No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Concurrent exercise training: Do opposites distract?
The Journal of Physiology
Abstract
Specificity is a core principle of exercise training to promote the desired adaptations for maximising athletic performance. The principle of specificity of adaptation is underpinned by the volume, intensity, frequency and mode of contractile activity and is most evident when contrasting the divergent phenotypes that result after undertaking either prolonged endurance or resistance training. The molecular profiles that generate the adaptive response to different exercise modes have undergone intense scientific scrutiny. Given divergent exercise induces similar signalling and gene expression profiles in skeletal muscle of untrained or recreationally active individuals, what is currently unclear is how the specificity of the molecular response is modified by prior training history. The time-course of adaptation and when ‘phenotype specificity’ takes place has important implications for exercise prescription. This context is essential when attempting to concomitantly develop resistance to fatigue (through endurance-based exercise) and increased muscle mass (through resistance-based exercise), typically termed ‘concurrent training.’ Chronic training studies provide robust evidence that endurance exercise can attenuate muscle hypertrophy and strength but the mechanistic underpinning of this ‘interference’ effect with concurrent training is unknown. Moreover, despite the potential for several key regulators of muscle metabolism to explain an incompatibility in adaptation between endurance and resistance exercise, it now seems likely that multiple integrated, rather than isolated, effectors or processes generate the interference effect. Here we review studies of the molecular responses in skeletal muscle and evidence for the interference effect with concurrent training within the context of the specificity of training adaptation. This article is protected by copyright. All rights reserved
... Nonetheless, it appears that performing strength training (ST) and endurance training (ET) concurrently can interfere with long-term adaptations compared to when they are performed alone [8][9][10][11][12][13][14] . Notably, when one training type is performed subsequently to the other training, acute local or systemic fatigue would interfere with later performance 15 . ...
... The interference effect occasionally observed after CT in team sports is often attributed to competing molecular pathways activated by the different training modalities (i.e., strength and endurance training). The activation of the adenosine monophosphateactivated protein kinase (AMPK) enzyme following ET may hinder signalling to the protein-synthesis machinery by suppressing the activity of the mammalian target of rapamycin (mTOR) and its downstream targets 6,8,14,[61][62][63] . The concurrent activation of these pathways can lead to attenuated gains in power, strength, and muscle hypertrophy. ...
... However, this may not fully explain the phenomenon as a whole, as the foundations of CT models based on animal studies and research involving humans show broadly varied responses at the molecular level following CT 6,8,62,[64][65] . Therefore, there may be other possible mediators that could elucidate the observed interference. ...
... It has been suggested that previous endurance training may compromise subsequent resistance exercise quality and vice versa, due to residual fatigue and/or reduced substrate availability (e.g., depleted glycogen levels resulting in increased skeletal muscle protein breakdown) [14][15][16]. Moreover, there is a body of evidence suggesting that adaptations to endurance and resistance training may interfere with each other under certain circumstances [14,15,[17][18][19]. This so-called interference effect was first observed in a pioneering study by Hickson [20], who found that simultaneous endurance and resistance training resulted in a reduced capacity to develop muscle strength when compared to resistance training alone in recreationally active subjects. ...
... This so-called interference effect was first observed in a pioneering study by Hickson [20], who found that simultaneous endurance and resistance training resulted in a reduced capacity to develop muscle strength when compared to resistance training alone in recreationally active subjects. Although this finding was not always confirmed in follow-up studies, multiple investigations showed similar results, indicating that particularly muscle strength development and hypertrophy can potentially be diminished by concurrent training [14,15,[17][18][19], most likely due to antagonistic molecular mechanisms underlying adaptations to both types of exercise [14,15,17]. Additionally, it has been demonstrated that untrained individuals can experience lower VO 2max improvements with concurrent versus endurance training only [21]. ...
... This so-called interference effect was first observed in a pioneering study by Hickson [20], who found that simultaneous endurance and resistance training resulted in a reduced capacity to develop muscle strength when compared to resistance training alone in recreationally active subjects. Although this finding was not always confirmed in follow-up studies, multiple investigations showed similar results, indicating that particularly muscle strength development and hypertrophy can potentially be diminished by concurrent training [14,15,[17][18][19], most likely due to antagonistic molecular mechanisms underlying adaptations to both types of exercise [14,15,17]. Additionally, it has been demonstrated that untrained individuals can experience lower VO 2max improvements with concurrent versus endurance training only [21]. ...
Combined endurance and resistance training, also known as “concurrent training”, is a common practice in exercise routines. While concurrent training offers the benefit of targeting both cardiovascular and muscular fitness, it imposes greater physiological demands on the body compared to performing each modality in isolation. Increased protein consumption has been suggested to support adaptations to concurrent training. However, the impact of protein supplementation on responses to low-volume concurrent training is still unclear. Forty-four untrained, healthy individuals (27 ± 6 years) performed two sessions/week of low-volume high-intensity interval training on cycle ergometers followed by five machine-based resistance training exercises for 8 weeks. Volunteers randomly received (double-blinded) 40 g of whey-based protein (PRO group) or an isocaloric placebo (maltodextrin, PLA group) after each session. Maximal oxygen consumption (VO2max) and overall fitness scores (computed from volunteers’ VO2max and one-repetition maximum scores, 1-RM) significantly increased in both groups. The PRO group showed significantly improved 1-RM in all major muscle groups, while the PLA group only improved 1-RM in chest and upper back muscles. Improvements in 1-RM in leg muscles were significantly greater in the PRO group versus the PLA group. In conclusion, our results indicate that adaptations to low-volume concurrent training, particularly leg muscle strength, can be improved with targeted post-exercise protein supplementation in untrained healthy individuals.
... In the existing literature, numerous studies have been noticed that exhibit similar experimental designs [47][48][49][50][51][52]. For instance, Sporer and Wenger [48] conducted a study demonstrating that the type and intensity of aerobic training can influence subsequent performance in a strength training session, depending on the recovery period. ...
... One possible explanation is related to the physiological adaptations that occur in response to aerobic exercise, such as increased Adenosine Monophosphate (AMP) activated protein kinase (AMPK) activity and the subsequent inhibition of protein synthesis pathways that are crucial for muscle hypertrophy. Additionally, aerobic exercise can lead to temporary fatigue and depletion of energy stores, which can impair subsequent strength training performance [51,52]. In summary, within the scholarly literature, upon a comprehensive evaluation of the referenced studies [15,[49][50][51][52], it becomes evident that aerobic exercises executed with varying rest intervals elicit disparate effects on a range of physical performance attributes. ...
... Additionally, aerobic exercise can lead to temporary fatigue and depletion of energy stores, which can impair subsequent strength training performance [51,52]. In summary, within the scholarly literature, upon a comprehensive evaluation of the referenced studies [15,[49][50][51][52], it becomes evident that aerobic exercises executed with varying rest intervals elicit disparate effects on a range of physical performance attributes. However, our research concluded that HIIT exercises with long and short rest intervals have no effect on strength. ...
The aim of this study was to evaluate the effect of 8 weeks of short and long rest running-based high-intensity training (HIIT) on body composition, isokinetic strength, and maximal oxygen uptake (VO 2max). Nineteen physically active men were recruited to voluntarily participate in the study. The participants were grouped using the closed-envelope randomized method as HIIT with a short rest (HIITS, n = 9; age: 19.60 ± 1.34 years) and HIIT with a long rest (HIITL, n = 10; age: 19.77 ± 0.97). Pre and post the 8-week running-based HIIT program, body mass index and body fat % were measured and all subjects performed isokinetic strength tests to determine their hamstring (H)/quadriceps (Q) peak torque ratio and the peak power and peak work for their H and Q muscles. The participants also underwent a graded exercise test to determine their VO 2max. Statistical analysis performed with One-Way Variance Analysis and Bonferroni correction post hoc tests. As a result of the study, there were no significant differences between the pre-and post-training isokinetic strength parameters for the H and Q of HIITL and HIITS at velocities of 60 and 240 • s −1. The VO 2max did not change for HIITS training but the VO 2max increased (p < 0.05) for HIITL training. In conclusion, that HIITL and HIITS programs for 8 weeks did not change the relative and absolute strength, force production and the VO 2max , but the VO 2max increased (p < 0.05) for HIITL training. Keywords Peak torque; Peak power; Peak work; VO 2max ; H/Q ratio
... In the existing literature, numerous studies have been noticed that exhibit similar experimental designs [47][48][49][50][51][52]. For instance, Sporer and Wenger [48] conducted a study demonstrating that the type and intensity of aerobic training can influence subsequent performance in a strength training session, depending on the recovery period. ...
... One possible explanation is related to the physiological adaptations that occur in response to aerobic exercise, such as increased Adenosine Monophosphate (AMP) activated protein kinase (AMPK) activity and the subsequent inhibition of protein synthesis pathways that are crucial for muscle hypertrophy. Additionally, aerobic exercise can lead to temporary fatigue and depletion of energy stores, which can impair subsequent strength training performance [51,52]. In summary, within the scholarly literature, upon a comprehensive evaluation of the referenced studies [15,[49][50][51][52], it becomes evident that aerobic exercises executed with varying rest intervals elicit disparate effects on a range of physical performance attributes. ...
... Additionally, aerobic exercise can lead to temporary fatigue and depletion of energy stores, which can impair subsequent strength training performance [51,52]. In summary, within the scholarly literature, upon a comprehensive evaluation of the referenced studies [15,[49][50][51][52], it becomes evident that aerobic exercises executed with varying rest intervals elicit disparate effects on a range of physical performance attributes. However, our research concluded that HIIT exercises with long and short rest intervals have no effect on strength. ...
The aim of this study was to evaluate the effect of 8 weeks of short and long rest running-based high-intensity training (HIIT) on body composition, isokinetic strength, and maximal oxygen uptake (VO2max). Nineteen physically active men were recruited to voluntarily participate in the study. The participants were grouped using the closed-envelope randomized method as HIIT with a short rest (HIITS, n = 9; age: 19.60 ± 1.34 years) and HIIT with a long rest (HIITL, n = 10; age: 19.77 ± 0.97). Pre and post the 8-week running-based HIIT program, body mass index and body fat % were measured and all subjects performed isokinetic strength tests to determine their hamstring (H)/quadriceps (Q) peak torque ratio and the peak power and peak work for their H and Q muscles. The participants also underwent a graded exercise test to determine their VO2max. Statistical analysis performed with One-Way Variance Analysis and Bonferroni correction post hoc tests. As a result of the study, there were no significant differences between the pre- and post-training isokinetic strength parameters for the H and Q of HIITL and HIITS at velocities of 60 and 240◦s−1. The VO2max did not change for HIITS training but the VO2max increased (p < 0.05) for HIITL training. In conclusion, that HIITL and HIITS programs for 8 weeks did not change the relative and absolute strength, force production and the VO2max, but the VO2max increased (p < 0.05) for HIITL training.
... The effectiveness of different CT modalities on measures of physical fitness has been extensively studied in the past and produced conflicting results [11,12]. Some studies suggest that the concurrent training of strength and aerobic capacity may interfere with physiological adaptations, i.e., preventing the development of the full adaptive potential [13,14]. This interference effect is often attributed to incompatible intracellular signaling mechanisms between the mechanistic target of rapamycin (mTOR) as the main mediator for strength and hypertrophy training adaptations and AMP-activated protein kinase (AMPK) for mitochondrial biogenesis following endurance training [5,13]. ...
... Some studies suggest that the concurrent training of strength and aerobic capacity may interfere with physiological adaptations, i.e., preventing the development of the full adaptive potential [13,14]. This interference effect is often attributed to incompatible intracellular signaling mechanisms between the mechanistic target of rapamycin (mTOR) as the main mediator for strength and hypertrophy training adaptations and AMP-activated protein kinase (AMPK) for mitochondrial biogenesis following endurance training [5,13]. This phenomenon has been observed in various populations, including prepubescent children aged 10.9 ± 0.5 years [15,16], young male adults aged 23 ± 0.6 years [17], untrained middle-aged males aged 42.0 ± 2.0 years [5,18], and recreationally trained male endurance runners aged 23.0 ± 2.0 years [19]. ...
... This is likely a result of higher adaptive potential for morphological responses such as muscle hypertrophy due to increased levels of androgenic hormones (i.e., testosterone) in pubescent and postpubescent youth [11]. Higher potential for morphological adaptations also implicate a greater chance of experiencing interference effects induced by the mTOR and AMPK pathway mechanisms [5,13]. ...
Background
Various physical fitness qualities such as muscle strength, speed and endurance are related to soccer performance. Accordingly, the combination of strength and endurance training (i.e., concurrent training [CT]) is an often-encountered training regimen in soccer. Less is known about the effects of CT sequencing on performance in young soccer players. The aim of this study was to assess the sequencing effects of strength and intermittent endurance training applied within the same training session (intrasession) on measures of physical fitness and soccer performance in young soccer players.
Methods
Fifty male adolescent soccer players volunteered to participate in this study which was conducted in the Netherlands in 2019. Players were randomly assigned to a strength-endurance (SE) or an endurance-strength (ES) group in matched pairs based on their countermovement jump (CMJ) performance at baseline. Both groups completed a 12-weeks in-season training program with two weekly CT sessions. Training sessions consisted of 15 min plyometric exercises and 15 min soccer-specific intermittent endurance training. Both groups performed the same training volumes and the only difference between the groups was the CT intrasession sequencing scheme (SE vs. ES). Pre and post intervention, proxies of muscle power (CMJ, squat jump [SJ]), linear sprint speed (30-m sprint test), agility (Illinois test with / without ball), and soccer performance (ball kicking velocity) were tested.
Results
Data from 38 players aged 14.8 ± 1.0 years (body height 172.9 ± 8.1 cm, body mass: 57.0 ± 7.2 kg, soccer experience: 8.8 ± 2.8 years, age from peak-height-velocity [PHV]: +1.2 ± 1.0 years) were included. Significant main time effects were found for CMJ (p = 0.002, d = 0.55), SJ (p = 0.004, d = 0.51), the Illinois agility test with ball (p = 0.016, d = 0.51), and ball kicking velocity (p = 0.016, d = 0.51). Significant group-by-time interactions were observed for 30-m linear sprint speed (p < 0.001, d = 0.76) with ES showing greater improvements (p = 0.006, d = 0.85, Δ-5%).
