further research is necessary to determine the training volume threshold needed to maintain aBMD in master cyclists.
... In a recent review evaluating the role of muscles in the affected leg in hip osteoarthritis, Louriero et al. (2013) highlight the need to address muscle weakness. Cycle training induces muscle hypertrophy, with increased strength gains seen more favourably in older adults (Ozaki et al., 2015). In the power phase or 'downstroke' of cycling the hip, knee and ankle joints extend simultaneously for the pushing action (So et al., 2005) and, as a consequence, cycling is an excellent method of addressing and improving extension impairments in the hip, knee and ankle joints. ...
Osteoarthritis of the hip is associated with pain, stiffness and limitations to activities of daily living. The aims of this quality improvement project were to introduce a service developed to promote the self-management of hip osteoarthritis through exercise and education, and to assess the impact of the programme on pain, function and quality of life. The service was a six-week cycling and education programme.119 participants took part. Statistically significant improvements were found for Oxford Hip Score (Mean (SD) change 4.14 (95% CI (3.02, 5.25 ), p<0.001); Sit-to-stand score (mean change 3.06s 95% CI (2.33, 3.79), p<0.001); EQ5D-5L Utility (mean change 0.06 (95% CI 0.03,0.09), p<0.001); EQ5D VAS (mean change 7.05 (95% CI 4.72,9.39) p<0.001); pain on weight-bearing (WB) (mean change 1.56 (95% CI 0.77,2.36), p<0.001), HOOS function (median change (IQR) 7.35 (1.84 to 19.12), p<0.001) and TUG test (median change 1.11s (0.31 to 2.43), p<0.001). Participants reported improvements in pain and function; increased confidence in managing hip pain; and an increase in motivation to exercise. These findings were supported by a Patient and Public Involvement Forum who suggested extending the programme to eight weeks. These results suggest that the service has potential in the management of hip osteoarthritis.
... Ambulatory activity with moderate and vigorous intensities is positively associated with anterior and posterior lower-leg MT in older women (Abe et al. 2012). In addition, our subjects who performed regular cycling (Ozaki et al. 2015) and running (Oguri et al. 2004) exercise may have prevented the age-related thigh muscle mass loss. Therefore, use of the developed equations in older adults who perform different physical activity must be preceded by their validation in those populations. ...
The purpose of this study was to develop regression-based prediction equations for estimating dual-energy X-ray absorptiometry (DXA)-derived appendicular lean soft tissue mass (aLM) using ultrasound and to investigate the validity of these equations in 102 Caucasian adults aged 50 to 76 years. The subjects were randomly separated into two groups: 71 in the model-development group (41 men and 30 women) and 31 in the cross-validation group (18 men and 13 women). aLM was measured using a DXA, and muscle thickness (MT) was measured using ultrasound at 9 sites. Stepwise linear regression analysis was used to determine predictive models for DXA-derived aLM from MT variables, sex, and age. A number of ultrasound prediction equations for estimation of aLM were developed and then cross-validated in a subsample of older adults. The results indicated that ultrasound MT and MT × height can be used to accurately and reliably estimate DXA-derived aLM in older Caucasian adults.
... CET is usually a major component of any endurance exercise program that seeks to improve aerobic capacity and cardiovascular health [16]. Cycling is a healthy form of endurance exercise and, as a non-weight bearing activity, has less impact on the joints and is thus less stressful for the body than jogging or other running sports [17]. ...
As the number of older adults continues to increase worldwide, more attention is being paid to geriatric health care needs, and successful ageing is becoming an important topic in the medical literature. A preventive approach to the care of older adults is thus a priority in our aging societies. The purpose of this study was to update evidence for the health benefits of cycle ergometer training for older adults over 70. We searched online electronic databases up to September 2014 for original observational and intervention studies on the relationship between cycle ergometer training and health among older patients over 70. Twenty-five studies examined interventions aimed specifically at promoting cycling for older adults over 70. These studies reported a positive effect on the prevention of cardiovascular disease, and a significant improvement in metabolic responses. Improving functional status, muscle strength and cognitive performance are also well established. Overall, this review demonstrates a positive effect of cycle ergometer training with functional benefits and positive health outcomes for older adults over 70. Based on this evidence, clinicians can now encourage older adults to profit from the health benefits of cycle ergometer training to be able to pursue their daily activities independently.
Resistance training (RT) is a popular exercise mode and is considered an essential part of an exercise program. In current pandemic times due to the coronavirus (i.e. COVID-19) outbreak, RT practice has been strongly threatened. However, such threat might not be an inherent problem to RT, but rather to misconceptions related to RT. In the current opinion article, we provide insights to better understand RT. When analyzing current scientific evidence, it seems that RT can be performed in a safe, time-efficient and uncomplicated manner, in many different places and with few resources, which makes it fully feasible within measures adopted to control coronavirus dissemination. RT should not be sacrificed due to consequences of the coronavirus pandemic. However, it might be necessary to sacrifice some old-fashioned thoughts, rooted in beliefs that have already been overturned by science. It would be counter-productive for population health (and countries economy) to avoid RT due to the misconception that specialized equipment, fashioned programs, or resources are needed for effective programs implementation. Therefore, RT can be easily adapted to the new time and logistical challenges brought by the coronavirus outbreak. From a practical standpoint, RT could be performed using body weight, accessible materials (e.g. elastic bands, lights dumbbells and barbell) or even without external load at home or at public spaces and still result in important health benefits.
Background:
In soccer, morphological characteristics of young players are particularly important as they have a significant impact on the performance of many technical-tactical elements. Our aim in this study was to investigate whether soccer specific training on its own or combined with strength training can influence the morphological characteristics, of young soccer players and if so, to establish which age is more appropriate for interventions through individualized training.
