Acute Concurrent Exercise Improves Inhibitory Control Without Mediating the Role of Lactate: An Event-Related Potential Study

BACKGROUND

Concurrent exercise (CE), an emerging exercise modality characterized by sequential bouts of aerobic (AE) and resistance exercise (RE), has demonstrated acute benefits on executive functions (EFs) and neuroelectric P3 amplitude. However, the effect of acute CE on inhibitory control, a sub-component of EFs, and P3 amplitude remains inconclusive. Moreover, exploring the mechanisms underlying the effects of acute exercise on EFs contributes to scientific comprehension, with lactate recognized as a crucial candidate positively correlated with EFs. Therefore, this study aimed to determine the effects of acute CE on inhibitory control via behavioral and event-related potential approaches and to examine its potential mediational role on lactate.

METHODS

Seventy-eight adults (mean age = 22.95, SD = 1.75 years) were randomly assigned to either a CE, AE, or control (CON) group. Participants in the CE group engaged in 12-min of AE (40-59% of heart rate reserve [HRR]) coupled with 13-min of RE (1 set, with 75% of 10-repetition maximum, and 12 repetitions of 8 movements). The AE group participated in 25 min of AE (40-59% HRR). Prior to and following exercise onset, participants in both the CE and AE groups completed a 5-min warm-up and cool-down. Participants in the CON group read books for 35 min. Lactate concentrations were measured at timepoints of 0-, 17-, and 30-min relative to the treatment onset. Response time (RT) and accuracy in the Stroop test, as well as P3 amplitude, were assessed before and after the treatment.

RESULTS

The results revealed that both the CE and AE groups had significantly shorter RTs compared to the CON group, with no significant differences in accuracy among groups. A decrease in P3 amplitude was observed for the CE group compared to the AE and CON groups. The mediating effects of lactate between acute exercise and inhibitory control were insignificant.

CONCLUSIONS

The findings suggest that both CE and AE improve inhibitory control and CE potentially enhances the efficient allocation of attention resources. The lack of a significant mediating effect of lactate warrants further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT06370286. Registered 12 April 2024-Retrospectively registered, https://clinicaltrials.gov/study/NCT06370286 .

Optimizing concurrent training programs: A review on factors that enhance muscle strength

The purpose of this study is to explore the factors that should be considered when designing concurrent training programs to minimize the "interference effect." This study provides a comprehensive summary of various perspectives from existing studies on factors such as the ability level of the target group, the frequency and intensity of concurrent training, the order and interval time of resistance and endurance training, nutritional arrangements during training, and gender differences in concurrent training. The results of this study suggest that the emergence of the "interference effect" in concurrent training is influenced by several factors, with a particular emphasis on the adaptation status of muscle fitness when compared to resistance training alone. However, it is important to note that the current understanding of this theory remains somewhat ambiguous. The ability level of participants plays a crucial role in training adaptation and the specificity of post-training skeletal muscle molecular responses. Therefore, the participant's capacity level is likely a key determinant of the extent of the interference effect in concurrent training. In addition to training-related factors such as frequency, duration, intensity, volume, training sequence, recovery time, and nutritional intake, non-training-related variables, including the methodology used to assess various metrics, also significantly impact the design of concurrent training programs. These factors collectively influence the overall outcomes and provide insight into the extent of the "interference effect" in concurrent training. Understanding these aspects is essential for comprehending the phenomenon of the "interference effect" in concurrent training.

Effect of Strength and Endurance Training Sequence on Endurance Performance

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.

Perspectives on Concurrent Strength and Endurance Training in Healthy Adult Females: A Systematic Review

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.

Multicomponent Training and Optimal Dosing Strategies for Adults with Hypertension: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

(1) Background: Non-pharmacological interventions have demonstrated efficacy in the prevention, management, and control of hypertension. Multicomponent training confers a host of benefits to the general populace. The aim of this research was to assess the impact of multicomponent training on the blood pressure of adults with hypertension and ascertain the nature of the dose-response relationship. (2) Methods: This systematic review adhered to the PRISMA guidelines and was registered in PROSPERO. Eight studies were included, following a literature search across PubMed, Web of Science, Cochrane, and EBSCO. Randomized controlled trials implementing multicomponent training interventions on adults with hypertension were considered for inclusion. A quality assessment was performed using the PEDro scale, with a random-effects model utilized for all analyses. (3) Results: Multicomponent training yielded a significant reduction in systolic (MD = -10.40, p < 0.001) and diastolic (MD = -5.97, p < 0.001) blood pressure relative to the control group. Interventions lasting over 14 weeks with a minimum frequency of three sessions per week, each lasting 60 min, were deemed most effective. (4) Conclusion: An optimal training intensity was achieved with 30 min of aerobic exercise at 75% of the heart rate reserve, whereas sets of 10 repetitions at 75% of one repetition maximum produced the best outcomes in strength training.