Conclusions
Both CT-sequencing types improved performance in the tests administered. The intrasession CT sequencing (SE vs. ES) appears not to have a major impact on physical fitness adaptations, except for linear sprint speed which was in favor of ES.
... Because of the high cardiovascular and metabolic demands of fire suppression tasks (35,(69)(70)(71), the National Fire Protection Association (NFPA) recommends a minimal cardiovascular fitness level of 42 mL$kg 21 $minute 21 (12 METs). Considering specificity, it is likely that RT will generally stimulate increases in hypertrophy, strength, and power, whereas AT will stimulate increases in mitochondrial density, cardiac output, and maximal oxygen consumption (i.e., increased METs) (4,11,64,76). With this information in mind, it is prudent for a fire academy training program to supplement RT with AT such as cycling, jogging, or rowing, because the latter modalities would help improve cardiovascular fitness (4,11,64,76). ...
... Considering specificity, it is likely that RT will generally stimulate increases in hypertrophy, strength, and power, whereas AT will stimulate increases in mitochondrial density, cardiac output, and maximal oxygen consumption (i.e., increased METs) (4,11,64,76). With this information in mind, it is prudent for a fire academy training program to supplement RT with AT such as cycling, jogging, or rowing, because the latter modalities would help improve cardiovascular fitness (4,11,64,76). Concurrent training (CT), commonly defined as including AT and RT within the same training day, week, month, or block, has been thoroughly studied in the exercise science literature (4,11,22,33,55,64,76). Early meta-analytical data indicated that AT would negatively affect common adaptations to RT, such as hypertrophy, strength, and power (76). ...
... With this information in mind, it is prudent for a fire academy training program to supplement RT with AT such as cycling, jogging, or rowing, because the latter modalities would help improve cardiovascular fitness (4,11,64,76). Concurrent training (CT), commonly defined as including AT and RT within the same training day, week, month, or block, has been thoroughly studied in the exercise science literature (4,11,22,33,55,64,76). Early meta-analytical data indicated that AT would negatively affect common adaptations to RT, such as hypertrophy, strength, and power (76). ...
Firefighting is a physically demanding occupation that requires individuals to possess considerably high levels of muscular endurance, strength, power, and aerobic fitness. Under most circumstances, a firefighter's career begins with a training academy during which they learn essential job tasks (e.g., victim rescue) while performing a variety of exercise programs. Based on the current literature, several forms of resistance, aerobic, circuit, concurrent, and functional training positively affect the physical fitness and occupational performance of firefighter recruits. Because many fire departments have limited gym access, it is most practical for training academies to adopt exercise programs that can be completed with their academy's specific equipment and facility confines. Luckily, the research discussed within this paper demonstrates that effective training can be performed with minimal and maximal facility/equipment access. Regarding future studies, it would be interesting for researchers to compare the effects of minimal-equipment and maximal-equipment programs and apply training plans that combine these 2 extremes. Moreover, to accommodate the execution and learning of occupational tasks, researchers should explore periodizing training plans around the current physical demands of the academy while applying minimum effective training doses.
... It has, for example, been demonstrated that increases in maximal strength and fast-force production [7,8] (i.e., the rate of force development or the ability of the neuromuscular system to generate force rapidly [9]) as well as muscle hypertrophy [10] may be blunted when strength and endurance are performed concurrently, although this is not always the case [11,12]. Where evidence for "interference" of endurance training on strength, fast-force production, and hypertrophy exists in male participants [10][11][12], mechanisms related to acute and chronic neuromuscular fatigue, molecular pathways, and the energetic demands of concurrent training are suggested to be responsible [13]. While these mechanisms may also contribute to "interference" in females, evidence is sparse. ...
... Reviews have evaluated the effect of endurance training on muscle hypertrophy [10][11][12], while also exploring topics such as detraining [30]. Several reviews have addressed additional mechanisms explaining the "interference effect" including signaling pathways [13,[31][32][33][34][35][36], myosin heavy chain content [36], and fiber type distribution [37]. Models for examination of the "interference effect" have been presented, while "acute" and "chronic" hypotheses behind the "interference effect" [38] have been proposed. ...
... Strength training included primarily hypertrophic and heavy/maximal intensities (as described by study authors), including combinations of, e.g., maximal and explosive strength training. The quality of the studies was rated as moderate (10)(11)(12)(13). In two studies, concurrent strength and endurance training were compared to strength training only, endurance training only, and a control group. ...
Background
Both strength and endurance training are included in global exercise recommendations and are the main components of training programs for competitive sports. While an abundance of research has been published regarding concurrent strength and endurance training, only a small portion of this research has been conducted in females or has addressed their unique physiological circumstances (e.g., hormonal profiles related to menstrual cycle phase, menstrual dysfunction, and hormonal contraceptive use), which may influence training responses and adaptations.
Objective
The aim was to complete a systematic review of the scientific literature regarding training adaptations following concurrent strength and endurance training in apparently healthy adult females.
Methods
A systematic electronic search for articles was performed in July 2021 and again in December 2022 using PubMed and Medline. This review followed, where applicable, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of the included studies was assessed using a modified Downs and Black checklist. Inclusion criteria were (1) fully published peer-reviewed publications; (2) study published in English; (3) participants were healthy normal weight or overweight females of reproductive age (mean age between > 18 and < 50) or presented as a group (n > 5) in studies including both females and males and where female results were reported separately; (4) participants were randomly assigned to intervention groups, when warranted, and the study included measures of maximal strength and endurance performance; and (5) the duration of the intervention was ≥ 8 weeks to ensure a meaningful training duration.
Results
Fourteen studies met the inclusion criteria (seven combined strength training with running, four with cycling, and three with rowing or cross-country skiing). These studies indicated that concurrent strength and endurance training generally increases parameters associated with strength and endurance performance in female participants, while several other health benefits such as, e.g., improved body composition and blood lipid profile were reported in individual studies. The presence of an “interference effect” in females could not be assessed from the included studies as this was not the focus of any included research and single-mode training groups were not always included alongside concurrent training groups. Importantly, the influence of concurrent training on fast-force production was limited, while the unique circumstances affecting females were not considered/reported in most studies. Overall study quality was low to moderate.
Conclusion
Concurrent strength and endurance training appears to be beneficial in increasing strength and endurance capacity in females; however, multiple research paradigms must be explored to better understand the influence of concurrent training modalities in females. Future research should explore the influence of concurrent strength and endurance training on fast-force production, the possible presence of an “interference effect” in athletic populations, and the influence of unique circumstances, such as hormone profile, on training responses and adaptations.
... This is supported by research suggesting that aerobic exercise activates catabolic pathways, while anaerobic exercise stimulates anabolic pathways [10]. There are differences in the intracellular signaling response between the two types of exercises [11,12]. The findings led to the hypothesis of the AMP-activated protein kinase pathway (AMPK)phosphatidylinositol 3-kinase (AKT) switch, suggesting that there is a discrepancy in the signaling responses produced by anaerobic and aerobic exercises, which may not complement each other to optimize muscular adaptations. ...
... The findings led to the hypothesis of the AMP-activated protein kinase pathway (AMPK)phosphatidylinositol 3-kinase (AKT) switch, suggesting that there is a discrepancy in the signaling responses produced by anaerobic and aerobic exercises, which may not complement each other to optimize muscular adaptations. AMPK signaling is for the catabolic pathway and is often associated with aerobic endurance exercises, while AKT signaling is for the anabolic pathway and is often associated with anaerobic or resistance training exercises [12]. However, this theory can be overly simplified and leads to misinterpretation. ...
... Multiple studies have shown increased mTOR (mammalian target of rapamycin) activation following aerobic endurance exercise [13]. At the same time, resistance training has consistently been found to increase the levels of AMPK [12]. Both aerobic exercise and resistance exercise have been found to be beneficial for increasing muscle mass, strength, and function. ...
... This is supported by research suggesting that aerobic exercise activates catabolic pathways, while anaerobic exercise stimulates anabolic pathways [10]. There are differences in the intracellular signaling response between the two types of exercises [11,12]. The findings led to the hypothesis of the AMP-activated protein kinase pathway (AMPK)phosphatidylinositol 3-kinase (AKT) switch, suggesting that there is a discrepancy in the signaling responses produced by anaerobic and aerobic exercises, which may not complement each other to optimize muscular adaptations. ...
... The findings led to the hypothesis of the AMP-activated protein kinase pathway (AMPK)phosphatidylinositol 3-kinase (AKT) switch, suggesting that there is a discrepancy in the signaling responses produced by anaerobic and aerobic exercises, which may not complement each other to optimize muscular adaptations. AMPK signaling is for the catabolic pathway and is often associated with aerobic endurance exercises, while AKT signaling is for the anabolic pathway and is often associated with anaerobic or resistance training exercises [12]. However, this theory can be overly simplified and leads to misinterpretation. ...
... Multiple studies have shown increased mTOR (mammalian target of rapamycin) activation following aerobic endurance exercise [13]. At the same time, resistance training has consistently been found to increase the levels of AMPK [12]. Both aerobic exercise and resistance exercise have been found to be beneficial for increasing muscle mass, strength, and function. ...
... Therefore, adding strength training to the endurance training programs of middle-and long-distance runnersknown as concurrent training (Coffey & Hawley, 2017)plays an essential role. When endurance athletes incorporate strength training, they can achieve several important adaptations as described in the literature (Flores-Zamora et al., 2017;Beattie et al., 2017;Blagrove et al., 2017;Blagrove et al., 2018;Gäbler et al., 2018a;Rønnestad & Mujika, 2014;Trowell et al., 2020;. ...
... Furthermore, strength training increases muscle glycogen availability and augmented anaerobic enzyme activity. These combined improvements can lead to enhanced performance across key indicators such as LT, RE (Flores-Zamora et al., 2017;Beattie et al., 2014), and particularly vVO2 max , an essential performance parameter that combines VO2 max and running economy, and allows the identification of aerobic differences among runners, which cannot be attained with VO2 max or RE alone (Billat & Koralsztein, 1996) However, successfully combining strength and endurance represents one of the greatest challenges in training prescription for coaches due to its complexity (Coffey & Hawley, 2017). Indeed, strength and endurance events have traditionally been categorized as activities of opposing nature when considering performance duration and energy metabolism (Berryman et al., 2018a), and the potential endurance and strength adaptations obtained may be attenuated. ...
Objective: This study aimed to analyze the effect of practicing maximum strength (MAX), explosive strength (EXP), or both combined (COMB) on seven runners’ performance indicators: vertical jump (VJ), one-repetition maximum squat (1RM), peak velocity/peak running speed (PV), lactate threshold (LT), middle-distance time trial (TT), maximum oxygen consumption (VO2max), and running economy (RE). Methods: A systematic review (Scopus, Web of Science, Sports Discuss, PubMed) with meta-analysis was conducted following PRISMA standards. Inclusion criteria (PICOS) were: Recreational or well-trained athletes aged 18-45 performing concurrent training for at least five weeks. The search terms used were related to different types of strength/endurance and participants’ age and sports modality. Twenty manuscripts were selected, and quality assessed with PEDro. Results: MAX training is more effective than EXP and COMB in improving VJ, 1RM, and PV, while COMB is more effective than MAX and EXP to enhance TT. MAX is more effective than EXP in improving LT. Concurrent workouts do not provide additional benefits to VO2max. It is unknown which strength modality (MAX, EXP, or COMB) is more effective in improving RE. Conclusion: Concurrent training is more effective than single-mode endurance training for enhancing specific performance variables in adult endurance runners. Middle- and long-distance runners may consider incorporating MAX training to target specific goals (i.e., improving VJ, 1RM, LT, PV) while utilizing COMB training to enhance TT. Certain variables may benefit from EXP. New randomized controlled trials are required to confirm these findings. Keywords: endurance, running, concurrent training, maximum strength, explosive strength
... The training program created through artificial intelligence was suggested to be lacking in generating specific exercises that may improve the muscular endurance of the lower extremities. Training specificity is essential in training to promote desired adaptations (Coffey & Hawley, 2017;Brearley & Bishop, 2019). Although lower extremities exercises were suggested, these target the isotonic contraction of the lower extremities muscles. ...
... The training program was lacking in generating specific exercises that may improve the muscular endurance of the core muscles. Training specificity is essential in training to VOLUME 19 | ISSUE 4 | 2024 | 941 promote desired adaptations (Coffey & Hawley, 2017;Brearley & Bishop, 2019). Although core exercises were suggested, these target the isotonic contraction of the core muscles. ...
The study aims to investigate the effect of a 5-week artificial intelligence-generated calisthenics training program (AIGCTP) on health-related physical fitness components, including flexibility, cardiovascular endurance, and muscular endurance. Utilizing a quasi-experimental design, the study employed a one-group pre-test-post-test design for within-group comparisons and a two-group pre-test-post-test design for between-group comparisons. Participants included 87 untrained collegiate students, divided into the AIGCTP group (43 participants) and a human-made calisthenics training program (HMCTP) group (44 participants), selected via purposive sampling. A paired t-test was used for within-group comparisons, and an independent sample t-test was used for between-group comparisons. The findings indicated that the AIGCTP effectively improved the flexibility of the lower extremities and the muscular endurance of the core and upper extremities. However, female participants did not show significant improvements in any health-related physical fitness components, whereas male participants demonstrated improvements in the flexibility of the lower extremities and muscular endurance of the upper extremities. The HMCTP was effective in improving the flexibility and muscular endurance of the lower and upper extremities for all participants. Between-group comparisons revealed that the cardiovascular endurance of the HMCTP group was significantly superior to that of the AIGCTP group, irrespective of sex. Additionally, males in the HMCTP group exhibited significantly higher muscular endurance of the lower extremities compared to those in the AIGCTP group. The study suggests that AI can be used for fitness training, but professional-made programs are superior in some areas. Future research should replicate these findings, examine more fitness components, and explore longer training durations for further validation.