Methods:
The study sample consisted of 61 young male soccer players, members of two under 17 (U171 and U172) and two under 19 (U191 andU192) teams. U171 (n= 17, consists of ages: 15.1±0.6) and U191 (n=14, consists of ages 17.3±0.5 years) teams performed only soccer specific training whilst U172 (n= 18, consists of ages 15.0±0.4 years) and U192 (n=12 consists of ages 17.1±0.7 years) teams had two extra strength trainings per week. Anthropometric measurements were performed at the beginning and at the end of the 10-months session.
Results:
Lean body mass was increased whilst body fat decreased at the end of the study in all teams (p<0.001). No significant changes were found regarding endomorphic and ectomorphic outcome. Mesomorphic outcome was significantly increased only in U172 team (p<0.001).
Conclusions:
Our data supports that earlier interventions (between ages 15-17 years) in the training routine may be more effective in order to achieve anatomical and morphological characteristics most favorable for soccer.
Prolonged periods in microgravity (μG) environments result in deconditioning of numerous physiological systems, particularly muscle at molecular, single fiber, and whole muscle levels. This deconditioning leads to loss of strength and cardiorespiratory fitness. Loading muscle produces mechanical tension with resultant mechanotransduction initiating molecular signaling that stimulates adaptations in muscle. Exercise can reverse deconditioning resultant from phases of detraining, de-loading, or immobilization. On Earth, applications of loading using exercise models are common, as well as in μG settings as countermeasures to deconditioning. The primary modalities include, but are not limited to, aerobic training (or “cardio”) and resistance training, and have historically been dichotomized; the former primarily thought to improve cardiorespiratory fitness, and the latter primarily improving strength and muscle size. However, recent work questions this dichotomy, suggesting adaptations to loading through exercise are affected by intensity of effort independent of modality. Furthermore, similar adaptations may occur where sufficient intensity of effort is used. Traditional countermeasures for μG-induced deconditioning have focused upon engineering-based solutions to enable application of traditional models of exercise. Yet, contemporary developments in understanding of the applications, and subsequent adaptations, to exercise induced muscular loading in terrestrial settings have advanced such in recent years that it may be appropriate to revisit the evidence to inform how exercise can used in μG. With the planned decommissioning of the International Space Station as early as 2024 and future goals of manned moon and Mars missions, efficiency of resources must be prioritized. Engineering-based solutions to apply exercise modalities inevitably present issues relating to devices mass, size, energy use, heat production, and ultimately cost. It is necessary to identify exercise countermeasures to combat deconditioning while limiting these issues. As such, this brief narrative review considers recent developments in our understanding of skeletal muscle adaptation to loading through exercise from studies conducted in terrestrial settings, and their applications in μG environments. We consider the role of intensity of effort, comparisons of exercise modalities, the need for concurrent exercise approaches, and other issues often not considered in terrestrial exercise studies but are of concern in μG environments (i.e., O2 consumption, CO2 production, and energy costs of exercise).
Prolonged periods in microgravity (μG) environments result in deconditioning of numerous physiological systems, particularly muscle at molecular, single fiber, and whole muscle levels. This deconditioning leads to loss of strength and cardiorespiratory fitness. Loading muscle produces mechanical tension with resultant mechanotransduction initiating molecular signaling that stimulates adaptations in muscle. Exercise can reverse deconditioning resultant from phases of de-training, de-loading, or immobilization. On earth, applications of loading using exercise models are common, as well as in μG settings as countermeasures to deconditioning. The two primary modalities, aerobic training (or ‘cardio’), and resistance training, have historically been dichotomized; the former primarily thought to improve cardiorespiratory fitness, and the latter primarily improving strength and muscle size. However, recent work questions this dichotomy, suggesting adaptations to loading through exercise are affected by intensity of effort independent of modality. Furthermore, similar adaptations may occur where sufficient intensity of effort is used. Traditional countermeasures for μG induced deconditioning have focused upon engineering based solutions to enable application of traditional models of exercise. Yet, contemporary developments in understanding of the applications, and subsequent adaptations, to exercise induced muscular loading in terrestrial settings have advanced such in recent years that it may be appropriate to revisit the evidence to inform how exercise can used in μG. With the planned decommissioning of the International Space Station as early as 2024 and future goals of manned moon and Mars missions, efficiency of resources must be prioritized. Engineering based solutions to apply exercise modalities inevitably present issues relating to devices mass, size, energy use, heat production, and ultimately cost. It is necessary to identify exercise countermeasures to combat deconditioning whilst limiting these issues. As such, this brief narrative review considers recent developments in our understanding of skeletal muscle adaptation to loading through exercise from studies conducted in terrestrial settings, and their applications in μG environments. We consider the role of intensity of effort, comparisons of exercise modalities and the need for concurrent exercise approaches, and other issues often not considered in terrestrial exercise studies but are of concern in μG environments (i.e. O2 consumption, CO2 production, and energy costs of exercise).
Recent reports suggest that aerobic exercise may boost the hypertrophic response to short-term resistance training. This study explored the effects of an acute aerobic exercise bout on the transcriptional response to subsequent resistance exercise. Ten moderately trained men performed ~45 min cycling on one leg followed by 4x7 maximal knee extensions for each leg, 15 min later. Thus, one limb performed aerobic and resistance exercise (AE+RE), while the opposing leg did resistance exercise only (RE). Biopsies were obtained from m. vastus lateralis of each leg 3-h after the resistance exercise bout. Using DNA microarray, we analyzed differences (≥1.5-fold, FDR ≤10%) in gene expression profiles for the two modes of exercise. There were 176 genes up- (127) or down-regulated (49) by AE+RE compared with RE. Among the most significant differentially expressed genes were established markers for muscle growth and oxidative capacity, novel cytokines, transcription factors and microRNAs. The most enriched functional categories were those linked to carbohydrate metabolism and transcriptional regulation. Upstream analysis revealed that VEGF, CREB, TET2 and mTOR were regulators highly activated by AE+RE, whereas JnK, Nfκβ, MAPK and several miRNA's were inhibited. Thus, aerobic exercise alters the skeletal muscle transcriptional signature of resistance exercise to initiate important gene programs promoting both myofiber growth and improved oxidative capacity. These results provide novel insight into human muscle adaptations to diverse exercise modes and offer the very first genomic basis explaining how aerobic exercise may augment, rather than compromise muscle growth induced by resistance exercise.