Self-Rated Recovery and Mood Before and After Resistance Training and Muscle Microcurrent Application

Background

Resistance training (RT) can offer beneficial physiological and psychological effects. The regular continuation of this exercise can be accomplished by improving the recovery and mood after a workout. Frequency-specific microcurrent (microstimulation) might offer a solution here as it has been shown to improve physical injuries, mood state, and sleep. However, knowledge is lacking about the impact of microstimulation after RT on said parameters. The present study aimed to test the effects of RT and muscle-microstimulation on mood and physical recovery in healthy men after performing conventional deadlifts, which is a type of RT.

Methods

The study was conducted according to a single-blind, randomized, placebo-controlled, and two-way crossover study. Twenty participants naïve to microstimulation (MS) engaged in RT twice on separate days. They were randomized to receive MS on 1 day and no microstimulation (Sham-MS) on another day. Before and after the workout and after their treatment (MS or Sham-MS), participants self-rated their mood state and mental and physical exhaustion levels.

Results

Findings showed that MS increased the self-ratings of well-rested and sociable and, most importantly, reduced the feeling of exercise-induced exhaustion. There were no MS effects on ratings of feeling sad, happy, or exhausted, although the workout, independent of MS, negatively influenced the level of exhaustion.

Conclusion

The combination of enhanced sociableness, reduced fatigue, and exercise-induced exhaustion after a workout, followed by microstimulation, has important implications for professional sporters and nonprofessionals who try to get the best result after a workout. Future studies using a double-blind approach including different types of exercises, different durations of programs, and both sexes can shed more light on the full potential of microstimulation after a workout on mood state and exercise-induced exhaustion.

Acute Neuromuscular Response to Team Sports-specific Running, Resistance, and Concurrent Training: A Cross-over Study

PURPOSE

To examine the changes in muscle contractile function, voluntary activation, and muscle damage following lower limb resistance training (RT), intermittent sprint exercise and concurrent training (CT).

METHODS

Ten male, recreational team sport athletes with a history of RT participated in a randomised cross-over study involving an intermittent sprint protocol (ISP), lower limb RT and CT (ISP and RT separated by 1 h). Prior to (PRE), immediately post (POST), 24 h and 48 h following each exercise condition, quadriceps muscle activation, voluntary activation, muscle contractile function (evoked twitch responses), creatine kinase (CK), muscle soreness and POMS-fatigue were recorded.

RESULTS

Quadriceps contractile function was hampered in all conditions, with a significantly greater decline observed POST RT (58.4 ± 18.0%) and CT (54.8 ± 8.6%) compared to ISP (35.9 ± 10.7%; p < 0.05), recovering at 48 h following all exercise conditions. POMS-fatigue ratings increased at POST in all conditions with CT and ISP eliciting the greatest increase, returning to baseline 48 h following all exercise conditions. Quadriceps muscle soreness remained elevated from PRE at 48 h following all exercise conditions. No changes across time were observed for voluntary activation and quadriceps surface EMG amplitude following any exercise condition. The volume and load lifted in the RT session was unaffected by prior intermittent exercise (ISP) in CT.

CONCLUSION

RT impairs contractile function which is not exacerbated when performed 1 h following the ISP. Contractile function following all exercise conditions displayed the same recovery profile (48 h) despite the post-exercise decrement being smaller following the ISP compared to RT and CT. Prior intermittent sprint exercise does not negatively impact the volume of exercise performed in a lower limb RT session.

A 10-Week Block of Combined High-Intensity Endurance and Strength Training Produced Similar Changes in Dynamic Strength, Body Composition, and Serum Hormones in Women and Men

Purpose: To examine the potential sex differences in adaptations to combined endurance and strength training in recreationally endurance trained (eumenorrheic) women (n = 9) and men (n = 10).