... Moreover, specific plastic changes might be triggered in a context-dependent manner. For example, endurance and resistance exercise can also increase muscle mass and oxidative capacity, respectively, in untrained individuals [11,12]. Thus, the differentiation between adaptations to endurance and resistance training can be somewhat arbitrary, and a substantial overlap in consequences observed. ...
... Conversely, myofibrillar fractional synthetic rate is only augmented in response to resistance exercise [21]. This flexibility of activation of AMPK, mTORC1 and other regulators in endurance and resistance training could provide an explanation for the overall minimal extent of interference in concurrent training that is observed humans, at least on the recreational level [11,65]. Moreover, the role of these regulators in controlling catabolism and anabolism might not be as strict as initially postulated. ...
Skeletal muscle plasticity enables an enormous potential to adapt to various internal and external stimuli and perturbations. Most notably, changes in contractile activity evoke a massive remodeling of biochemical, metabolic and force-generating properties. In recent years, a large number of signals, sensors, regulators and effectors have been implicated in these adaptive processes. Nevertheless, our understanding of the molecular underpinnings of training adaptation remains rudimentary. Specifically, the mechanisms that underlie signal integration, output coordination, functional redundancy and other complex traits of muscle adaptation are unknown. In fact, it is even unclear how stimulus-dependent specification is brought about in endurance or resistance exercise. In this review, we will provide an overview on the events that describe the acute perturbations in single endurance and resistance exercise bouts. Furthermore, we will provide insights into the molecular principles of long-term training adaptation. Finally, current gaps in knowledge will be identified, and strategies for a multi-omic and -cellular analyses of the molecular mechanisms of skeletal muscle plasticity that are engaged in individual, acute exercise bouts and chronic training adaptation discussed.
... Common applications of IF include whole-day fasting, alternate-day fasting, modified-alternate-day fasting, and time-restricted eating (TRE) (5). TRE may be the easiest IF strategy to follow because it simply involves consuming one's daily calories within a designated eating window (e.g., 8 hours) followed by a prolonged fasting window (e.g., 16 hours) (24,25). Another potential benefit of TRE is the creation of a caloric deficit despite not actively counting calories (24,40). ...
... Concurrent training (CT), defined as performing aerobic training (AT; cycling, jogging, rowing, etc.) and RT during the same session, day, week, month, or training block, allows fitness enthusiasts to pursue a variety of "aerobic" and "resistance" adaptations (8,16). Early CT studies demonstrated that AT blunted typical RTadaptations, such as hypertrophy, which became known as the interference effect (85). ...
Time-restricted eating (TRE) is an application of intermittent fasting where an individual consumes their calories in a specific eating window (e.g., 8 hours) followed by a prolonged fasting window (e.g., 16 hours). Several randomized controlled trials have analyzed the combined effect of resistance training (RT) and TRE on physical adaptations, including fat mass (FM) loss, fat-free mass (FFM) retention, hypertrophy, local muscular endurance, power, and strength. In this mini review, we highlight the methodology and results from these studies and conclude by providing practical application suggestions for fitness professionals striving to maximize RT + TRE with their clientele. Generally, RT + TRE leads to positive body composition changes, including FM loss and FFM retention, which culminates in improved body fat percentage. Similarly, RT + TRE consistently stimulates positive neuromuscular adaptations, such as increased hypertrophy, local muscular endurance, power, and strength. When positive changes are not observed, and when safely implemented, RT + TRE rarely confers negative effects on the abovementioned adaptations. In short, RT + TRE may be a beneficial dietary and exercise strategy to improve body composition and muscular fitness. However, there are several caveats for practitioners to consider, which are discussed at length in this article.
... Moreover, although the bene ts of endurance and RT are numerous, concurrent training, in which resistance and endurance exercises are performed simultaneously, may attenuate the adaptation of RT when compared with either training method alone, which is called the concurrent training effect [6][7][8][9][10]. This phenomenon was rst described in 1980 by Robert C. Hickson [11]. ...
... This phenomenon was rst described in 1980 by Robert C. Hickson [11]. Regarding molecular mechanisms, previous studies have focused on the potential antagonism between the AMPK (an upstream activator of PGC-1α) and mTORC1 signaling cascades to elucidate the interference effect of concurrent training [6][7][8][9][10]. In rodent models, after resistance exercise, animals treated with AICAR, the AMPK activator, display a clear reduction in mTORC1 activation as previously described [12]. ...
Resistance training (RT) is important for skeletal muscle health. However, compared with RT implemented alone, concurrent training can attenuate RT adaptations. We verify the effects of RT on muscle-enriched or hypertrophy-related miRNAs, mammalian target of rapamycin complex 1 (mTORC1) anabolic signaling proteins, and oxidative metabolism-related proteins in mice with different endurance muscle Phenotype. In the present study, we found that muscle-specific overexpression of PGC-1alpha attenuated RT adaptations and resulted in different expression of miR-222-3p and miR-206-3p after RT. The expression level of miR-206-3p and miR-222-3p in Wt+ mice (wild-type trained mice) was significantly higher than that in Tg+ mice (MCK-PGC-1α transgenic trained mice). This suggested that discordant miR-222-3p and miR-206-3p expression levels after RT may play a role in the mechanism contributing to the interference effects. With regard to protein expression,there was no difference in mTORC1 between the genotypes. Furthermore, the levels of parameters for oxidative metabolism were significantly higher in Tg mice than in Wt mice. Our study indicated miR-222-3p and miR-206-3pas novel molecules that could provide a new research direction into the mechanisms underlying the concurrent training effect.
... Advances in exercise physiology will be instrumental in optimizing variables for cardiorespiratory training (intensity based on VO 2 max and peak HR determined in CPET, duration, recovery, and frequency) and strength training (exercise selection, relative intensity -%RM-, effort grade/character, number of repetitions, daily and weekly volume, and rest between sets). This body of knowledge also encompasses the definition of "concurrent training", which combines both resistance and cardiorespiratory training in a single program and/or training session [12]. ...
... Previous studies have demonstrated that the optimal distribution of concurrent training to maximize benefits and minimize interference in acute and long-term adaptations is to conduct strength training at the beginning of the session, followed by cardiorespiratory exercise [19,25]. Moreover, it has been observed that the benefits of concurrent training in strength and cardiorespiratory aspects surpass those observed with either modality performed exclusively, especially in sedentary, beginners, and intermediate individuals [12]. Finally, recent advancements in exercise physiology have underscored the role of skeletal muscle as an endocrine tissue in cardiovascular risk prevention [26]. ...
Background: Exercise training in patients with HCM has evidenced benefits on functional capacity, cardiac function, and a reversion of adverse cardiac remodeling. The objective of this study was to assess the effect of a concurrent resistance and cardiorespiratory training program on functional capacity, biochemical parameters, and echocardiographic variables in a pilot group. Methods: Two HCM patients were evaluated before and after 12 weeks of individualized concurrent training with two sessions/week. Pre- and post-training data were compared for each patient. Evaluations included a cardiopulmonary exercise test (CPET), body composition, echocardiography, electrocardiography, and blood analysis. Results: Training promoted an increase in functional capacity (+4 mL·kg⁻¹·min⁻¹), ventilatory thresholds, and other CPET-derived variables associated with a better prognosis and long-term survival. Muscular mass was augmented (0.8 and 1.2 kg), along with a mean increase of 62% in upper and lower body strength. Echocardiographic features demonstrated the maintenance of cardiac function with signs of positive left ventricular remodeling and an improvement in diastolic function. Blood analyses, including cardiac troponins and NT-proBNP, displayed uneven changes in each patient, but the values fell into normal ranges in both cases. Conclusions: The available data suggest a positive effect of concurrent resistance and cardiorespiratory training on patients’ functional capacity and cardiac function that may improve their functional class, quality of life, and long-term prognosis. The replication of this protocol in a larger cohort of patients is warranted to confirm these preliminary results.
... Therefore, adding strength training to the endurance training programs of middle-and longdistance runners -known as concurrent training [10]-plays an essential role. When endurance athletes incorporate strength training, they can achieve several important adaptations as described in the literature [3,4,[11][12][13][14][15][16]. ...
... However, successfully combining strength and endurance represents one of the greatest challenges in training prescriptions for coaches due to its complexity [10]. Indeed, strength and endurance events have traditionally been categorized as opposing activities when considering performance duration and energy metabolism [19]. ...
The effectiveness of combining strength-specific training with endurance training to
enhance the performance of endurance runners remains uncertain. This study aimed to analyze
effect of practising maximum-strength (MAX), explosive strength (EXP) or both combined (COMB)
on seven runners’ performance-indicators: vertical jump (VJ), one-repetition-maximum-squat
(1RM), peak-velocity/peak-running-speed (PV), lactate-threshold (over incremental-test-protocols,
LT), middle-distance-time-trial (TT), maximum-oxygen-consumption (VO2max), running-economy
(RE). Systematic-review (Scopus, Wed of Science, Sports Discuss, PubMed) with meta-analysis was
conducted following PRISMA standards. Inclusion-criteria (PICOS) were: recreational or welltrained
athletes aged 18-45 performing concurrent-training ≥five-week. Used search-terms were
related to different types of strength/endurance, participants’ age, sport-modality. 20 manuscripts
were selected, quality-assessed with PEDro. MAX training is more effective than EXP, COMB in
improving VJ, 1RM, PV, while COMB is more effective than MAX, EXP to enhance TT. MAX is more
effective than EXP in improving LT. Concurrent-workouts do not provide additional benefits to
VO2max. It is unknown which strength-modality (MAX, EXP or COMB) is more effective in
improving RE. Concurrent-training is more effective than single-mode-endurance-training for
enhancing specific performance-variables in adult-endurance-runners. Middle-, long-distancerunners
may consider incorporating MAX-training to target specific goals, e.g., improving VJ, 1RM,
LT, PV while utilizing COMB-training to enhance TT. Certain variables may benefit from EXP. New
randomized-controlled-trials are required to confirm these findings.
... Muscle architecture is a concept applied to the organization of skeletal muscle components such as fascicle length, pennation angle, and muscle thickness, which influence the muscle size, for example, the cross-sectional area (12,19). This muscular plasticity resulting from the training practice gives its practitioner a great performance (16,20) and becomes increasingly specific with the increase in the training level (7). ...
... If FFT provides the appearance of this effect, the adaptations between these two training methods may differ, which could influence the physical performance of FFT practitioners. Given that this effect may be evident in more trained individuals (7,32), it is unknown whether there is a difference between the muscle architecture of experienced practitioners in FFT and practitioners trained only in ST. ...
Functional Fitness Training (FFT) is a very popular training method in recent years. However, the combination of aerobic and strength components of this training method raised the hypothesis of impaired strength and muscle structure when compared to Strength Training (ST). Thus, the study aimed to compare muscle architecture and strength between FFT and ST, and the relationship between muscle architecture and maximum strength performance. Males (28.46 ± 6.03 years), nonathletes, and practitioners for two years in FFT (n = 8) and ST (n = 8), in addition to males classified as physically active (n = 8) were recruited. Muscle architecture of the rectus femoris (RF) and vastus lateralis (VL) of the thigh were evaluated with the aid of B-mode ultrasound and maximum strength in the back squat through the one-repetition maximum test. For muscle architecture, the fascicle length (FL), pennation angle (PAn), and muscle thickness (MT) were evaluated, in addition to the cross-sectional area (CSA). The FL, PAn, MT, and CSA of the RF and VL did not differ between the FFT and ST groups. Similarly, maximum strength did not differ between the FFT (152 ± 23.68 kg) and ST (151.88 ± 14.77 kg) groups. A significant relationship was observed between the PAn of the RF and the maximum strength (r =0.862; p =0.006) of FFT practitioners. The muscle architecture, CSA, and muscle strength do not differ between FFT and ST male practitioners, and PAn of the RF correlates with the maximum force for FFT practitioners.
... For instance, an inter-modality interval of less than 6 h between ET and RT sessions has been demonstrated to significantly impinge upon the development of muscular strength and power [63]. A plethora of studies have endeavored to explicate this phenomenon through a multifaceted lens, encompassing the overtraining hypothesis [64], concurrent hypotheses of acute response, and long-term adaptation [64], as well as the molecular interference hypothesis and the AMPK-Akt pathway hypothesis [65]. Intriguingly, the findings of the current investigation reveal that within a pediatric and adolescent cohort, a CT protocol amalgamating ET and RT modalities within a singular session (CRE) is superior to a segregated protocol (CRED) with respect to augmenting lower limb muscular maximal strength and explosive power. ...
The decline in fitness levels among children and adolescents underscores the urgent need for effective exercise interventions. Aerobic endurance training (ET) and resistance training (RT) are vital for physical development in this demographic. This study employs multivariate and network meta‐analysis (NMA) to assess the impact of concurrent training (CT), which integrates both ET and RT, on youth physical fitness. The objective is to identify the distinct advantages of CT over either ET or RT alone, emphasizing demographic and training‐specific variables. A systematic literature review of publications from 1980 onward was conducted through ISI Web of Science, PubMed/MEDLINE, and SPORTDiscus databases, adhering to the PICOS criteria for study selection. Data were analyzed using univariate, multivariate, and network meta‐analyses in Stata 17.0, focusing on cardiorespiratory fitness and muscular strength. The methodological quality and risk of bias were evaluated using the PEDro scale and Egger's test, along with sensitivity analyses and meta‐regression to explore heterogeneity and publication bias. This analysis included 36 studies with 2658 participants (mean age: 14.32 ± 2.29 years) from an initial 11 074 publications, indicating low bias risk (PEDro scores ≥ 6). Univariate meta‐analysis showed no significant differences in maximal oxygen uptake (VO2max) between CT and ET (standardized mean difference [SMD] = 0.01; 95% confidence interval [CI]: −0.23 to 0.25; p = 0.93). In contrast, CT significantly improved countermovement jump (CMJ) compared to RT alone (SMD = 0.19; 95% CI: 0.01–0.36; p = 0.04). Multivariate analysis confirmed notable enhancements in endurance and explosiveness for CT compared to ET or RT. NMA indicated significant improvements in lower limb strength, CMJ, and VO2max across interventions compared to controls, with the consecutive resistance training followed by ET (CRE) group yielding the most significant CMJ improvement (SMD = 0.27; 95% CI: 0.07–0.47). Isolated RT showed the highest lower limb strength improvement (SUCRA score 80.1%), while CRE excelled in CMJ advancements (SUCRA score 93.4%), and the CRED group (alternating ET and RT) led in VO2max improvements (SUCRA score 81.6%). Furthermore, high‐intensity interval training (HIIT) significantly enhanced VO2max compared to team sports. This meta‐analysis emphasizes the effectiveness of CT in improving muscle power and VO2max in children and adolescents, surpassing isolated ET or RT, and advocates for integrating ET and RT to optimize physical performance. Future research should explore the mechanisms underlying these enhancements.