This paper reviews the existing literature about muscle hypertrophy resulting from various types of training to document the significance of mechanical and metabolic stresses, and to challenge the conventional ideas of achieving hypertrophy that exclusively rely on highload resistance training. Low-load resistance training can induce comparable hypertrophy to that of high-load resistance training when each bout or set is performed until lifting failure. This is attributable to the greater exercise volume and metabolic stress achieved with low-load exercise at lifting failure, which, however, results in a prolonged exercise bout. Endurance exercises
(walking and cycling) at moderate intensity are also capable of eliciting muscle hypertrophy, but at much slower rates (months rather than weeks) in limited muscle or age groups. Blood flow restriction (BFR) in working muscles, however, accelerates the development of metabolic fatigue, alleviating the time consuming issue associated with low-load or endurance training. These alternative training methods, however, cannot completely replace conventional high-load resistance training, which provides superior strength gain as well as performance improvement even for trained individuals. The alternative approaches, therefore, may be considered for those who are less enthusiastic or under certain medical conditions, or who have limited or no access to proper equipment. However, people should be aware that low-load resistance training or endurance
training entails substantial effort and/or discomfort at lifting failure or with BFR. Understanding the advantages and disadvantages of each method will help in assigning the most suitable training program for each client’s goals and needs.
It is an undeniable fact that resistance training (RT) is a potent stimulus for muscle hypertrophy and strength gain, but it is less understood whether RT can increase maximal aerobic capacity (VO2max). The purpose of this brief review is to discuss whether or not RT enhances VO2max in young (20–40 years) and older subjects (>60 years). Only 3 of 17 studies involving young subjects have indicated significant increases in VO2max following RT, while six of nine studies in older subjects have reported significant improvements in VO2max following RT. There was a significant negative correlation between the initial VO2max and RT-induced change in VO2max. This result suggests that RT-induced increase in VO2max is dependent upon the subject’s initial VO2max. The RT-induced increase in VO2max may be elicited when their initial relative VO2max is lower than 25 ml/kg/min for older subjects and lower than 40 ml/kg/min for young subjects. Thus, RT can be expected to improve concurrently both muscular and cardiovascular fitnesses within a single mode of RT when young and old persons have initially low fitness levels.
It is known that ambulatory exercises such as brisk walking and jogging are potent stimuli for improving aerobic capacity, but it is less understood whether ambulatory exercise can increase leg muscle size and function. The purpose of this brief review is to discuss whether or not ambulatory exercise elicits leg muscle hypertrophy in older adults. Daily ambulatory activity with moderate (>3 metabolic equivalents [METs], which is defined as the ratio of the work metabolic rate to the resting metabolic rate) intensity estimated by accelerometer is positively correlated with lower body muscle size and function in older adults. Although there is conflicting data on the effects of short-term training, it is possible that relatively long periods of walking, jogging, or intermittent running for over half a year can increase leg muscle size among older adults. In addition, slow-walk training with a combination of leg muscle blood flow restriction elicits muscle hypertrophy only in the blood flow restricted leg muscles. Competitive marathon running and regular high intensity distance running in young and middle-aged adults may not produce leg muscle hypertrophy due to insufficient recovery from the damaging running bout, although there have been no studies that have investigated the effects of running on leg muscle morphology in older subjects. It is clear that skeletal muscle hypertrophy can occur independently of exercise mode and load.
Impairment in strength development has been demonstrated with combined strength and endurance training as compared with strength training alone. The purpose of this study was to examine the effects of combining conventional 3 d[middle dot]wk-1 strength and endurance training on the compatibility of improving both [latin capital V with dot above]O2peak and strength performance simultaneously. Sedentary adult males, randomly assigned to one of three groups (N = 10 each), completed 10 wk of training. A strength-only (S) group performed eight weight-training exercises (4 sets/exercise, 5-7 repetitions/set), an endurance-only (E) group performed continuous cycle exercise (50 min at 70% heart rate reserve), and a combined (C) group performed the same S and E exercise in a single session. S and C groups demonstrated similar increases (P < 0.0167) in 1RM squat (23% and 22%) and bench press (18% for both groups), in maximal isometric knee extension torque (12% and 7%), in maximal vertical jump (6% and 9%), and in fat-free mass (3% and 5%). E training did not induce changes in any of these variables. [latin capital V with dot above]O2peak (ml[middle dot]kg-1min-1) increased (P < 0.01) similarity in both E (18%) and C (16%) groups. Results indicate 3 d[middle dot]wk-1 combined training can induce substantial concurrent and compatible increases in [latin capital V with dot above]O2peak and strength performance.