Methods: Isometric (ISOM_max) and dynamic bilateral leg press (1RM), countermovement jump (CMJ), running performance (3,000 m time trial), lean mass and body fat % (LEAN and FAT% determined by dual X-ray absorptiometry) as well as serum testosterone and cortisol (TES and COR, respectively, measured using hormone-specific immunoassay kits) were examined before a control period and pre, mid, and post a supervised 10-week combined high-intensity interval endurance training (4 × 4 min intervals and 3 × 3 × 100 m repeated sprints) and mixed maximal and explosive strength training. No more than 2 weeks separated training and testing for either women or men and all women were tested in the early follicular phase of the menstrual cycle to minimize the possible influence of menstrual cycle phase on performance measures.

Results: Absolute and relative changes in 1RM, CMJ, 3,000 m, LEAN, and FAT% were similar between groups. The only statistically significant differences observed between groups were observed at post and included a larger Δ% increase in ISOM_max force in men and a relatively greater Δ% decrease in serum TES in women.

Conclusion: Women and men can achieve similar relative adaptations in dynamic maximal strength and CMJ as well as endurance performance gains and body composition over the same high-intensity 10-week combined program, although relative adaptations in TES may differ.

Order of same-day concurrent training influences some indices of power development, but not strength, lean mass, or aerobic fitness in healthy, moderately-active men after 9 weeks of training

Background

The importance of concurrent exercise order for improving endurance and resistance adaptations remains unclear, particularly when sessions are performed a few hours apart. We investigated the effects of concurrent training (in alternate orders, separated by ~3 hours) on endurance and resistance training adaptations, compared to resistance-only training.

Materials and methods

Twenty-nine healthy, moderately-active men (mean ± SD; age 24.5 ± 4.7 y; body mass 74.9 ± 10.8 kg; height 179.7 ± 6.5 cm) performed either resistance-only training (RT, n = 9), or same-day concurrent training whereby high-intensity interval training was performed either 3 hours before (HIIT+RT, n = 10) or after resistance training (RT+HIIT, n = 10), for 3 d^.wk^-1 over 9 weeks. Training-induced changes in leg press 1-repetition maximal (1-RM) strength, countermovement jump (CMJ) performance, body composition, peak oxygen uptake (V˙O2peak), aerobic power (W˙peak), and lactate threshold (W˙LT) were assessed before, and after both 5 and 9 weeks of training.

Results

After 9 weeks, all training groups increased leg press 1-RM (~24–28%) and total lean mass (~3-4%), with no clear differences between groups. Both concurrent groups elicited similar small-to-moderate improvements in all markers of aerobic fitness (V˙O2peak ~8–9%; W˙LT ~16-20%; W˙peak ~14-15%). RT improved CMJ displacement (mean ± SD, 5.3 ± 6.3%), velocity (2.2 ± 2.7%), force (absolute: 10.1 ± 10.1%), and power (absolute: 9.8 ± 7.6%; relative: 6.0 ± 6.6%). HIIT+RT elicited comparable improvements in CMJ velocity only (2.2 ± 2.7%). Compared to RT, RT+HIIT attenuated CMJ displacement (mean difference ± 90%CI, -5.1 ± 4.3%), force (absolute: -8.2 ± 7.1%) and power (absolute: -6.0 ± 4.7%). Only RT+HIIT reduced absolute fat mass (mean ± SD, -11.0 ± 11.7%).

Conclusions

In moderately-active males, concurrent training, regardless of the exercise order, presents a viable strategy to improve lower-body maximal strength and total lean mass comparably to resistance-only training, whilst also improving indices of aerobic fitness. However, improvements in CMJ displacement, force, and power were attenuated when RT was performed before HIIT, and as such, exercise order may be an important consideration when designing training programs in which the goal is to improve lower-body power.