Trial Registration: PROSPERO registration number CRD42022368452
... [ Downloaded from jsmt.khu.ac.ir on 2024-[10][11][12][13][14][15][16][17][18][19][20][21][22][23] ...
... Concurrent training (CT) involves the integration of RT and ET into a unified training protocol (3) and has been shown to augment muscle strength, anaerobic power, aerobic capacity, and maximum velocity contractions (4)(5)(6)(7)(8). Despite the favorable adaptations observed with CT, some studies have demonstrated diminished enhancements in muscle strength, power, and hypertrophy when compared to RT conducted independently, which is often referred to as the "interference effect" (9)(10)(11)(12)(13)(14). The literature presents contradictory findings about dampened anabolic training responses within this paradigm, which may be influenced by factors such as participants' training experience, the order in which training sessions are conducted, and the specific forms of exercise implemented (15)(16)(17)(18). ...
Background
We assessed the relationship of changes in upper and lower body lean mass with muscle strength, endurance and power responses following two high protein diets (1.6 or 3.2 g.kg-1.d⁻¹) during 16 weeks of either concurrent training (CT) or resistance training (RT) in resistance-trained young males.
Methods
Forty-eight resistance-trained young males (age: 26 ± 6 yr., body mass index: 25.6 ± 2.9 kg.m⁻²) performed 16 weeks (four sessions·wk.⁻¹) of CT or RT with either 1.6 g.kg-1.d⁻¹ protein (CT + 1.6; n = 12; RT + 1.6; n = 12) or 3.2 g.kg-1.d⁻¹ protein (CT + 3.2; n = 12; RT + 3.2; n = 12). Relationships between upper (left arm + right arm + trunk lean mass) and lower body (left leg + right leg lean mass) lean mass changes with changes in muscle performance were assessed using Pearson’s correlation coefficients.
Results
For upper body, non-significant weak positive relationships were observed between change in upper body lean mass and change in pull-up (r = 0.183, p = 0.234), absolute chest press strength (r = 0.159, p = 0.302), chest press endurance (r = 0.041, p = 0.792), and relative chest press strength (r = 0.097, p = 0.529) while non-significant weak negative relationships were observed for changes in absolute upper body power (r = −0.236, p = 0.123) and relative upper body power (r = −0.203, p = 0.185). For lower body, non-significant weak positive relationships were observed between the change in lower body lean mass with change in vertical jump (r = 0.145, p = 0.346), absolute lower body power (r = 0.109, p = 0.480), absolute leg press strength (r = 0.073, p = 0.638), leg press endurance (r < 0.001, p = 0.998), relative leg press strength (r = 0.089, p = 0.564), and relative lower body power (r = 0.150, p = 0.332).
Conclusion
Changes in muscle strength, endurance and power adaptation responses following 16 weeks of either CT or RT with different high protein intakes were not associated with changes in lean mass in resistance-trained young males. These findings indicate that muscle hypertrophy has a small, or negligible, contributory role in promoting functional adaptations with RT or CT, at least over a 16-week period.
... Too low a training intensity and volume might contribute to another problem when trying to investigate the sequence effect. According to the study by Coffey and Hawley [49], the adaptations resulting from single-mode training (e.g., strength or endurance alone) and concurrent training are largely comparable in the first days/weeks of training for an untrained individual. They further hypothesize that it could be because the body does not differentiate between strength and endurance-like adaptational signals, likely because strength and endurance training is conducted at quite a moderate volume and intensity. ...
This review investigates the effect of two different concurrent training sequences on endurance performance. The sequences investigated are Endurance–Resistance (ER) and Resistance–Endurance (RE). A literature search is conducted of the SPORTDiscus and Medline databases. The included studies are randomized control trials, which compare the effect of ER and RE on at least one endurance performance variable. A PEDro scale is used to assess the methodological quality of the articles in this review. Of a total of 152 articles identified during the initial screening, 15 studies meet the inclusion criteria. These studies include 426 participants (298 males and 128 females), with 212 of the participants training with ER and 214 with RE. The results are presented as the percentage change of the mean from pre- to post-test. All the studies show an improvement in endurance from pre to post for both interventions, except for the RE group in one study. This review finds small and non-conclusive sequence effects between ER and RE, suggesting that the sequence of concurrent training is not of great importance in relation to endurance performance.
... Conclusions should be cautiously made since there are still relatively few clinical studies on the relationship between probiotics and physical performance, and each research typically only involves a limited number of individuals and makes use of various exercise regimes. Probiotics must be living organisms in order to meet the term (Marttinen et al., 2020;Appukutty et al., 2015;Coffey V et al., 2017). ...
Aim: The purpose of this umbrella review is to bring together the most recent reviews concerning the relationship between gut-microbiota and sport activity. Materials and Methods: A literature search was conducted through PubMed and focused on reviews and systematic reviews published between 2015 and June 2021 that dealt with the topic of microbiota and physical activity. Only articles written in English and published in peer-reviewed journals were considered. Key words related to the term microbiota alone or in conjunction with other terms such as "supplements", "diet", "probiotics", "prebiotics", "health", "physical activity", and "pathogens" were analyzed. The selection process was done first by analyzing the titles, then the abstracts, and finally the full text. Results: After screening the title and abstract, 29 articles were excluded. Therefore, 20 studies were included in the present umbrella review. The figure shows the steps of the selection process (Figure 1). The specifications of the presented articles are listed in Table 2. Conclusions: Exercise appears to be an environmental factor that can determine changes in the gut microbial composition with possible benefits for the host. Increased microbiota diversity improves metabolic profile and immunological responses and may provide a possible biomarker for health improvement. Exercise altered microbiota could be used to look for new approaches in the treatment of metabolic and inflammatory diseases.
... The results revealed that the swim-to-exhaustion time was the longest for SPF mice and the shortest for GF mice, indicating a compromised sports performance in the absence of a gut microbiota [60]. Although the effects of probiotics supplementation have been studied in athletes and physically active populations, the small number of participants, the different exercise intervention programs implemented, and the different training histories of the participants may have influenced the outcomes [61]; therefore, the results remain controversial. However, a review conducted by Marttinen et al. as summarized several benefits of probiotics for the athlete. ...
The intestinal tract of humans harbors a dynamic and complex bacterial community known as the gut microbiota, which plays a crucial role in regulating functions such as metabolism and immunity in the human body. Numerous studies conducted in recent decades have also highlighted the significant potential of the gut microbiota in promoting human health. It is widely recognized that training and nutrition strategies are pivotal factors that allow athletes to achieve optimal performance. Consequently, there has been an increasing focus on whether training and dietary patterns influence sports performance through their impact on the gut microbiota. In this review, we aim to present the concept and primary functions of the gut microbiota, explore the relationship between exercise and the gut microbiota, and specifically examine the popular dietary patterns associated with athletes’ sports performance while considering their interaction with the gut microbiota. Finally, we discuss the potential mechanisms by which dietary patterns affect sports performance from a nutritional perspective, aiming to elucidate the intricate interplay among dietary patterns, the gut microbiota, and sports performance. We have found that the precise application of specific dietary patterns (ketogenic diet, plant-based diet, high-protein diet, Mediterranean diet, and high intake of carbohydrate) can improve vascular function and reduce the risk of illness in health promotion, etc., as well as promoting recovery and controlling weight with regard to improving sports performance, etc. In conclusion, although it can be inferred that certain aspects of an athlete’s ability may benefit from specific dietary patterns mediated by the gut microbiota to some extent, further high-quality clinical studies are warranted to substantiate these claims and elucidate the underlying mechanisms.
... For the short exercise protocols tested in this study, we did not see significant differences in peak magnitude of changes associated with the order of concurrent training, as have been described in some studies (Coffey & Hawley, 2017). This may be because the model does not account for the metabolic costs of exercise and the fact that mitochondrial biogenesis and protein turnover require more cellular energy than is needed for metabolic homeostasis. ...
Exercise‐induced muscle adaptations vary based on exercise modality and intensity. We constructed a signalling network model from 87 published studies of human or rodent skeletal muscle cell responses to endurance or resistance exercise in vivo or simulated exercise in vitro. The network comprises 259 signalling interactions between 120 nodes, representing eight membrane receptors and eight canonical signalling pathways regulating 14 transcriptional regulators, 28 target genes and 12 exercise‐induced phenotypes. Using this network, we formulated a logic‐based ordinary differential equation model predicting time‐dependent molecular and phenotypic alterations following acute endurance and resistance exercises. Compared with nine independent studies, the model accurately predicted 18/21 (85%) acute responses to resistance exercise and 12/16 (75%) acute responses to endurance exercise. Detailed sensitivity analysis of differential phenotypic responses to resistance and endurance training showed that, in the model, exercise regulates cell growth and protein synthesis primarily by signalling via mechanistic target of rapamycin, which is activated by Akt and inhibited in endurance exercise by AMP‐activated protein kinase. Endurance exercise preferentially activates inflammation via reactive oxygen species and nuclear factor κB signalling. Furthermore, the expected preferential activation of mitochondrial biogenesis by endurance exercise was counterbalanced in the model by protein kinase C in response to resistance training. This model provides a new tool for investigating cross‐talk between skeletal muscle signalling pathways activated by endurance and resistance exercise, and the mechanisms of interactions such as the interference effects of endurance training on resistance exercise outcomes.
... Those with the lowest baseline fitness level and self-efficacy likely improved the most during the high-intensity functional training program because they were further from their maximum fitness potential. It has been shown that combined strength and endurance training improves both muscular and aerobic fitness to a higher extent that either training method alone (Coffey and Hawley, 2017). Similar results have been presented also in military settings (Burley et al., 2020). ...
Background
Exercise self-efficacy is a crucial aspect of adopting and maintaining a physically active lifestyle. Regular physical activity may enhance exercise self-efficacy. This study aimed to investigate the baseline associations of physical fitness, physical activity, and body composition with exercise self-efficacy and the effects of military service on exercise self-efficacy. Methods: The sample consisted of healthy young Finnish conscripts (n = 243) undergoing military service. The participants were divided into two groups: an intervention group undergoing a high-intensity functional training program (n = 113) and a control group undergoing traditional physical training within their military service (n = 130). Exercise self-efficacy (adoption and barrier) and aerobic and muscular fitness were measured thrice (baseline, month 3, and month 5). Self-reported leisure-time physical activity and measured fat percentage were collected at baseline.
Results
Adoption and barrier exercise self-efficacy correlated positively with aerobic and muscular fitness and leisure time physical activity (r = 0.33–0.59, p < 0.001), and barrier self-efficacy negatively with fat percentage (r = −0.15, p < 0.05) at baseline. No changes in adoption (time p = 0.912) and barrier self-efficacy (time p = 0.441) occurred during the military service. There were no differences between groups in these changes (group × time interaction p = 0.643 for adoption self-efficacy and p = 0.872 for barrier self-efficacy). Change in muscular fitness correlated positively with change in barrier self-efficacy in the high-intensity functional training group (r = 0.35, p < 0.05). Conclusions: Exercise self-efficacy is positively associated with physical fitness and physical activity among young males. However, military service, whether it involves high-intensity functional physical training or more diverse traditional physical training, does not improve exercise self-efficacy.
... The changes in locomotor and high-intensity muscle activities during advanced ageing generates a sort of pure aerobic stimulus, slow walking, likely contributing to a shift toward the aerobic muscle phenotype in the lower limbs (Coffey & Hawley, 2017). Certainly, this phenomenon is coupled with other intrinsic factors, which cause atrophy and the disappearance of fast-glycolytic fibres (Lexell, 1995;Lexell et al., 1988;Schiaffino & Reggiani, 2011). ...
This study aimed to determine which physiological factors impact net efficiency (ηnet) in oldest‐old individuals at different stages of skeletal muscle disuse. To this aim, we examined ηnet, central haemodynamics, peripheral circulation, and peripheral factors (skeletal muscle fibre type, capillarization and concentration of mitochondrial DNA [mtDNA]). Twelve young (YG; 25 ± 2 years), 12 oldest‐old mobile (OM; 87 ± 3 years), and 12 oldest‐old immobile (OI; 88 ± 4 years) subjects performed dynamic knee extensor (KE) and elbow flexors (EF) exercise. Pulmonary oxygen uptake, photoplethysmography, Doppler ultrasound and muscle biopsies of the vastus lateralis and biceps brachii were used to assess central and peripheral adaptations to advanced ageing and disuse. Compared to the YG (12.1 ± 2.4%), the ηnet of lower‐limb muscle was higher in the OM (17.6 ± 3.5%, P < 0.001), and lower in the OI (8.9 ± 1.9%, P < 0.001). These changes in ηnet during KE were coupled with significant peripheral adaptations, revealing strong correlations between ηnet and the proportion of type I muscle fibres (r = 0.82), as well as [mtDNA] (r = 0.77). No differences in ηnet were evident in the upper‐limb muscles between YG, OM and OI. In view of the differences in limb‐specific activity across the lifespan, these findings suggest that ηnet is reduced by skeletal muscle inactivity and not by chronological age, per se. Likewise, this study revealed that the age‐related changes in ηnet are not a consequence of central or peripheral haemodynamic adaptations, but are likely a product of peripheral changes related to skeletal muscle fibre type and mitochondrial density. image
Key points
Although the effects of ageing and muscle disuse deeply impact the cardiovascular and skeletal muscle function, the combination of these factors on the mechanical efficiency are still a matter of debate.