(C)1995The American College of Sports Medicine
Exercise intolerance and undue fatigue are common complaints in patients with Charcot–Marie–Tooth (CMT) disease. Reduced physical ability is due directly to the disease, but it is also due to physical deconditioning. The aim of this study was to test whether 24 weeks of interval-training exercise (ITE) cycling can significantly improve physiological, neuromuscular, and functional capacities and alleviate fatigue in CMT patients. Eight CMT patients (4 CMT1A and 4 CMT2) participated in ITE for 3 nonconsecutive days per week. Cardiovascular fitness, muscle strength, fatigue resistance, and functional capacities were measured before and after 12 weeks of supervised hospital training and again after another 12 weeks of unsupervised home training. Training was well tolerated. There were significant improvements in cardiorespiratory capacities, isokinetic concentric strength, and functional ability measurements. All patients experienced an improvement in their self-reported visual analogic scale for fatigue and pain during training. However, there was no significant change in their isometric force production and indices of fatigue resistance after training. Although the improvement in exercise tolerance may be due in part to reversal of the deconditioning effect of their related sedentary lifestyle, this clinical trial suggests that ITE can benefit CMT patients especially in their functional performance and subjective perception of pain and fatigue. Moreover, the improvement observed at the end of the first supervised period ITE was maintained after the second unsupervised home period, although there was no further improvement in performance and tolerance. Muscle Nerve, 2008
To distinguish the respective potential of endurance and resistance training to increase the satellite cell pool, we investigated the effects of 14 weeks of concurrent lower body endurance and upper body resistance training (3 sessions/week) on vastus lateralis (VLat) and deltoid (Del) muscles of 10 active elderly men. NCAM+ satellite cells and myonuclear number were assessed in VLat and Del. After 14 weeks of training the NCAM+ satellite cell pool increased similarly (+38%) in both muscles, mainly in type II muscle fibers (P < 0.05). There was no significant change in myonuclear number or myonuclear domain in either muscle. Combining resistance training in the upper limbs with endurance training in the lower limbs is an efficient strategy to enhance the satellite cell pool in upper and lower body muscles in elderly subjects. Our results provide a practical reference for the determination of optimal exercise protocols to improve muscle function and regeneration in the elderly. Muscle Nerve, 2008
Fascicle angle (FA) is suggested to increase as a result of fiber hypertrophy and furthermore to serve as the explanatory link in the discrepancy in the relative adaptations in the anatomical cross-sectional area (CSA) and fiber CSA after resistance training (RT). In contrast to RT, the effects of endurance training on FA are unclear. The purpose of this study was therefore to investigate and compare the longitudinal effects of either progressive endurance training (END, n = 7) or RT (n = 7) in young untrained men on FA, anatomical CSA, and fiber CSA. Muscle morphological measures included the assessment of vastus lateralis FA obtained by ultrasonography and anatomical CSA by magnetic resonance imaging of the thigh and fiber CSA deduced from histochemical analyses of biopsy samples from m. vastus lateralis. Functional performance measures included VO2max and maximal voluntary contraction (MVC). The RT produced increases in FA by 23 ± 8% (p < 0.01), anatomical CSA of the knee extensor muscles by 9 ± 3% (p = 0.001), and fiber CSA by 19 ± 7% (p < 0.05). RT increased knee extensor MVC by 20 ± 5% (p < 0.001). END increased VO2max by 10 ± 2% but did not evoke changes in FA, anatomical CSA, or in fiber CSA. In conclusion, the morphological changes induced by 10 weeks of RT support that FA does indeed serve as the explanatory link in the observed discrepancy between the changes in anatomical and fiber CSA. Contrarily, 10 weeks of endurance training did not induce changes in FA, but the lack of morphological changes from END indirectly support the fact that fiber hypertrophy and FA are interrelated.
The primary objective of this investigation was to identify which components of endurance training (e.g., modality, duration, frequency) are detrimental to resistance training outcomes. A meta-analysis of 21 studies was performed with a total of 422 effect sizes (ESs). Criteria for the study included were (a) compare strength training alone to strength plus endurance training (concurrent) or to compare combinations of concurrent training; (b) the outcome measures include at least one measure of strength, power, or hypertrophy; and (c) the data necessary to calculate ESs must be included or available. The mean ES for hypertrophy for strength training was 1.23; for endurance training, it was 0.27; and for concurrent training, it was 0.85, with strength and concurrent training being significantly greater than endurance training only. The mean ES for strength development for strength training was 1.76; for endurance training, it was 0.78; and for concurrent training, it was 1.44. Strength and concurrent training was significantly greater than endurance training. The mean ES for power development for strength training only was 0.91; for endurance training, it was 0.11; and for concurrent training, it was 0.55. Significant differences were found between all the 3 groups. For moderator variables, resistance training concurrently with running, but not cycling, resulted in significant decrements in both hypertrophy and strength. Correlational analysis identified significant negative relationships between frequency (-0.26 to -0.35) and duration (-0.29 to -0.75) of endurance training for hypertrophy, strength, and power. Significant relationships (p < 0.05) between ES for decreased body fat and % maximal heart rate (r = -0.60) were also found. Our results indicate that interference effects of endurance training are a factor of the modality, frequency, and duration of the endurance training selected.
The purpose of this Position Stand is to provide guidance to professionals who counsel and prescribe individualized exercise to apparently healthy adults of all ages. These recommendations also may apply to adults with certain chronic diseases or disabilities, when appropriately evaluated and advised by a health professional. This document supersedes the 1998 American College of Sports Medicine (ACSM) Position Stand, "The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults." The scientific evidence demonstrating the beneficial effects of exercise is indisputable, and the benefits of exercise far outweigh the risks in most adults. A program of regular exercise that includes cardiorespiratory, resistance, flexibility, and neuromotor exercise training beyond activities of daily living to improve and maintain physical fitness and health is essential for most adults. The ACSM recommends that most adults engage in moderate-intensity cardiorespiratory exercise training for ≥30 min·d on ≥5 d·wk for a total of ≥150 min·wk, vigorous-intensity cardiorespiratory exercise training for ≥20 min·d on ≥3 d·wk (≥75 min·wk), or a combination of moderate- and vigorous-intensity exercise to achieve a total energy expenditure of ≥500-1000 MET·min·wk. On 2-3 d·wk, adults should also perform resistance exercises for each of the major muscle groups, and neuromotor exercise involving balance, agility, and coordination. Crucial to maintaining joint range of movement, completing a series of flexibility exercises for each the major muscle-tendon groups (a total of 60 s per exercise) on ≥2 d·wk is recommended. The exercise program should be modified according to an individual's habitual physical activity, physical function, health status, exercise responses, and stated goals. Adults who are unable or unwilling to meet the exercise targets outlined here still can benefit from engaging in amounts of exercise less than recommended. In addition to exercising regularly, there are health benefits in concurrently reducing total time engaged in sedentary pursuits and also by interspersing frequent, short bouts of standing and physical activity between periods of sedentary activity, even in physically active adults. Behaviorally based exercise interventions, the use of behavior change strategies, supervision by an experienced fitness instructor, and exercise that is pleasant and enjoyable can improve adoption and adherence to prescribed exercise programs. Educating adults about and screening for signs and symptoms of CHD and gradual progression of exercise intensity and volume may reduce the risks of exercise. Consultations with a medical professional and diagnostic exercise testing for CHD are useful when clinically indicated but are not recommended for universal screening to enhance the safety of exercise.