Longitudinal Study of Body Composition and Energy Expenditure in Overweight or Obese Young Adults

The aim of this study was to compare the effects of an aerobic training program with a strength training program on body composition and energy expenditure in overweight or obese (29.06 ± 3.49 kg/m²) young adults (21.96 ± 1.90 years). Subjects (N = 109) were randomly assigned to one of three groups: a control group (CG), an aerobic training (AT) group and a strength training (ST) group. Training took place over twelve weeks comprising three sessions per week with each session lasting 60 to 90 minutes. Before and after the program, weight, height, body mass index, lean mass percentage and fat mass percentage were evaluated. In addition, The International Physical Activity Questionnaire-Short Form (IPAQ-SF) was used to estimate energy expenditure. The results of both aerobic training and strength training produced statistically significant improvements in weight (AT-CG = −2.892 kg; ST-CG = −2.986 kg); BMI (AT-CG = −1.075 kg/m²; ST-CG = −1.118 kg/m²); total body fat (AT-CG = −1529.172 g; ST-CG = −763.815); and total body fat percentage (AT-CG = −1.421%; AT-ST = −0.855%). These two exercise prescription models were therefore useful in reducing overweight and obesity, which could have an impact on improving the health and quality of life of individuals with these characteristics.

A Brief Review on Concurrent Training: From Laboratory to the Field

The majority of sports rely on concurrent training (CT; e.g., the simultaneous training of strength and endurance). However, a phenomenon called “Concurrent training effect” (CTE), which is a compromise in adaptation resulting from concurrent training, appears to be mostly affected by the interference of the molecular pathways of the underlying adaptations from each type of training segments. Until now, it seems that the volume, intensity, type, frequency of endurance training, as well as the training history and background strongly affect the CTE. High volume, moderate, continuous and frequent endurance training, are thought to negatively affect the resistance training-induced adaptations, probably by inhibition of the Protein kinase B—mammalian target of rapamycin pathway activation, of the adenosine monophosphate-activated protein kinase (AMPK). In contrast, it seems that short bouts of high-intensity interval training (HIIT) or sprint interval training (SIT) minimize the negative effects of concurrent training. This is particularly the case when HIIT and SIT incorporated in cycling have even lower or even no negative effects, while they provide at least the same metabolic adaptations, probably through the peroxisome proliferator-activated receptor-γ coactivator (PGC-1a) pathway. However, significant questions about the molecular events underlying the CTE remain unanswered.

The Role of Intra-Session Exercise Sequence in the Interference Effect: A Systematic Review with Meta-Analysis

BACKGROUND

There is a necessity for numerous sports to develop strength and aerobic capacity simultaneously, placing a significant demand upon the practice of effective concurrent training methods. Concurrent training requires the athlete to perform both resistance and endurance exercise within a training plan. This training paradigm has been associated with an 'interference effect', with attenuated strength adaptation in comparison to that following isolated resistance training. The effectiveness of the training programme rests on the intricacies of manipulating acute training variables, such as exercise sequence. The research, in the most part, does not provide a clarity of message as to whether intra-session exercise sequence has the potential to exacerbate or mitigate the interference effect associated with concurrent training methods.

OBJECTIVE

The aim of the systematic review and meta-analysis was to assess whether intra-session concurrent exercise sequence modifies strength-based outcomes associated with the interference effect.

METHODS

Ten studies were identified from a systematic review of the literature for the outcomes of lower-body dynamic and static strength, lower-body hypertrophy, maximal aerobic capacity and body fat percentage. Each study examined the effect of intra-session exercise sequence on the specified outcomes, across a prolonged (≥5 weeks) concurrent training programme in healthy adults.

RESULTS

Analysis of pooled data indicated that resistance-endurance exercise sequence had a positive effect for lower-body dynamic strength, in comparison to the alternate sequence (weighted mean difference, 6.91% change; 95% confidence interval 1.96, 11.87 change; p = 0.006), with no effect of exercise sequence for lower-body muscle hypertrophy (weighted mean difference, 1.15% change; 95% confidence interval -1.56, 3.87 change; p = 0.40), lower-body static strength (weighted mean difference, -0.04% change; 95% confidence interval -3.19, 3.11 change; p = 0.98), or the remaining outcomes of maximal aerobic capacity and body fat percentage (p > 0.05).

CONCLUSION

These results indicate that the practice of concurrent training with a resistance followed by an endurance exercise order is beneficial for the outcome of lower-body dynamic strength, while alternating the order of stimuli offers no benefit for training outcomes associated with the interference effect.

Functional physical training improves women's military occupational performance

The U.S. Armed Forces have recently approved full integration of women into combat roles. Physical fitness demands for executing Military Occupational Specialties (MOS) are substantial; thus lifting and load carriage capability improvements are desirable.

OBJECTIVES

To determine if a specially-designed physical conditioning program could lessen the gap between the performance of male and female Soldiers in lifting and load carriage and thereby enable women to meet the requirements of most, if not all, Army MOSs.