By measuring both upper‐ and lower‐limb muscle function, which experience differing levels of disuse, we examined the influence of central and peripheral haemodynamics, and skeletal muscle factors linked to mechanical efficiency.
Across the ages and degree of disuse, upper‐limb muscles exhibited a preserved work economy. In the legs the oldest‐old without mobility limitations exhibited an augmented mechanical efficiency, which was reduced in those with an impairment in ambulation. These changes in mechanical efficiency were associated with the proportion of type I muscle fibres.
Recognition that the mechanical efficiency is not simply age‐dependent, but the consequence of inactivity and subsequent skeletal muscle changes, highlights the importance of maintaining physical activity across the lifespan.
... Prior research indicates that short interval times between strength and endurance training could significantly influence interference effects. 34,51,71,101 This factor warrants further investigation for a comprehensive understanding. ...
Objective
This study aims to compare, through quantitative analysis, the effectiveness of different endurance training types on increasing lower limb strength and muscle cross-sectional area (MCSA) in concurrent training.
Methods
This systematic literature search was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) [PROSPERO ID: CRD42023396886]. Web of Science, SportDiscuss, Pubmed, Cochrane, and Scopus were systematically searched from their inception date to October 20, 2023.
Results
A total of 40 studies (841 participants) were included in this meta-analysis. MCSA analysis showed that, compared to resistance training alone, concurrent high-intensity interval running training and resistance training and concurrent moderate-intensity continuous cycling training and resistance training were more effective (SMD = 0.15, 95% CI = −0.46 to 0.76, and SMD = 0.07, 95% CI = −0.24 to 0.38 respectively), while other modalities of concurrent training not. Lower body maximal strength analysis showed that all modalities of concurrent training were inferior to resistance training alone, but concurrent high-intensity interval training and resistance training showed an advantage in four different concurrent training modalities (SMD = −0.08, 95% CI = −0.25 to 0.08). For explosive strength, only concurrent high-intensity interval training and resistance training was superior to resistance training (SMD = 0.06, 95% CI = −0.21 to 0.33).
Conclusion
Different endurance training types have an impact on the effectiveness of concurrent training, particularly on lower limb strength. Adopting high-intensity interval running as the endurance training type in concurrent training can effectively minimize the adverse effects on lower limb strength and MCSA.
... However, the effects of caffeine supplementation on performance during concurrent training remain poorly investigated. Given that concurrent training programs are highly recommended for enhancing sport performance and overall health (Berryman et al., 2019;Cadore & Izquierdo, 2013;Coffey & Hawley, 2017;Laursen & Buchheit, 2019;Mijwel et al., 2018), it is crucial to investigate whether caffeine can enhance resistance exercise performance when it is preceded by aerobic exercise, or if it can at least mitigate the interference effect on it. This gap in knowledge warrants further exploration in order to optimize training strategies and maximize the benefits of concurrent training. ...
Purpose: The aim of the present study was to investigate the effects of acute caffeine supplementation on the performance during a session of resistance training alone (RT) or in combination with aerobic training (i.e. concurrent training; CT). Method: Fourteen resistance-trained men (23.1 ± 4.2 years) were recruited and performed both RT and CT under three different conditions: control (CONT), placebo (PLA), and caffeine (CAF; 6 mg.kg−1) for a total of six experimental conditions. Results: Both total and per set number of repetitions, and total volume load were lower during CT as compared to RT, irrespective of the supplementation condition (all p < .001), whereas a supplementation main effect was observed for the total number of repetitions (p = .001), the number of repetitions in the first (p = .002) and second sets (p = .001), and total volume load (p = .001). RPE values were higher after the CT sessions than after the RT sessions (p < .001), whereas no differences were observed between supplementation conditions (p = .865). Conclusions: Caffeine supplementation was not sufficient to minimize the acute interference effect on strength performance in a CT session when compared to RT alone. In contrast, caffeine improved strength performance during the first set of both CT and RT, while maintaining a similar RPE between the supplementation conditions. However, the overall effect was small.
... Numerous studies have indicated that combining resistance training and endurance training may lead to interference effects and impact athletes' training outcomes [72][73][74][75][76]. However, when athletes engage in HIFT training, this interference effect may not be observed [77]. ...
Objective
This study aims to meta-analyze the impact of high-intensity functional training on athletes’ physical fitness and sport-specific performance.
Methods
A systematic search was conducted in five well-known academic databases (PubMed, Scopus, Web of Science, EBSCOhost, and the Cochrane Library) up to July 1, 2023. The literature screening criteria included: (1) studies involving healthy athletes, (2) a HIFT program, (3) an assessment of outcomes related to athletes’ physical fitness or sport-specific performance, and (4) the inclusion of randomized controlled trials. The Physical Therapy Evidence Database (PEDro) scale was used to evaluate the quality of studies included in the meta-analysis.
Results
13 medium- and high-quality studies met the inclusion criteria for the systematic review, involving 478 athletes aged between 10 and 24.5 years. The training showed a small to large effect size (ES = 0.414–3.351; all p < 0.05) in improving upper and lower body muscle strength, power, flexibility, and sport-specific performance.
Conclusion
High-intensity functional training effectively improves athletes’ muscle strength, power, flexibility, and sport-specific performance but has no significant impact on endurance and agility. Future research is needed to explore the impact of high-intensity functional training on athletes’ speed, balance, and technical and tactical performance parameters.
... The reduction in adiposity indicators (FM, BF, and visceral fat) is related to a negative energy balance, higher energy expenditure, and lower caloric consumption [29,30], associated with the food education classes and increased level of supervised physical activity in the interventions. In addition, the increase in LM, FFM, and SMM is associated with the stimulus provided by competing exercises: untrained individuals can bring positive physiological adjustments to muscle hypertrophy and cardiorespiratory fitness [31]. The concatenated responses to muscle hypertrophy suggest that the volume and intensity used in training sessions were adequate to increase LM, FFM, and SMM after the intervention period. ...
Adolescence is a complex period of human development in which young people are susceptible to unhealthy behaviors, such as physical inactivity and an unbalanced diet. This study aimed to analyze the effects of 12 weeks of multi-disciplinary family and individual intervention on cardiometabolic risk parameters in overweight and obese adolescents and compare sub-groups, considering possible differences between sexes (males vs. females vs. intervention approach). Fortythree adolescents (13.73 ± 2.46 years old) of both sexes were divided into two groups: family group (FG) (n = 21; 14.24 ± 2.61 years old) and individual group (IG) (n = 22; 13.23 ± 2.27 years old). The following parameters were evaluated: anthropometry (body weight, height, waist circumference (WC), hip circumference (HC), abdominal circumference (AC), calculation of body mass index (BMI), and waist–hip ratio (WHR)), body composition (fat mass (FM), lean mass (LM), fat-free mass
(FFM), skeletal muscle mass (SMM), body fat percentage (BF), and visceral fat), biochemical measures (fasting glucose, triglycerides (TG), total cholesterol (TC), low-density lipoproteins (LDLc), and high-density lipoproteins (HDL-c)), and the measurement of systolic and diastolic blood pressure (SBP and DBP) before and after the interventions. The multi-disciplinary interventions occurred for 12 weeks (three days a week lasting 1 h and 30 min, in which 30 min were dedicated to
theoretical interventions (nutrition: nutritional education and psychology: psychoeducation) and 1h to physical exercises. A time effect was observed for LM, FFM, SMM, FM, and HDL-c, with higher values after intervention and a significant decrease for FM, BF, visceral fat, fasting glucose, TG, TC, LDL-c, and DBP (p < 0.05). However, no group, sub-group, or interaction effects were observed
when comparing FG, IG, or sexes (p > 0.05). The responses of the present study show that both multidisciplinary approaches (family and individual) promoted improvement in the body composition indicators, biochemical markers, and DBP of overweight and obese adolescents independently of the intervention group. Given this finding, health professionals, families, and adolescents could choose the type of intervention based on their preferences.
... Combining both strength and aerobic components in the same session, as required by the CT protocol, can have an impact on the biological adaptations induced by the exercise. The magnitude of performance development appears to be dependent on several factors, including the intensity, duration, and order of execution of the exercises, as well as characteristics of the animals (age, sex, and training status) and study duration [48][49][50]. However, the evidence demonstrated that concomitant aerobic and strength training does not compromise maximal strength development [51]. ...
A sedentary lifestyle, coupled with a decrease in estrogen, impairs bone homeostasis, favoring to the development of osteopenia and osteoporosis, both recognized as risk factors for fractures. Here, we investigated the quality of the femur, particularly the femur neck region, and the ambulation performance of senescent rats subjected to three different physical training protocols during the periestropause period. Forty-eight female rats, 18 months of age, were subjected to a 120-day training period, three times a week. The rats were distributed into four groups: aerobic training (AT), strength training (ST), concurrent training (CT), or no training (NT). After the experimental period, at 21 months of age, ambulation performance and femur were analyzed using microtomography, Raman stereology, densitometry, and mechanical strength tests. The results demonstrated greater remodeling activity and improvement in resistance and bone microarchitecture in the femur neck of senescent female rats after undergoing physical training. Our verified higher intensities of bands related to collagen, phosphate, amide III, and amide I. Furthermore, the analysis of the secondary collagen structures indicated alterations in the collagen network due to the exercise, resulting in increased bone strength. Both AT and strength-based training proved beneficial, with AT showing greater adaptations in bone density and stiffness in the femur, while strength-based training greater adaptations in trabecular and cortical structure. These insights contribute to the understanding of the potential interventions for preventing osteopenia and osteoporosis, which are critical risk factors for fractures.
... Physical training has bene cial effects on blood vessel formation and enhancement in capillary density, a process called angiogenesis (1, 2, 3). Several types of physical activities such as endurance, resistance, interval or concurrent training accompany with new capillaries production mediated by proliferation and migration of endothelial cells via reducing barometric pressure of intracellular oxygen and recruiting oxidative processes (4,5). Previous studies certi ed that these changes regulate physiological responses through increased peripheral blood ow, oxygen supply and energy availability by enhancing exchange duration between the blood and active tissues, and arterio-venous oxygen difference and Volume of O 2 maximum (1,6,7,8). ...
Background
Angiogenesis is a beneficial process leading to capillary enhancement, which can trigger in response to physical training.
Aims
The present study aimed to investigate the changes in physiological factors involved in angiogenesis in response to circuit or traditional resistance training.
Methods
Following the pre-test, Thirty-six healthy sedentary students (age: 21.1 ± 2.3 years; height: 172.7 ± 5.1 cm) were randomly divided into Circuit Resistance Training (CRT) (4 circles/3 times a week/8 weeks circuit performance/50–55% 1 Repetition Maximum; n = 12), Traditional Resistance Training (TRT) (8 repetition/3 set/3 time per week/8 weeks of same movements with 75% 1RM followed by 2 minutes break between the sets; n = 12) and the control group (n = 12). We examined the responses of Vascular Endothelial Growth Factor (VEGF), plasma level of growth hormone (GH), and basic Fibroblast Growth Factor (bFGF).
Results
Both of CRT and TRT protocols resulted in significant increases in post-test compared to pre-test, in VEGF (p = 0.00), GH (p = 0.04), and bFGF (p = 0.00). In addition, the magnitude of changes in VEGF and GH were significantly greater than the control group in post-test (p = 0.03, and 0.001, respectively). In addition, there was a strong correlation between absolute value of GH and VEGF (r = 0.74 and r = 0.71) following CRT (p = 0.01) and TRT (p = 0.02).
Conclusions
This study demonstrated that CRT and TRT might enhance angiogenesis through increase in VEGF, bFGF and GH.
... All these studies have been unified in a recent systematic review and meta-analysis where all exercise modalities (aerobic, resistance, or combined) are supported for their beneficial effects on people living with SZ (24). It seems that combining resistance and aerobic exercise enhances functional capacity more than aerobic exercise alone, due to different molecular and metabolic pathways, which could generate a "general adaptation profile" in untrained people (25). Furthermore, minimizing overall exercise volume in both types of exercise, including cycling as aerobic exercise as opposed to running, could contradict the "muscle interference" hypothesis (26,27). ...
Introduction:
Given the health benefits and the role of exercise as an anti-inflammatory adjuvant program, this study aimed to determine the effectiveness of a combined exercise program on cardiorespiratory fitness (CRF), body composition, and biochemical levels in adults with schizophrenia (SZ) characterized at baseline as metabolically unhealthy overweight with low CRF.
Methods:
Participants diagnosed with SZ (n = 112, 41.3 ± 10.4 yr, 28.7% women) were randomly assigned into a Treatment-As-Usual (TAU) control group (n = 53) or a supervised exercise group (n = 59, 3 days/week). Each combined exercise session consisted of both a low-volume high-intensity interval training (less than 10 min of high-intensity time per session) and a resistance circuit-training program. All variables were assessed pre-and post-intervention (20 weeks). For the assessment of CRF, a peak cardiopulmonary exercise test on a cycle ergometer was used.
Results:
Following the intervention, participants from the exercise group (n = 51) showed increases in CRF (P < 0.001) through peak oxygen uptake (L·min-1; Δ = 17.6%; mL·kg.1·min-1, Δ = 19.6%) and the metabolic equivalent of task (Δ = 19%), with no significant changes (P > 0.05) in body composition and biochemical variables. However, the TAU group (n = 38) did not show any significant change in the study variables (P > 0.05). Between-group significant differences (P ≤ 0.05) were observed in CRF, first ventilatory threshold, and heart rate peak after the intervention period favoring the exercise group.
Conclusions:
This study demonstrated that a supervised combined exercise program in people with SZ helps to maintain body composition values and improve CRF levels. This could lead to an important clinical change in the characterization from metabolically unhealthy overweight to a metabolically healthy overweight population. Hence, exercise should be considered a co-adjuvant program in the treatment of the SZ population.