The aim of this work was the specification of the influence of the sprint and endurance training performed on the cycle ergometer on changes of muscle torque. Forty three students of the Academy of Physical Education in Warsaw took part in the study. They were divided into 4 groups and performing the cycle ergometer training consisting of 5 intermittent efforts (2 min break): S10 group- the sprint training (maximal efforts performed with the 10% body weight load); S5 group- the sprint training (maximal efforts conducted with 5% body weight load); W80 group – endurance training (the effort power equal 250 W, single – 3 min effort equal 45 kJ, the pedalling rate – 80 rpm, load 31,0 N appended on the cycle ergometer scale); W45 group – endurance training (the effort power equal 250 W, single – 3 min effort equal 45 kJ, the pedalling rate 45 rpm, load 55.0 N appended on the cycle ergometer scale). The four - week sprint training conducted on the cycle ergometer elicited the increase of the torque of the hip extensors and flexors in S10 and S5 group; extensors of the knee joint in S5 group and plantar flexors in S10 group. The four week endurance training carried out on the cycle ergometer caused the increase of the torque of hip extensors in groups W80 and W45, extensors of the knee joint and plantar flexors in group W45 as well the lowering of the torque of hip flexors in W80 and W45 group and the knee joint flexors in all groups. The significant increase of the sum of the 5 examined muscle groups torque was observed after the sprint training only. Some significant differences between the sprint and endurance training considered hip flexors and the sum of 5 examined muscle groups torque. The endurance training elicited the significant decrease of an hip flexors-to-extensors index value in groups W80 and W45 and of the knee joint in group W45.
The purpose of this investigation was to assess mixed-muscle fractional synthesis rate (FSR) and the expression of genes involved in skeletal muscle remodeling after aerobic exercise in the fasted and fed states. Eight recreationally active males (25 ± 1 yr; Vo(2 max): 52 ± 2 ml·kg(-1)·min(-1)) performed 60-min of cycle ergometry at 72 ± 1% Vo(2 max) on two occasions in a counter-balanced design. Subjects ingested a noncaloric placebo (EX-FAST) or a beverage containing (per kg body wt): 5 kcal, 0.83 g carbohydrate, 0.37 g protein, and 0.03 g fat (EX-FED) immediately and 1 h after exercise. FSR was assessed at rest and following exercise with the use of a l-[ring (2)H(5)]-phenylalanine infusion combined with muscle biopsies at 2 and 6 h postexercise. mRNA expression was assessed at 2 and 6 h postexercise via real-time RT-PCR. FSR was higher (P < 0.05) after exercise in both EX-FAST (0.112 ± 0.010%·h(-1)) and EX-FED (0.129 ± 0.014%·h(-1)) compared with rest (0.071 ± 0.005%·h(-1)). Feeding attenuated the mRNA expression (P < 0.05) of proteolytic factors MuRF-1 (6 h) and calpain-2 (2 and 6 h) postexercise but did not alter FOXO3A, calpain-1, caspase3, or myostatin mRNA expression compared with EX-FAST. Myogenic regulatory factor (MRF4) mRNA was also attenuated (P < 0.05) at 2 and 6 h postexercise in EX-FED compared with EX-FAST. These data demonstrate that a nonexhaustive bout of aerobic exercise stimulates skeletal muscle FSR in the fasted state and that feeding does not measurably enhance FSR between 2 and 6 h after aerobic exercise. Additionally, postexercise nutrient intake attenuates the expression of factors involved in the ubiquitin-proteosome and Ca(2+)-dependent protein degradation pathways. These data provide insight into the role of feeding on muscle protein metabolism during recovery from aerobic exercise.
We aimed to determine the effect of resistance exercise intensity (%1 repetition maximum-1RM) and volume on muscle protein synthesis, anabolic signaling, and myogenic gene expression.
Fifteen men (21+/-1 years; BMI=24.1+/-0.8 kg/m2) performed 4 sets of unilateral leg extension exercise at different exercise loads and/or volumes: 90% of repetition maximum (1RM) until volitional failure (90FAIL), 30% 1RM work-matched to 90%FAIL (30WM), or 30% 1RM performed until volitional failure (30FAIL). Infusion of [ring-13C6] phenylalanine with biopsies was used to measure rates of mixed (MIX), myofibrillar (MYO), and sarcoplasmic (SARC) protein synthesis at rest, and 4 h and 24 h after exercise. Exercise at 30WM induced a significant increase above rest in MIX (121%) and MYO (87%) protein synthesis at 4 h post-exercise and but at 24 h in the MIX only. The increase in the rate of protein synthesis in MIX and MYO at 4 h post-exercise with 90FAIL and 30FAIL was greater than 30WM, with no difference between these conditions; however, MYO remained elevated (199%) above rest at 24 h only in 30FAIL. There was a significant increase in AktSer473 at 24h in all conditions (P=0.023) and mTORSer2448 phosphorylation at 4 h post-exercise (P=0.025). Phosporylation of Erk1/2Tyr202/204, p70S6KThr389, and 4E-BP1Thr37/46 increased significantly (P<0.05) only in the 30FAIL condition at 4 h post-exercise, whereas, 4E-BP1Thr37/46 phosphorylation was greater 24 h after exercise than at rest in both 90FAIL (237%) and 30FAIL (312%) conditions. Pax7 mRNA expression increased at 24 h post-exercise (P=0.02) regardless of condition. The mRNA expression of MyoD and myogenin were consistently elevated in the 30FAIL condition.
These results suggest that low-load high volume resistance exercise is more effective in inducing acute muscle anabolism than high-load low volume or work matched resistance exercise modes.