METHODS

Forty women participated in a 24-week physical training program, which included resistance training, long-distance running, backpacking, and specialized drills. Pre- and post-tests of occupational and physical performance measures were conducted before and after training. Repeated measures analysis of variance were used to determine statistically significant differences among the pre-, mid- and posttests.

RESULTS

Women increased maximal occupational lifting strength 12-20 kg, added 9-34 repetitions in lifting endurance, increased 0.23 m in jumping performance, added 46 repetitions in local muscular endurance, and decreased load carriage for time by 3.7-8.6 min. Women scored within 82-94% of untrained male scores for aerobic capacity and muscular endurance after training.

CONCLUSION

Women's ability to perform physically-demanding military occupational tasks was significantly improved following 6 months of concurrent training, with emphasis on load carriage and lifting. The percentage of women that qualified for current "heavy" and "very heavy" MOSs was initially 24%, but increased to 78% after training. A resistance training program of 6+ months can adequately prepare women for "heavy" to "very heavy" MOS's.

Fitness, body composition and blood lipids following 3 concurrent strength and endurance training modes

This study investigated changes in physical fitness, body composition, and blood lipid profile following 24 weeks of 3 volume-equated concurrent strength and endurance training protocols. Physically active, healthy male and female participants (aged 18–40 years) performed strength and endurance sessions on different days (DD; men, n = 21; women, n = 18) or in the same session with endurance preceding strength (ES; men, n = 16; women, n = 15) or vice versa (SE; men, n = 18; women, n = 14). The training volume was matched in all groups. Maximal leg press strength (1-repetition maximum (1RM)) and endurance performance (maximal oxygen consumption during cycling), body composition (dual-energy X-ray absorptiometry), and blood lipids were measured. 1RM and maximal oxygen consumption increased in all groups in men (12%–17%, p < 0.001; and 7%–18%, p < 0.05–0.001, respectively) and women (13%–21%, p < 0.01–0.001; and 10%–25%, p < 0.01–0.001, respectively). Maximal oxygen consumption increased more in DD vs. ES and SE both in men (p = 0.003–0.008) and women (p = 0.008–0.009). Total body lean mass increased in all groups (3%–5%, p < 0.01–0.001). Only DD led to decreased total body fat (men, −14% ± 15%, p < 0.001; women, −13% ± 14%, p = 0.009) and abdominal-region fat (men, −18% ± 14%, p = 0.003; women, −17% ± 15%, p = 0.003). Changes in blood lipids were correlated with changes in abdominal-region fat in the entire group (r = 0.283, p = 0.005) and in DD (r = 0.550, p = 0.001). In conclusion, all modes resulted in increased physical fitness and lean mass, while only DD led to decreases in fat mass. Same-session SE and ES combined training is effective in improving physical fitness while volume-equated, but more frequent DD training may be more suitable for optimizing body composition and may be possibly useful in early prevention of cardiovascular and metabolic diseases.

Cardiorespiratory Adaptations during Concurrent Aerobic and Strength Training in Men and Women

This study investigated the effects of endurance followed by strength training (ES, men n = 16; women n = 15), the reverse exercise order (SE, men n = 18, women n = 13) and concurrent endurance and strength training performed on alternating days (AD, men n = 21, women n = 18) on cardiorespiratory parameters. Peak oxygen consumption ([Formula: see text]O2peak) and oxygen consumption at sub-maximal power outputs ([Formula: see text]O2submax) of 50 to 175 Watts in men and 50 to 125 Watts in women were assessed during an incremental cycling test both before and after 24 weeks of training. Increases in [Formula: see text]O2peak in both men and women were statistically larger in AD (18±9% and 25±11%) compared to ES (7±9% and 12±12%, p = 0.002 and 0.009, respectively) and SE (7±9% and 10±8%, p = 0.005 and 0.008, respectively). No statistical group interaction was observed for [Formula: see text]O2submax in men, but in women [Formula: see text]O2submax was statistically lower at week 24 in ES compared to AD at 75 W (-2±6% vs. +3±6%, p = 0.027) and 125 W (-4±5% vs. +2±5%, p = 0.010). These findings indicate that endurance and strength training performed on alternating days may optimize the adaptations in [Formula: see text]O2peak in both sexes, while performing ES training in women may optimize cardiorespiratory fitness at sub-maximal power outputs.