... The CE protocol typically combines CMIE with RE within the same training session [116]. CE has shown benefits in glycaemic control (both fasting glycaemia and HbA1c levels) and body composition in patients with T2DM, and it has been found to induce positive effects on oxidative stress parameters [117]. ...
Oxidative stress is a critical factor in the pathogenesis and progression of diabetes and its associated complications. The imbalance between reactive oxygen species (ROS) production and the body’s antioxidant defence mechanisms leads to cellular damage and dysfunction. In diabetes, chronic hyperglycaemia and mitochondrial dysfunction contribute to increased ROS production, further exacerbating oxidative stress. This oxidative burden adversely affects various aspects of diabetes, including impaired beta-cell function and insulin resistance, leading to disrupted glucose regulation. Additionally, oxidative stress-induced damage to blood vessels and impaired endothelial function contribute to the development of diabetic vascular complications such as retinopathy, nephropathy, and cardiovascular diseases. Moreover, organs and tissues throughout the body, including the kidneys, nerves, and eyes, are vulnerable to oxidative stress, resulting in diabetic nephropathy, neuropathy, and retinopathy. Strategies to mitigate oxidative stress in diabetes include antioxidant therapy, lifestyle modifications, and effective management of hyperglycaemia. However, further research is necessary to comprehensively understand the underlying mechanisms of oxidative stress in diabetes and to evaluate the efficacy of antioxidant interventions in preventing and treating diabetic complications. By addressing oxidative stress, it might be possible to alleviate the burden of diabetes and improve patient outcomes.
... Typically, the specificity of the morphological and functional adaptations obtained by skeletal muscle depend on the implemented training modality [47]. Resistance training upregulates anabolic processes that ultimately translate to the chronic outcomes of muscle hypertrophy and strength gain [48]. ...
Blood flow-restricted exercise is currently used as a low-intensity time-efficient approach to reap many of the benefits of typical high-intensity training. Evidence continues to lend support to the notion that even highly trained individuals, such as athletes, still benefit from this mode of training. Both resistance and endurance exercise may be combined with blood flow restriction to provide a spectrum of adaptations in skeletal muscle, spanning from myofibrillar to mitochondrial adjustments. Such diverse adaptations would benefit both muscular strength and endurance qualities concurrently, which are demanded in athletic performance, most notably in team sports. Moreover, recent work indicates that when traditional high-load resistance training is supplemented with low-load, blood flow-restricted exercise, either in the same session or as a separate training block in a periodised programme, a synergistic and complementary effect on training adaptations may occur. Transient reductions in mechanical loading of tissues afforded by low-load, blood flow-restricted exercise may also serve a purpose during de-loading, tapering or rehabilitation of musculoskeletal injury. This narrative review aims to expand on the current scientific and practical understanding of how blood flow restriction methods may be applied by coaches and practitioners to enhance current athletic development models.
Future Soldier Fitness and Conditioning.
Physiological Demands of Changing War Conditions on the Battlefield and Contemporary Approaches in Physical Readiness Training of Soldiers
Resistance training (RT) triggers diverse morphological and physiological adaptations that are broadly considered beneficial for performance enhancement as well as injury risk reduction. Some athletes and coaches therefore engage in, or prescribe, substantial amounts of RT under the assumption that continued increments in maximal strength capacity and/or muscle mass will lead to improved sports performance. In contrast, others employ minimal or no RT under the assumption that RT may impair endurance or sprint performances. However, the morphological and physiological adaptations by which RT might impair physical performance, the likelihood of these being evoked, and the training program specifications that might promote such impairments, remain largely undefined. Here, we discuss how selected adaptations to RT may enhance or impair speed and endurance performances while also addressing the RT program variables under which these adaptations are likely to occur. Specifically, we argue that while some myofibrillar (muscle) hypertrophy can be beneficial for increasing maximum strength, substantial hypertrophy can lead to macro- and microscopic adaptations such as increases in body (or limb) mass and internal moment arms that might, under some conditions, impair both sprint and endurance performances. Further, we discuss how changes in muscle architecture, fiber typology, microscopic muscle structure, and intra- and intermuscular coordination with RT may maximize speed at the expense of endurance, or maximize strength at the expense of speed. The beneficial effect of RT for sprint and endurance sports can be further improved by considering the adaptive trade-offs and practical implications discussed in this review.
Graphical abstract
Background: Type 2 diabetes mellitus (T2DM) often leads to cardiac autonomic neuropathy (CAN), a severe complication affecting cardiovascular health. Exercise training is a proven intervention for improving metabolic control and cardiovascular health in T2DM, but the effects of concurrent exercise training (CET), combining aerobic and resistance exercises, on CAN are not fully understood. Objective: This randomized controlled trial investigates the impact of a structured CET program on cardiac autonomic modulation, metabolic profile, body composition, cardiorespiratory fitness (CRF), and quality of life (QoL) in individuals with T2DM and CAN. Methods: A total of 96 participants, aged 35–70 years, with T2DM and CAN, were randomized into CET (n = 48) and control (n = 48) groups. The CET group engaged in combined aerobic and resistance training three times per week for 13 weeks, while the control group received standard care. Primary outcomes included heart rate variability (HRV) and heart rate recovery (HRR). Secondary outcomes were metabolic profile, body composition, CRF, and QoL, which were assessed using standardized protocols and validated questionnaires. The trial was registered with the Clinical Trials Registry—India (CTRI/2021/09/036711). Results: Significant improvements were noted in the CET group compared to controls. HRV metrics (SDNN, RMSSD, pNN50, TP, LF power, HF power, and LF/HF ratio) and HRR metrics (HRR30s, HRR1, HRR2, and HRR3) all showed significant enhancements (p < 0.01). The CET group also exhibited substantial reductions in fasting blood glucose, postprandial blood glucose, HbA1c, waist circumference, hip circumference, and percentage body fat (p < 0.01). Improvements were observed in lipid profile markers and CRF (VO2max) (p < 0.01). QoL scores improved significantly in the CET group as per the ADDQoL-19 (p < 0.01). Conclusions: CET significantly enhances cardiac autonomic modulation, metabolic profile, body composition, CRF, and QoL in individuals with T2DM and CAN. These findings support the integration of CET into standard T2DM management to improve clinical outcomes and QoL. Further research is needed to explore the long-term benefits and broader applicability of CET in diverse diabetic populations.
Background
Many sports require maximal strength and endurance performance. Concurrent strength and endurance training can lead to suboptimal training adaptations. However, how adaptations differ between males and females is currently unknown. Additionally, current training status may affect training adaptations.
Objective
We aimed to assess sex-specific differences in adaptations in strength, power, muscle hypertrophy, and maximal oxygen consumption (V˙O2max) to concurrent strength and endurance training in healthy adults. Second, we investigated how training adaptations are influenced by strength and endurance training status.
Methods
A systematic review and meta-analysis was conducted according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, and a Cochrane risk of bias was evaluated. ISI Web of science, PubMed/MEDLINE, and SPORTDiscus databases were searched using the following inclusion criteria: healthy adults aged 18–50 years, intervention period of ≥ 4 weeks, and outcome measures were defined as upper- and lower-body strength, power, hypertrophy, and/or V˙O2max. A meta-analysis was performed using a random-effects model and reported in standardized mean differences.
Results
In total, 59 studies with 1346 participants were included. Concurrent training showed blunted lower-body strength adaptations in males, but not in females (male: − 0.43, 95% confidence interval [− 0.64 to − 0.22], female: 0.08 [− 0.34 to 0.49], group difference: P = 0.03). No sex differences were observed for changes in upper-body strength (P = 0.67), power (P = 0.37), or V˙O2max (P = 0.13). Data on muscle hypertrophy were insufficient to draw any conclusions. For training status, untrained but not trained or highly trained endurance athletes displayed lower V˙O2max gains with concurrent training (P = 0.04). For other outcomes, no differences were found between untrained and trained individuals, both for strength and endurance training status.
Conclusions
Concurrent training results in small interference for lower-body strength adaptations in males, but not in females. Untrained, but not trained or highly trained endurance athletes demonstrated impaired improvements in V˙O2max following concurrent training. More studies on females and highly strength-trained and endurance-trained athletes are warranted.
Clinical Trial Registration
PROSPERO: CRD42022370894.
Objective: To investigate the effects of concurrent training with different sequences on improving strength and endurance performance and the underlying molecular biological mechanisms.
Methods: Using the literature method, reading and summarizing the relevant literature, Starting from the effect of concurrent training with different sequences on improving strength and endurance, and attempting to explore the deep mechanism from the neuromuscular and molecular biological adaptation, and putting forward the influencing factors of the concurrent training effects with a different sequence. The results showed that most studies have confirmed that the correlation between endurance improvement and training sequence is insignificant. However, the "interference effect" of different training sequences on strength is a matter of debate. The endurance-strength training model is more conducive to skeletal muscle protein synthesis, promoting skeletal muscle hypertrophy and maximal strength; the strength-endurance training sequence is more likely to result in improved neuroadaptations and relative strength and explosive power output.
Suggestion: Rationalizing the training sequence based on training goals and individual subject differences; when the endurance-strength training model is selected, an interval of more than 3 hours is recommended to prevent acute interferences between the molecules.
Hippocrates wrote in 1931 that “eating alone will not keep a man well; he must also take exercise.” Since then, the impact of these two concepts on healthy life has never changed.Exercise is a very powerful tool, even medicine, in reducing harmful effects of chronic diseases and mortality rates, as well as in treating and preventing chronic diseases. There is a linear relationship between activity level and health status. People who lead an active and fit lifestyle live longer and healthier. In contrast, physical inactivity has a mind-boggling array of detrimental effects on health. Sedentary people are affected by the chronic disease early and die at a younger age as they do not adapt exercise/sports to their lives. This relationship between illness and a sedentary lifestyle affects all age groups, albeit in varying degrees: children, adults, and the elderly. Current studies show that people with active lifestyles are much healthier. It would not be wrong to say that inactivity, a problem that can be solved by movement, is the biggest public health problem in this era.In this section, the description, types, and prescription of the exercise that should be done regularly both in illness and health will be explained.KeywordsExerciseExercise typesExercise trainingExercise prescription
Reports concerning the effect of endurance exercise on the anabolic response to strength
training have been contradictory. This study re-investigated this issue, focusing on training
effects on indicators of protein synthesis and degradation. Two groups of male subjects performed
7 weeks of resistance exercise alone (R; n = 7) or in combination with preceding
endurance exercise, including both continuous and interval cycling (ER; n = 9). Muscle biopsies
were taken before and after the training period. Similar increases in leg-press 1 repetition
maximum (30%; P<0.05) were observed in both groups, whereas maximal oxygen
uptake was elevated (8%; P<0.05) only in the ER group. The ER training enlarged the
areas of both type I and type II fibers, whereas the R protocol increased only the type II
fibers. The mean fiber area increased by 28% (P<0.05) in the ER group, whereas no significant
increase was observed in the R group. Moreover, expression of Akt and mTOR protein
was enhanced in the ER group, whereas only the level of mTOR was elevated following R
training. Training-induced alterations in the levels of both Akt and mTOR protein were correlated
to changes in type I fiber area (r = 0.55–0.61, P<0.05), as well as mean fiber area (r =
0.55–0.61, P<0.05), reflecting the important role played by these proteins in connection with
muscle hypertrophy. Both training regimes reduced the level of MAFbx protein (P<0.05)
and tended to elevate that of MuRF-1. The present findings indicate that the larger hypertrophy
observed in the ER group is due more to pronounced stimulation of anabolic rather than
inhibition of catabolic processes.
Introduction
The current study sought to explore the incidence of nonresponders for maximal or submaximal performance following a variety of sprint interval training (SIT) protocols. Data from 63 young adults from 5 previously published studies were utilized in the current analysis. Nonresponders were identified using 2 times the typical error (TE) of measurement for peak oxygen uptake (2 × TE = 1.74 mL/(kg·min)), lactate threshold (2 × TE = 15.7 W), or 500 kcal time-to-completion (TTC; 2 × TE = 306 s) trial. TE was determined on separate groups of participants by calculating the test–retest variance for each outcome. The overall rate of nonresponders for peak oxygen uptake across all participants studied was 22% (14/63) with 4 adverse responders observed. No nonresponders for peak oxygen uptake were observed in studies where participants trained 4 times per week (n = 18), while higher rates were observed in most studies requiring training 3 times per week (30%–50%; n = 45). A nonresponse rate of 44% (8/18) and 50% (11/22) was observed for the TTC test and lactate threshold, respectively. No significant correlations were observed between the changes in peak oxygen uptake and TTC (r = 0.014; p = 0.96) or lactate threshold (r = 0.17; p = 0.44). The current analysis demonstrates a significant incidence of nonresponders for peak oxygen uptake and heterogeneity in the individual patterns of response following SIT. Additionally, these data support the importance of training dose and suggest that the incidence of nonresponse may be mitigated by utilizing the optimal dose of SIT.
Exercise is essential in regulating energy metabolism and whole-body insulin sensitivity. To explore the exercise signaling network, we undertook a global analysis of protein phosphorylation in human skeletal muscle biopsies from untrained healthy males before and after a single high-intensity exercise bout, revealing 1,004 unique exercise-regulated phosphosites on 562 proteins. These included substrates of known exercise-regulated kinases (AMPK, PKA, CaMK, MAPK, mTOR), yet the majority of kinases and substrate phosphosites have not previously been implicated in exercise signaling. Given the importance of AMPK in exercise-regulated metabolism, we performed a targeted in vitro AMPK screen and employed machine learning to predict exercise-regulated AMPK substrates. We validated eight predicted AMPK substrates, including AKAP1, using targeted phosphoproteomics. Functional characterization revealed an undescribed role for AMPK-dependent phosphorylation of AKAP1 in mitochondrial respiration. These data expose the unexplored complexity of acute exercise signaling and provide insights into the role of AMPK in mitochondrial biochemistry.