The aim of the present study was to investigate the effects of concurrent strength and endurance training on neuromuscular and hormonal parameters in elderly men. 23 healthy men (65±4 years) were randomly assigned to 1 of 3 groups: concurrent (CG, n=8), strength (SG, n=8) or endurance group (EG, n=7). The programs consisted, of strength training, endurance training on a cycle ergometer or a combination of both in the same session 3 times per week over a duration of 12 weeks. Subjects were evaluated on parameters related to muscle strength, muscle activation and serum hormones. There were significant increases in lower-body strength in all groups (P<0.05), with higher increases in SG (67%) than CG (41%) and both were higher than EG (25%) (p<0.01). Only SG and CG increased upper-body strength (p<0.01), with no significant difference between the 2 groups. Furthermore, there were significant decreases in free testosterone in EG after training. Significant increases in isometric strength and maximal muscle activation (p<0.05) as well as decreases in the submaximal muscle activation to the same load, were only seen in SG (p<0.05). The present results suggest that the interference effect observed due to concurrent strength and endurance training could be related to impairment of neural adaptations.
Control of translation initiation in a tissue of an intact mammalian organism is a highly complex process requiring the continuous
integration of multiple positive and negative stimuli. For a tissue such as skeletal muscle, which has the capacity to undergo
dramatic changes in size and protein content, translation initiation contributes importantly to the regulation of global rates
of protein synthesis and is controlled by numerous stimuli, including those arising from nutrients and hormones in the circulating
blood, as well as from contraction-induced signaling within the tissue. Many of the pathways conveying signals generated by
these stimuli converge on mTORC1, a serine-threonine protein kinase that has been termed the nutrient and energy sensor of
the cell and that plays a prominent role in the regulation of cell growth. Control of translation initiation by mTORC1 is
mediated through phosphorylation of downstream targets that modulate the binding of mRNA to the 43 S preinitiation complex.
Control of translation initiation is also mediated through modulation of binding of initiator methionyl-tRNA to the 40 S ribosomal
subunit. Together, modulation of these two regulatory steps in translation initiation accounts in large part for changes in
protein synthesis in skeletal muscle produced by the integration of inputs from hormones, nutrients, and exercise.
We have recently shown that 12 weeks of progressive aerobic exercise training improves whole-muscle size and function in older women. The purpose of this investigation was to evaluate molecular markers that may be associated with muscle hypertrophy after aerobic training in aging skeletal muscle.
Muscle biopsies were obtained before and after 12 weeks of aerobic exercise training on a cycle ergometer in nine older women (70 ± 2 years) to determine basal levels of messenger RNA and protein content of select myogenic, proteolytic, and mitochondrial factors.
The training program increased (p < .05) aerobic capacity 30 ± 9%, whole-muscle cross-sectional area 11 ± 2%, and whole-muscle force production 29 ± 8%. Basal messenger RNA levels of FOXO3A, myostatin, HSP70, and MRF4 were lower (p < .05) after aerobic training. FOXO3A, FOXO3A phosphorylation, and HSP70 protein content were unaltered after training. Mitochondrial protein COX IV was elevated (p < .05) 33 ± 7% after aerobic training, whereas PGC-1α protein content was 20 ± 5% lower (p < .05).
These data suggest that reductions in FOXO3A and myostatin messenger RNA are potentially associated with exercise-induced muscle hypertrophy. Additionally, it appears that mitochondrial biogenesis can occur with aerobic training in older women independent of increased PGC-1α protein. Aerobic exercise training alters molecular factors related to the regulation of skeletal muscle, which supports the beneficial role of aerobic training for improving muscle health in older women.
The loss of lean muscle mass and muscle strength is a common problem in chronic heart failure (CHF) patients. Endurance training is efficient in improving patient exercise capacity. This study sought to evaluate the additional effects of strength training on muscle strength and body composition in chf patients participating in an interval training program.
Twenty consecutive, stable CHF patients participated in a rehabilitation program. Subjects were randomly assigned to aerobic (n = 10) or combined aerobic plus strength training group (n = 10). Aerobic group performed interval training on cycle ergometers. Strength training incorporated exercises for various muscle groups, including quadriceps, hamstrings, biceps brachii, and the deltoids. Both regimes were of the same duration. Body composition was evaluated by whole-body dual energy x-ray absorptiometry and quadriceps strength by the sum of the 2-repetition maximum (2-RM) test for each leg. Peak oxygen uptake (.VO(2peak)) and peak work load (W(peak)) as well as oxygen uptake (.VO(2AT)) and workload at anaerobic threshold (W(AT)) were evaluated by a symptom limited cardiopulmonary exercise testing.
Concerning leg lean mass, no significant within-subjects or between-groups changes were observed (P > .05). Both groups improved in 2-RM test (P < .05), while a significant difference was observed between groups (P < .05). .VO(2peak) and .VO(2AT) and W(peak) and W(AT) were equally improved between training groups (P < .05).
Combined aerobic interval and strength training induces a greater benefit than interval training alone on muscle strength in CHF patients. Adaptations other than hypertrophy, such as muscle fiber type alterations and/or neuromuscular adjustments, may account for these results.
This study examined the effect of aerobic training on leg strength, power, and muscle mass in previously sedentary, healthy older men (70-80 yr). Training consisted of 30-45 min of cycle ergometry at 50-70% maximal oxygen consumption (VO2max), 3 times weekly for 16 wk, then 4 wk detraining, or assignment to a nontraining control group (n = 12 both groups). Training increased leg strength, leg power, upper leg muscle mass, and VO2max above pretraining values (21%, 12%, 4%, and 15%, respectively; p < .05). However, all gains were lost after detraining, except for some gain in VO2max. This suggests that cycle ergometry is sufficient stimulus to improve neuromuscular function in older men, but gains are quickly lost with detraining. For the older population cycle ergometry provides the means to not only increase aerobic fitness but also increase leg strength and power and upper leg muscle mass. However, during periods of inactivity neuromuscular gains are quickly lost.