Satellite cells are the major myogenic stem cells residing inside skeletal muscle and are indispensable for muscle regeneration. Satellite cells remain largely quiescent, but are rapidly activated in response to muscle injury, and the derived myogenic cells then fuse to repair damaged muscle fibers or form new muscle fibers. However, mechanisms eliciting metabolic activation, an inseparable step for satellite cell activation following muscle injury, have not been defined. We found that a non-canonical Sonic Hedgehog (Shh) pathway is rapidly activated in response to muscle injury, which activates AMPK and induces a Warburg-like glycolysis in satellite cells. AMPKα1 is the dominant AMPKα isoform expressed in satellite cells and AMPKα1 deficiency in satellite cells impairs their activation and myogenic differentiation during muscle regeneration. Drugs activating non-canonical Shh promote proliferation of satellite cells, which is abolished due to satellite cell-specific AMPKα1 knockout. Taken together, AMPKα1 is a critical mediator linking non-canonical Shh pathway to Warburg-like glycolysis in satellite cells, which is required for satellite activation and muscle regeneration.
Proteins of the peroxisome proliferator-activated receptor γ (PPARγ) coactivator 1 (PGC-1) family of transcriptional coactivators coordinate physiological adaptations in many tissues, usually in response to demands for higher nutrient and energy supply. Of the founding members of the family, PGC-1α (also known as PPARGC1A) is the most highly regulated gene, using multiple promoters and alternative splicing to produce a growing number of coactivator variants. PGC-1α promoters are selectively active in distinct tissues in response to specific stimuli. To date, more than ten novel PGC-1α isoforms have been reported to be expressed from a novel promoter (PGC-1α-b, PGC-1α-c), to undergo alternative splicing (NT-PGC-1α) or both (PGC-1α2, PGC-1α3, PGC-1α4). The resulting proteins display differential regulation and tissue distribution and, most importantly, exert specific biological functions. In this review we discuss the structural and functional characteristics of the novel PGC-1α isoforms, aiming to provide an integrative view of this constantly expanding system of transcriptional coactivators.
Background: The ACTN3 gene may influence performance in team sports, in which sprint action and high-speed movements, regulated by the anaerobic energy system, are crucial to the ultimate success of a match. The aim of this study was to determine the association between the ACTN3 R577X (rs1815739) polymorphism and elite team sport athletic status in Italian male athletes.
Methods: We compared the genotype and allele frequency of the ACTN3 R577X polymorphism between team sport athletes (n = 75), endurance athletes (n = 40), sprint/power athletes (n = 64), and non-athletic healthy controls (n = 192) from Italy. Genomic DNA was collected using a buccal swab. Extraction was performed according to the manufacturer’s directions provided with a commercially available kit (Qiagen S.r.l., Milan, Italy).
Results: Team sport athletes showed a lower frequency of the 577RR genotype compared to the 577XX genotype than sprint/power athletes (p = 0.044). However, the ACTN3 R577X polymorphism was not associated with team sport athletic status compared to endurance athletes and non-athletic controls.
Conclusions: Our results agree with a recent large-scale study involving athletes from Spain, Poland, and Russia.
The ACTN3 R577X polymorphism was not associated with team sport athletic status compared to endurance athletes and non-athletic controls.
Muscle stem cells, termed satellite cells, are crucial for skeletal muscle growth and regeneration. In healthy adult muscle, satellite cells are quiescent but poised for activation. During muscle regeneration, activated satellite cells transiently re-enter the cell cycle to proliferate and subsequently exit the cell cycle to differentiate or self-renew. Recent studies have demonstrated that satellite cells are heterogeneous and that subpopulations of satellite stem cells are able to perform asymmetric divisions to generate myogenic progenitors or symmetric divisions to expand the satellite cell pool. Thus, a complex balance between extrinsic cues and intrinsic regulatory mechanisms is needed to tightly control satellite cell cycle progression and cell fate determination. Defects in satellite cell regulation or in their niche, as observed in degenerative conditions such as aging, can impair muscle regeneration. Here, we review recent discoveries of the intrinsic and extrinsic factors that regulate satellite cell behaviour in regenerating and degenerating muscles.
© 2015. Published by The Company of Biologists Ltd.
Background: The ACTN3 gene may influence performance in team sports, in which sprint action and high-speed movements, regulated by the anaerobic energy system, are crucial to the ultimate success of a match. The aim of this study was to determine the association between the ACTN3 R577X (rs1815739) polymorphism and elite team sport athletic status in Italian male athletes.
Methods: We compared the genotype and allele frequency of the ACTN3 R577X polymorphism between team sport athletes (n = 75), endurance athletes (n = 40), sprint/power athletes (n = 64), and non-athletic healthy controls (n = 192) from Italy. Genomic DNA was collected using a buccal swab. Extraction was performed according to the manufacturer’s directions provided with a commercially available kit (Qiagen S.r.l., Milan, Italy).
Results: Team sport athletes showed a lower frequency of the 577RR genotype compared to the 577XX genotype than sprint/power athletes (p = 0.044). However, the ACTN3 R577X polymorphism was not associated with team sport athletic status compared to endurance athletes and non-athletic controls.
Conclusions: Our results agree with a recent large-scale study involving athletes from Spain, Poland, and Russia.
The ACTN3 R577X polymorphism was not associated with team sport athletic status compared to endurance athletes and non-athletic controls.
Significance
The work reported in this paper describes a previously unknown signaling pathway in skeletal muscle acting through G protein-coupled receptor 56-Galpha12/13. This discovery elucidates a previously unknown mechanism of muscle anabolism and gives another target of investigation for therapies against the loss of muscle mass seen with aging and various wasting diseases.
The extent of skeletal muscle hypertrophy in response to resistance training is highly variable in humans. The main objective of this study was to explain the nature of this variability. More specifically, we focused on the myogenic stem cell population, the satellite cell (SC) as a potential mediator of hypertrophy. Twenty-three males (aged 18-35 yrs) participated in 16 wk of progressive, whole body resistance training, resulting in changes of 7.9±1.6% (range of -1.9-24.7%) and 21.0±4.0% (range of -7.0 to 51.7%) in quadriceps volume and myofibre cross-sectional area (CSA), respectively. The SC response to a single bout of resistance exercise (80% 1RM), analyzed via immunofluorescent staining resulted in an expansion of type II fibre associated SC 72 h following exercise (pre: 11.3±0.9; 72 h: 14.8±1.4 SC/type II fibre; p<0.05). Training resulted in an expansion of the SC pool associated with type I (pre: 10.7±1.1; post: 12.1±1.2 SC/type I fibre; p<0.05) and type II fibres (pre: 11.3±0.9; post: 13.0±1.2 SC/type II fibre; p<0.05). Analysis of individual SC responses revealed a correlation between the relative change in type I associated SC 24 to 72 hours following an acute bout of resistance exercise and the percentage increase in quadriceps lean tissue mass assessed by MRI (r2 = 0.566, p = 0.012) and the relative change in type II associated SC following 16 weeks of resistance training and the percentage increase in quadriceps lean tissue mass assessed by MRI (r2 = 0.493, p = 0.027). Our results suggest that the SC response to resistance exercise is related to the extent of muscular hypertrophy induced by training.
Concurrent training is defined as simultaneously incorporating both resistance and endurance exercise within a periodized training regime. Despite the potential additive benefits of combining these divergent exercise modes with regards to disease prevention and athletic performance, current evidence suggests that this approach may attenuate gains in muscle mass, strength, and power compared with undertaking resistance training alone. This has been variously described as the interference effect or concurrent training effect. In recent years, understanding of the molecular mechanisms mediating training adaptation in skeletal muscle has emerged and provided potential mechanistic insight into the concurrent training effect. Although it appears that various molecular signaling responses induced in skeletal muscle by endurance exercise can inhibit pathways regulating protein synthesis and stimulate protein breakdown, human studies to date have not observed such molecular 'interference' following acute concurrent exercise that might explain compromised muscle hypertrophy following concurrent training. However, given the multitude of potential concurrent training variables and the limitations of existing evidence, the potential roles of individual training variables in acute and chronic interference are not fully elucidated. The present review explores current evidence for the molecular basis of the specificity of training adaptation and the concurrent interference phenomenon. Additionally, insights provided by molecular and performance-based concurrent training studies regarding the role of individual training variables (i.e., within-session exercise order, between-mode recovery, endurance training volume, intensity, and modality) in the concurrent interference effect are discussed, along with the limitations of our current understanding of this complex paradigm.
We sought to determine whether acute RE-induced gene expression is modified by RE training. We studied the expression patterns of a select group of genes following an acute bout of RE in naïve and hypertrophying muscle. Thirteen untrained subjects underwent supervised RE training for 12 weeks of the non-dominant arm and performed an acute bout of RE one week after the last bout of the training program (training + acute). The dominant arm was either unexercised (control) or subjected to the same acute exercise bout as the trained arm (acute RE). Following training, males (14.8% +/- 2.8%, p<0.05) and females (12.6% +/- 2.4%, p<0.05) underwent muscle hypertrophy with increases in dynamic strength in the trained arm (48.2% +/- 5.4% and 72.1 +/- 9.1%, p<0.01, respectively). RE training resulted in attenuated anabolic signaling as reflected by a reduction in rpS6 phosphorylation following acute RE. Changes in mRNA levels of genes involved in hypertrophic growth, protein degradation, angiogenesis and metabolism commonly expressed in both males and females was determined 4 hrs. following acute RE. We show that RE training can modify acute RE induced gene expression in a divergent and gene specific manner even for genes belonging to the same ontogeny. Changes in gene expression following acute RE are multidimensional, and may not necessarily reflect the actual adaptive response taking place during the training process. Thus RE training can selectively modify the acute response to RE precluding the use of gene expression as a "marker" of exercise induced adaptations.
As aerobic exercise (AE) may interfere with adaptations to resistance exercise (RE), this study explored acute and chronic responses to consecutive AE (~45 min cycling) and RE (4 x 7 maximal knee extensions), vs. RE only. Ten men performed acute unilateral AE+RE interspersed by 15 min recovery. The contralateral leg was subjected to RE. This exercise paradigm was then implemented in a 5-wk training program. Protein phosphorylation, gene expression and glycogen content were assessed in biopsies obtained from m. vastus lateralis of both legs immediately before and 3 h after acute RE. Quadricep muscle size and in vivo torque were measured, and muscle samples analyzed for citrate synthase activity and glycogen concentration, before and after training. Acute AE reduced glycogen content (32%; P < 0.05) and increased (P < 0.05) phosphorylation of AMPK (1.5-fold) and rpS6 (1.3-fold). Phosphorylation of p70S6K and 4E-BP1 remained unchanged. Myostatin gene expression was downregulated after acute AE+RE but not RE. Muscle size showed greater (P < 0.05) increase after AE+RE (6%) than RE (3%) training. Citrate synthase activity (18%) and endurance performance (22%) increased (P < 0.05) after AE+RE but not RE. While training increased (P < 0.05) in vivo muscle strength in both legs, normalized and concentric torque increased after RE only. Thus, AE activates AMPK, reduces glycogen stores, and impairs the progression of concentric force, yet muscle hypertrophic responses to chronic RE training appears not to be compromised.
Recently, a truncated peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) splice variant, PGC-1α4, that originates from the alternative promoter was shown to be induced by resistance exercise and to elicit muscle hypertrophy without coactivation of "classical" PGC-1α targets involved in mitochondrial biogenesis and angiogenesis. In order to test if distinct physiological adaptations are characterized by divergent induction of PGC-1α splice variants, we investigated the expression of truncated and nontruncated PGC-1α splice variants and PGC-1α transcripts originating from the alternative and the proximal promoter, in human skeletal muscle in response to endurance and resistance exercise. Both total PGC-1α and truncated PGC-1α mRNA expression were increased 2 h after endurance (P < 0.01) and resistance exercise (P < 0.01), with greater increases after endurance exercise (P < 0.05). Expression of nontruncated PGC-1α increased significantly in both exercise groups (P < 0.01 for both groups) without any significant differences between the groups. Both endurance and resistance exercise induced truncated as well as nontruncated PGC-1α transcripts from both the alternative and the proximal promoter. Further challenging the hypothesis that induction of distinct PGC-1α splice variants controls exercise adaptation, both nontruncated and truncated PGC-1α transcripts were induced in AICAR-treated human myotubes (P < 0.05). Thus, contrary to our hypothesis, resistance exercise did not specifically induce the truncated forms of PGC-1α. Induction of truncated PGC-1α splice variants does not appear to underlie distinct adaptations to resistance versus endurance exercise. Further studies on the existence of numerous splice variants originating from different promoters are needed.
5'AMP-activated protein kinase (AMPK) plays an important role as a negative regulator of skeletal muscle mass. However, the precise mechanism of AMPK-mediated regulation of muscle mass is not fully clarified. Heat shock proteins (HSPs), stress-induced molecular chaperones, are related with skeletal muscle adaptation, but the association between AMPK and HSPs in skeletal muscle hypertrophy is unknown. Thus, it was investigated whether AMPK regulates hypertrophy by mediating HSPs in C2C12 cells. The treatment with 5-aminoimidazole-4-carboxamide-1-β-D-ribonucleoside (AICAR), a potent stimulator of AMPK, decreased 72 kDa HSP (HSP72) expression. Whereas there were no changes in the expressions of 25 kDa HSP, 70 kDa heat shock cognate, and heat shock transcription factor 1 in myotubes. Protein content and diameter were less in the AICAR-treated myotubes compared to those without treatment. AICAR-induced suppression of myotube hypertrophy and HSP72 expression were attenuated in the siRNA-mediated AMPKα-knockdown myotubes. AICAR increased microRNA (miR)-1, a modulator of HSP72. And the increase of miR-1 was not induced in AMPKα-knockdown condition. Furthermore, siRNA-mediated HSP72-knockdown blocked AICAR-induced inhibition of myotube hypertrophy. AICAR up-regulated the gene expression of muscle Ring-finger 1 and this alteration was suppressed in either AMPKα- or HSP72-knockdown myotubes. The phosphorylation of p70 S6 kinase Thr(389) was down-regulated by AICAR, while this was attenuated in AMPKα-, but not HSP72-, knockdown myotubes. These results suggest that AMPK inhibits hypertrophy through, in part, a HSP72-associated mechanism via miR-1 and protein degradation pathways in skeletal muscle cells.