Background:
Aging is associated with loss in both muscle mass and the metabolic quality of skeletal muscle. A major part of these changes is associated with an age-related decrease in the level of physical activity and may be counteracted by endurance training (ET) and resistance training (RT).
Objective:
Since both muscle strength and aerobic power decrease with age, we investigated what form of training might be best for improvements in physical performance in the elderly. In detail, we wanted to know whether systematic ET can augment muscle strength and/or whether systematic RT can augment the aerobic power of healthy elderly adults.
Methods:
Forty-two volunteers (32 women, 10 men) were recruited for the study and randomized into three groups: 13 persons undertook a continuous 6-month ET program, 15 undertook a continuous 6-month RT program and 14 served as a control group. All persons performed a cycling test to measure aerobic power (VO(2max)) and maximum workload (W(max)) before and after the training period. Maximum strength was determined from one repetition maximum (1-RM).
Results:
After 6 months of RT, maximum strength increased by an average of 15% for leg press (P < 0.01), 25% for bench press (P < 0.01) and 30% for bench pull (P < 0.001); ET showed no effect on maximum strength except for the 1-RM in bench pull. Aerobic power improved by 6% in the ET group and by 2.5% in the RT group, neither of which was significant. Maximum workload improved significantly by 31% in the ET group (P < 0.001) and by 6% in the RT group (P = 0.05). ET resulted in a significant 5.3% reduction of body fat (P < 0.05), whereas only RT increased lean body mass by 1.0 +/- 0.5 kg.
Conclusion:
RT leads to a genuine increase in lean body mass and muscle strength in healthy elderly adults and is therefore the best method for treatment of amyotrophia. ET appears to be the most efficacious training mode for maintaining and improving maximum aerobic power in the elderly and should be viewed as a complement to RT. The loading intensity to promote hypertrophy should approach 60-80% of 1-RM with an exercise volume ranging from 3 to 6 sets per muscle group per week of 10-15 repetitions per exercise. ET should be performed on two days per week controlled by a heart rate according to 60% of VO(2max) and an exercise volume ranging from 30 to 60 minutes per week.
Haemodialysis patients (HDP) with anaemia display impaired plasma K(+) regulation during exercise and poor exercise performance. Epoetin treatment and exercise training improve exercise performance in HDP, but whether this is associated with improved K(+) regulation is unknown.
Six HDP with near-normal [Hb] were tested for aerobic power ( ) and plasma [K(+)] during incremental exercise; quadriceps muscle strength (peak torque, PT) from 0 to 360 degrees s(-1) and fatiguability (decline in strength during thirty contractions). Tests were conducted at baseline, after 6 weeks of normal activity (pre-train) and following 6 weeks cycle training (post-train). Six healthy untrained controls (CON) matched for age, sex, mass and height were tested at baseline.
In HDP at baseline, and PT from 0 to 360 degrees s(-1) were respectively reduced by 37% and 27-42%, compared to CON (P < 0.05). Plasma [K(+)], the rise in [K(+)] (Delta[K(+)]) and the Delta[K(+)] relative to total work done (Delta[K(+)] work(-1) ratio) during incremental exercise were all higher in HDP at baseline compared to CON (P < 0.05). Exercise training increased time to fatigue by 12% (P < 0.05) but did not improve K(+) regulation or . An inverse correlation was found between the Delta[K(+)] work(-1) ratio and for pooled CON and HDP data.
In HDP treated with epoetin, poor exercise performance was related to impaired extrarenal K(+) regulation, whilst training improved exercise performance but not K(+) regulation. Thus, although impaired extrarenal K(+) regulation may contribute to poor exercise performance in HDP, exercise performance can still improve with training despite unchanged K(+) regulation.
Long-term adaptation to resistance training is probably due to the cumulative molecular effects of each exercise session. Therefore, we studied in female Wistar rats the molecular effects of a chronic resistance training regimen (3 months) leading to skeletal muscle hypertrophy in the plantaris muscle. Our results demonstrated that muscle proteolytic genes MuRF-1 and Atrogin-1 were significantly decreased in the exercised group measured 24 h after the last resistance exercise session (41.64 and 61.19%, respectively; P < 0.05). Nonetheless, when measured at the same time point, 4EBP-1, GSK-3beta and eIF2Bepsilon mRNA levels and Akt, GSK-3beta and p70S6K protein levels (regulators of translation initiation) were not modified. Such data suggests that if gene transcription constitutes a control point in the protein synthesis pathway this regulation probably occurs in early adaptation periods or during extreme situations leading to skeletal muscle remodeling. However, proteolytic gene expression is modified even after a prolonged resistance training regimen leading to moderate skeletal muscle hypertrophy.
In this review we discuss current findings in the human skeletal muscle literature describing the acute influence of nutrients (leucine-enriched essential amino acids in particular) and resistance exercise on muscle protein synthesis and mammalian target of rapamycin complex 1 (mTORC1) signaling. We show that essential amino acids and an acute bout of resistance exercise independently stimulate human skeletal muscle protein synthesis. It also appears that ingestion of essential amino acids following resistance exercise leads to an even larger increase in the rate of muscle protein synthesis compared with the independent effects of nutrients or muscle contraction. Until recently the cellular mechanisms responsible for controlling the rate of muscle protein synthesis in humans were unknown. In this review, we highlight new studies in humans that have clearly shown the mTORC1 signaling pathway is playing an important regulatory role in controlling muscle protein synthesis in response to nutrients and/or muscle contraction. We propose that essential amino acid ingestion shortly following a bout of resistance exercise is beneficial in promoting skeletal muscle growth and may be useful in counteracting muscle wasting in a variety of conditions such as aging, cancer cachexia, physical inactivity, and perhaps during rehabilitation following trauma or surgery.
A common belief among many clinicians and trainers is that intensive simultaneous training for muscle strength and cardiovascular endurance is counterproductive. To test this premise, 14 healthy, untrained men trained four days per week for 20 weeks on a bicycle ergometer for endurance (END Group, n = 4), on an isokinetic device for increased torque production (ITP Group, n = 5), or on both devices (COMBO Group, n = 5). The ITP and COMBO groups had equal torque gains throughout the study (234 +/- 45 and 232 +/- 23 N.m, respectively). After 11 weeks, both END and COMBO groups had similar gains in maximal oxygen consumption (VO2max) (in milliliters per kilogram of body weight per minute). During the last half of the study, however, the END Group had a significant gain in VO2max (p less than .05) of 4.7 +/- 1.2 mL.kg-1.min-1, whereas the COMBO Group had a nonsignificant gain (p greater than .05) of 1.8 +/- 0.6 mL.kg-1.min-1. In harmony with this finding, the END Group showed a significant increase (p less than .05) in citrate synthase activity (15.5 +/- 7.9 mumol.g-1.min-1), whereas the COMBO Group had no significant increase. The authors concluded that simultaneous training may inhibit the normal adaptation to either training program when performed alone. The extent of the interference probably depends on the nature and intensity of the individual training program. [Nelson AG, Arnall DA, Loy SF, et al: Consequences of combining strength and endurance training regimens.
The response of muscle fiber type proportions and fiber areas to 15 weeks of strenuous high-intensity intermittent training was investigated in twenty-four carefully ascertained sedentary (14 women and 10 men) and 10 control (4 women and 6 men) subjects. The supervised training program consisted mainly of series of supramaximal exercise lasting 15 s to 90 s on a cycle ergometer. Proportions of muscle fiber type and areas of the fibers were determined from a biopsy of the vastus lateralis before and after the training program. No significant change was observed for any of the histochemical characteristics in the control group. Training significantly increased the proportion of type I and decreased type IIb fibers, the proportion of type IIa remained unchanged. Areas of type I and IIb fibers increased significantly with training. These results suggest that high-intensity intermittent training in humans may alter the proportion of type I and the area of type I and IIb fibers and in consequence that fiber type composition in human vastus lateralis muscle is not determined solely by genetic factors.
Eleven men sprint trained two to three times per week for 6 wk to investigate possible exercise-induced slow-to-fast fiber type conversions. Six individuals served as controls. Both groups were tested at the beginning and end of the study to determine anaerobic performance and maximal oxygen consumption. In addition, pre- and postbiopsies were extracted from the vastus lateralis muscle and were analyzed for fiber type composition, cross-sectional area, and myosin heavy chain (MHC) content. No significant changes were found in anaerobic or aerobic performance variables for either group. Although a trend was found for a decrease in the percentage of type IIb fibers, high-intensity sprint cycle training caused no significant changes in the fiber type distribution or cross-sectional area. However, the training protocol did result in a significant decrease in MHC IIb with a concomitant increase in MHC IIa for the training men. These data appear to support previous investigations that have suggested exercise-induced adaptations within the fast fiber population (IIb-->IIa) after various types of training (endurance and strength).
To compare the effects of the 16-wk training period (2 d.wk(-1)) of resistance training alone (S), endurance training alone (E), or combined resistance (once weekly) and endurance (once weekly) training (SE) on muscle mass, maximal strength and power of the leg and arm extensor muscles, and maximal workload (Wmax) by using a incremental cycling test in older men.
Thirty-one healthy men (65-74 yr) were divided into three treatment groups to train 2x wk(-1) for 16 wk: S (N = 10), E (N = 11), or SE (N = 10; 1x wk(-1) S + 1x wk(-1) E). The subjects were tested at 8-wk intervals (i.e., weeks 8 and 16).
There were no significant differences between S- and SE-induced muscle hypertrophy (11% and 11%) and maximal strength (41% and 38%) gains of the legs as well as between E- and SE-induced Wmax (28% and 23%) gains. The increase in arm strength in S (36%) was greater than that recorded in SE (22%) and greater than that recorded in E (0%).
Prolonged combined resistance and endurance training in older men seemed to lead to similar gains in muscle mass, maximal strength, and power of the legs as resistance training alone and to similar gains in maximal peak power output measured in an incremental cycling test as endurance training alone. These findings may have an effect on how resistance exercise is prescribed to older adults.
To learn the mechanisms underlying resistance exercise-induced muscle hypertrophy, recent studies on muscle protein metabolism and myogenic progenitor cells were reviewed. Numerous studies have suggested that activation of the translation process plays a major role in a resistance exercise-induced increase in muscle protein synthesis, and also in muscle hypertrophy after a prolonged period of training. Among regulators of the translational activity, the mTORC1 signaling pathway has been shown to be important, although the relation between its upstream regulation and exercise regimen remains unclear. In addition, the muscle satellite cells play a part, even if not indispensable, in exercise-induced muscle hypertrophy, by supplying muscle fibers with new myonuclei. Middle to high exercise intensity has been regarded as essential for gaining muscle mass, because it causes the recruitment of large motor units with fast, type II muscle fibers, which are readily hypertrophied through activation of mTORC1 signaling. However, several studies have shown that low-intensity resistance exercises with either large exercise volume or prolonged contraction time effectively activate protein synthesis and induce muscle hypertrophy. These findings suggest that various strategies are possible in exercise regimens, and exercise intensity is not necessarily a primary factor for gaining muscular size.
Protein synthesis is a highly energy-consuming process that must be tightly regulated. Signal transduction cascades respond to extracellular and intracellular cues to phosphorylate proteins involved in ribosomal biogenesis and translation initiation and elongation. These phosphorylation events regulate the timing and rate of translation of both specific and total mRNAs. Alterations in this regulation can result in dysfunction and disease. While many signaling pathways intersect to control protein synthesis, the mTOR and MAPK pathways appear to be key players. This chapter briefly reviews the mTOR and MAPK pathways and then focuses on individual phosphorylation events that directly control ribosome biogenesis and translation.