The interference effect attenuates strength and hypertrophic responses when strength and endurance training are conducted concurrently; however, the influence of training frequency on these responses remain unclear when varying ratios of concurrent strength and endurance training are performed. Therefore, the purpose of the study was to examine the strength, limb girth, and neuromuscular adaptations to varying ratios of concurrent strength and endurance training. Twenty-four men with > 2 years resistance training experience completed 6 weeks of 3 days per week of (a) strength training (ST), (b) concurrent strength and endurance training ratio 3:1(CT3), (c) concurrent strength and endurance training ratio 1:1(CT1), or (d) no training (CON) in an isolated limb model. Assessments of maximal voluntary contraction by means of isokinetic dynamometry leg extensions (maximum voluntary suppression [MVC]), limb girth, and neuromuscular responses through electromyography (EMG) were conducted at baseline, mid-intervention, and postintervention. After training, ST and CT3 conditions elicited greater MVC increases than CT1 and CON conditions (p ≤ 0.05). Strength training resulted in significantly greater increases in limb girth than both CT1 and CON conditions (p = 0.05 and 0.004, respectively). The CT3 induced significantly greater limb girth adaptations than CON condition (p = 0.04). No effect of time or intervention was observed for EMG (p > 0.05). In conclusion, greater frequencies of endurance training performed increased the magnitude of the interference response on strength and limb girth responses after 6 weeks of 3 days a week of training. Therefore, the frequency of endurance training should remain low if the primary focus of the training intervention is strength and hypertrophy.
Numerous reports of genetic associations with performance- and injury-related phenotypes have been published over the past three decades; these studies have employed primarily the candidate gene approach to identify genes that associate with elite performance or with variation in performance-and/or injury-related traits. Although generally with small effect sizes and heavily prone to type I statistic error, the number of candidate genetic variants that can potentially explain elite athletic status, injury predisposition, or indeed response to training will be much higher than that examined by numerous biotechnology companies. Priority should therefore be given to applying whole genome technology to sufficiently large study cohorts of world-class athletes with adequately measured phenotypes where it is possible to increase statistical power. Some of the elite athlete cohorts described in the literature might suffice, and collectively, these cohorts could be used for replication purposes. Genome-wide association studies are ongoing in some of these cohorts (i.e., Genathlete, Russian, Spanish, Japanese, United States, and Jamaican cohorts), and preliminary findings include the identification of one single nucleotide polymorphism (SNP; among more than a million SNPs analyzed) that associates with sprint performance in Japanese, American (i.e., African American), and Jamaican cohorts with a combined effect size of ~2.6 (P-value <5×10(-7)) and good concordance with endurance performance between select cohorts. Further replications of these signals in independent cohorts will be required, and any replicated SNPs will be taken forward for fine-mapping/targeted resequencing and functional studies to uncover the underlying biological mechanisms. Only after this lengthy and costly process will the true potential of genetic testing in sport be determined.
The effect of duration-matched concurrent exercise training (CET) (50% resistance (RET) and 50% endurance (EET) training) on physiological training outcomes in untrained middle-aged men remains to be elucidated. Forty-seven men (age, 48.1 ± 6.8 years; body mass index, 30.4 ± 4.1 kg·m⁻²) were randomized into 12-weeks of EET (40–60 min of cycling), RET (10 exercises; 3–4 sets × 8–10 repetitions), CET (50% serial completion of RET and EET), or control condition. The following were determined: intervention-based changes in fitness and strength; abdominal visceral adipose tissue (VAT), total body fat (TB-FM) and fat-free (TB-FFM) mass; plasma cytokines (C-reactive protein (CRP), tumor necrosis factor-α (TNFα) interleukin-6 (IL-6)); muscle protein content of p110α and glucose transporter 4 (GLUT4); mRNA expression of GLUT4, peroxisome proliferator-activated receptor-γ coactivator-1α−β, cytochrome c oxidase, hexokinase II, citrate synthase; oral glucose tolerance; and estimated insulin sensitivity. CET promoted commensurate improvements of aerobic capacity and muscular strength and reduced VAT and TB-FM equivalently to EET and RET (p < 0.05), yet only RET increased TB-FFM (p < 0.05). Although TNFα and IL-6 were reduced after all training interventions (p < 0.05), CRP remained unchanged (p > 0.05). EET reduced area under the curve for glucose, insulin, and C-peptide, whilst CET and RET respectively reduced insulin and C-peptide, and C-peptide only (p < 0.05). Notwithstanding increased insulin sensitivity index after all training interventions (p < 0.05), no change presented for GLUT4 or p110α total protein, or chronic mRNA expression of the studied mitochondrial genes (p > 0.05). In middle-aged men, 12 weeks of duration-matched CET promoted commensurate changes in fitness and strength, abdominal VAT, plasma cytokines and insulin sensitivity, and an equidistant glucose tolerance response to EET and RET; despite no change of measured muscle mechanisms associative to insulin action, glucose transport, and mitochondrial function.
The purpose of this study was to explore the possible role of muscle stem cells, also referred to as satellite cells (SCs), in adaptation and remodeling following a nonhypertrophic stimulus in humans. Muscle biopsies were obtained from the vastus lateralis of previously untrained women (n=15; age: 27±8 yr, BMI: 29±6 kg/m(2)) before and after 6 wk of aerobic interval training. The fiber type-specific SC response to training was analyzed using immunofluorescent microscopy of muscle cross sections. Following training, the number of SCs associated with fibers expressing myosin heavy-chain type I and II isoforms (hybrid fibers) increased (pre: 0.062±0.035 SC/hybrid fiber; post: 0.38±0.063 SC/hybrid fiber; P<0.01). In addition, there was a greater number of MyoD(+)/Pax7(-) SCs, indicative of differentiating SCs, associated with hybrid fibers (0.18±0.096 MyoD(+)/Pax7(-) SC/hybrid fiber) compared to type I (0.015±0.00615 MyoD(+)/Pax7(-) SC/type I fiber) or II (0.012±0.00454 MyoD(+)/Pax7(-) SC/type II fiber) fibers (P<0.05). There was also a training-induced increase in the number of hybrid fibers containing centrally located nuclei (15.1%) compared to either type I (3.4%) or II fibers (3.6%) (P<0.01). These data are consistent with the hypothesis that SCs contribute to the remodeling of muscle fibers even in the absence of hypertrophy.-Joanisse, S., Gillen, J. B., Bellamy, L. M., McKay, B. R., Tarnopolsky, M. A., Gibala, M. J., Parise, G. Evidence for the contribution of muscle stem cells to nonhypertrophic skeletal muscle remodeling in humans.
Here we report on the effect of combining endurance training with heavy or explosive strength training on endurance performance in endurance-trained runners and cyclists. Running economy is improved by performing combined endurance training with either heavy or explosive strength training. However, heavy strength training is recommended for improving cycling economy. Equivocal findings exist regarding the effects on power output or velocity at the lactate threshold. Concurrent endurance and heavy strength training can increase running speed and power output at VO2max (Vmax and Wmax , respectively) or time to exhaustion at Vmax and Wmax . Combining endurance training with either explosive or heavy strength training can improve running performance, while there is most compelling evidence of an additive effect on cycling performance when heavy strength training is used. It is suggested that the improved endurance performance may relate to delayed activation of less efficient type II fibers, improved neuromuscular efficiency, conversion of fast-twitch type IIX fibers into more fatigue-resistant type IIA fibers, or improved musculo-tendinous stiffness.
The ability of skeletal muscles to produce force at a high velocity, which is crucial for success in power and sprint performance, is strongly influenced by genetics and without the appropriate genetic make-up, an individual reduces his/her chances of becoming an exceptional power or sprinter athlete. Several genetic variants (i.e. polymorphisms) have been associated with elite power and sprint performance in the last few years and the current paradigm is that elite performance is a polygenic trait, with minor contributions of each variant to the unique athletic phenotype. The purpose of this review is to summarize the specific knowledge in the field of genetics and elite power performance, and to provide some future directions for research in this field. Of the polymorphisms associated with elite power and sprint performance, the α-actinin-3 R577X polymorphism provides the most consistent results. ACTN3 is the only gene that shows a genotype and performance association across multiple cohorts of elite power athletes, and this association is strongly supported by mechanistic data from an Actn3 knockout mouse model. The angiotensin-1 converting enzyme insertion/deletion polymorphism (ACE I/D, registered single nucleotide polymorphism [rs]4646994), angiotensinogen (AGT Met235Thr rs699), skeletal adenosine monophosphate deaminase (AMPD1) Gln(Q)12Ter(X) [also termed C34T, rs17602729], interleukin-6 (IL-6 -174 G/C, rs1800795), endothelial nitric oxide synthase 3 (NOS3 -786 T/C, rs2070744; and Glu298Asp, rs1799983), peroxisome proliferator-activated receptor-α (PPARA Intron 7 G/C, rs4253778), and mitochondrial uncoupling protein 2 (UCP2 Ala55Val, rs660339) polymorphisms have also been associated with elite power performance, but the findings are less consistent. In general, research into the genetics of athletic performance is limited by a small sample size in individual studies and the heterogeneity of study samples, often including athletes from multiple-difference sporting disciplines. In the future, large, homogeneous, strictly defined elite power athlete cohorts need to be established though multinational collaboration, so that meaningful genome-wide association studies can be performed. Such an approach would provide unbiased identification of potential genes that influence elite athletic performance.
The current dogma is that the muscle adaptation to resistance exercise is blunted when combined with endurance exercise. The suggested mechanism (based on rodent experiments) is that activation of adenosine-monophosphate-activated protein-kinase (AMPK) during endurance exercise impairs muscle growth through inhibition of the mechanistic-target-of-rapamycin-complex 1 (mTORC1). The purpose of this study was to investigate potential interference of endurance training on the signalling pathways of resistance training (mTORC1 - phosphorylation of ribosomal protein S6 kinase 1 (S6K1)) in human muscle. Ten healthy and moderately trained male subjects performed on two separate occasions either acute high intensity and high volume resistance exercise (leg press, R) or R followed by 30 min of cycling (RE). Muscle biopsies were collected before, 1 and 3h post resistance exercise. Phosphorylation of mTOR (Ser(2448)) increased 2-fold (p<0.05) and that of S6K1 (Thr(389)) 14-fold (p<0.05), with no difference between R and RE. Phosphorylation of eukaryotic elongation factor 2 (eEF2, Thr(56)) was reduced ~70% during recovery in both trials (p<0.05). An interesting finding was that phosphorylation of AMPK (Thr(172)) and acetyl-CoA carboxylase (ACC, Ser(79)) decreased ~30% and ~50%, respectively, 3h post exercise (p<0.05). Proliferator-activated receptor-γ-coactivator-1 (PGC-1α) mRNA increased more after RE (6.5-fold) than after R (4-fold) (RE vs. R: p< 0.01) and was the only gene expressed differently between trials. These data show that the signalling of muscle growth through the mTORC1-S6K1 axis after heavy resistance exercise is not inhibited by subsequent endurance exercise. It is also suggested that prior activation of mTORC1 signalling may repress subsequent phosphorylation of AMPK.
Physical activity and molecular ageing presumably interact to precipitate musculoskeletal decline in humans with age. Herein, we have delineated molecular networks for these two major components of sarcopenic risk using multiple independent clinical cohorts. We generated genome-wide transcript profiles from individuals (n = 44) who then undertook 20 weeks of supervised resistance-exercise training (RET). Expectedly, our subjects exhibited a marked range of hypertrophic responses (3% to +28%), and when applying Ingenuity Pathway Analysis (IPA) up-stream analysis to ∼580 genes that co-varied with gain in lean mass, we identified rapamycin (mTOR) signaling associating with growth (P = 1.4×10(-30)). Paradoxically, those displaying most hypertrophy exhibited an inhibited mTOR activation signature, including the striking down-regulation of 70 rRNAs. Differential analysis found networks mimicking developmental processes (activated all-trans-retinoic acid (ATRA, Z-score = 4.5; P = 6×10(-13)) and inhibited aryl-hydrocarbon receptor signaling (AhR, Z-score = -2.3; P = 3×10(-7))) with RET. Intriguingly, as ATRA and AhR gene-sets were also a feature of endurance exercise training (EET), they appear to represent "generic" physical activity responsive gene-networks. For age, we found that differential gene-expression methods do not produce consistent molecular differences between young versus old individuals. Instead, utilizing two independent cohorts (n = 45 and n = 52), with a continuum of subject ages (18-78 y), the first reproducible set of age-related transcripts in human muscle was identified. This analysis identified ∼500 genes highly enriched in post-transcriptional processes (P = 1×10(-6)) and with negligible links to the aforementioned generic exercise regulated gene-sets and some overlap with ribosomal genes. The RNA signatures from multiple compounds all targeting serotonin, DNA topoisomerase antagonism, and RXR activation were significantly related to the muscle age-related genes. Finally, a number of specific chromosomal loci, including 1q12 and 13q21, contributed by more than chance to the age-related gene list (P = 0.01-0.005), implying possible epigenetic events. We conclude that human muscle age-related molecular processes appear distinct from the processes regulated by those of physical activity.
Preservation of aerobic fitness and skeletal muscle strength through exercise training can ameliorate metabolic dysfunction and prevent chronic disease. These benefits are mediated in part by extensive metabolic and molecular remodeling of skeletal muscle by exercise. Aerobic and resistance exercise represent extremes on the exercise continuum and elicit markedly different training responses that are mediated by a complex interplay between a myriad of signaling pathways coupled to downstream regulators of transcription and translation. Here, we review the metabolic responses and molecular mechanisms that underpin the adaptatation of skeletal muscle to acute exercise and exercise training.