Acute hormonal and force responses to combined strength and endurance loadings in men and women: the "order effect"

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.

Caffeine ingestion attenuates diurnal variation of lower-body ballistic performance in resistance-trained women

ABSTRACTThe present study investigates the effect of an acute intake of caffeine on the diurnal variation of neuromuscular performance in resistance-trained women. A total of 15 resistance-trained women participated in the current triple-blind, placebo-controlled, crossover experimental study. We assessed neuromuscular performance (i.e. ballistic (countermovement jump [CMJ] height and bench press throw [BPT] peak velocity), maximal strength (squat and bench press [BP] one-repetition maximum [1RM]), and strength-endurance [average velocity of the set during squat and number of repetitions-to-failure in BP]) four times at within 7 days. The participants ingested an acute dose of caffeine (3 mg/kg) or a placebo at 9-11 am and/or 17-19 pm. CMJ height (P = .016) and BP peak velocity (P = .012) were higher in the afternoon than in the morning. Compared to placebo, caffeine intake increased CMJ height by 3.1% in the morning and 1.6% in the afternoon (P = .035), but it had no effect on BPT peak velocity (P = .381). Maximal strength and strength-endurance performances were not affected by the time-of-day or caffeine intake (all P > .3). No significant interaction (time-of-day x substance) was observed in any of the above-mentioned outcomes (all P > .1). In conclusion, an acute dose of caffeine in the morning was effective to restore CMJ performance to levels found in the afternoon, while this effect was not observed neither in BPTpeak velocity nor in lower- and upper-body maximal strength and strength-endurance performance. Moreover, lower- and upper-body ballistic performance were greater in the afternoon than in the morning in resistance-trained women, while the acute intake of caffeine was only effective to increase CMJ height.HighlightsBallistic performance is probably higher in the afternoon than in the morning in resistance-trained women.An acute intake of caffeine is effective to increase countermovement jump performance.The ingestion of an acute dose of caffeine in the morning restored countermovement jump performance to levels found in the afternoon.

Scheduling Concurrent Training 48 versus 72 h after Simulated Match Play: Effects on Neuromuscular Function and Fatigue

INTRODUCTION

Scheduling concurrent training (CT) during the in-season microcycle in field-based team sport is driven by prematch and postmatch recovery. This study examined the neuromuscular function, fatigue, and soreness responses to CT administered 48 h (match day (MD) + 2) versus 72 h (MD + 3) after match.

METHODS

Ten male recreational-level team sport athletes were monitored daily during two 5-d microcycles, which began with a simulated match (Soccer-specific Aerobic Field Test (SAFT90)) and CT performed either 48 or 72 h after match. Maximal voluntary force, quadriceps maximum EMG, voluntary activation, muscle contractile function (evoked twitch responses), muscle soreness, and fatigue were assessed immediately before and after the SAFT90, and every 24 up to 96 h after match. Outcome measures were also assessed immediately after CT. The CT consisted of an intermittent sprint protocol and a lower limb resistance training session separated by 1 h.

RESULTS

Immediately after the SAFT90 in both conditions, maximal voluntary force was below baseline (mean change (Δ), -14.6% ± 10.0%; P = 0.03), recovering 48 h post. Quadriceps contractile function (Δ, -31.5% ± 11.4%; P = 0.003) and voluntary activation (Δ, -8.9 ± 6.2%; P = 0.003) were also hampered after the SAFT90, recovering 24 h post in both conditions. In addition, the SAFT90 elicited elevated levels of fatigue and muscle soreness that recovered 24 h after the SAFT90 before increasing at 72 and 96 h post in the MD + 2 and MD + 3 conditions, respectively.

CONCLUSIONS

Recovery of fatigue was only observed at the end of the microcycle when CT was prescribed on MD + 2. Therefore, CT scheduled early (MD + 2) in the microcycle might avoid compromising forthcoming match preparation.

Acute Effects of Combined Lower-Body High-Intensity Interval Training and Upper-Body Strength Exercise on Explosive Strength Performance in Naturally Menstruating Women

PURPOSE

We aimed at investigating the acute effects of lower-body high-intensity interval training (HIIT) on upper- and lower-body explosive strength assessed by mean propulsive velocity (MPV) in naturally menstruating women. In addition, we assessed the combination of lower-body HIIT and squat, as well as lower-body HIIT and bench press, on bench press and squat MPV.

METHODS

Thirteen women (age: 23 [2] y, menstrual cycle length: 28.4 [2.0] d) completed 2 training modalities on separate days (separated by 30 [4.2] d) consisting of HIIT followed by lower-body (HIIT + LBS) or upper-body (HIIT + UBS) strength loading. Squat and bench press MPV were assessed before HIIT (T0), after HIIT (T1), after the strength loading (T2), and 24 hours postloading (T3).

RESULTS

Mixed factorial analysis of variance indicated a significant effect for time in bench press and squat (P < .001) but not for interaction. Pairwise comparison showed that bench press MPV remained unchanged (P = 1.000) at T1 but was reduced at T2 compared with T0 (HIIT + LBS: -8.2% [3.9%], HIIT + UBS: -13.8% [12.1%], P < .001) and T1 (HIIT + LBS: -7.1% [3.2%], HIIT + UBS: -12.7% [8.7%], P < .001). Squat MPV decreased at T1 (HIIT + LBS: -6.0% [8.8%], HIIT + UBS: -4.8% [5.4%], P = .009) and was found to be decreased at T2 compared with T0 in both conditions (HIIT + LBS: -6.9% [3.3%], HIIT + UBS: -7.4% [6.1%], P < .001) but not compared with T1 (P = 1.000). Bench press and squat MPV returned to baseline at T3 compared with T0 (P > .050).

CONCLUSION

Lower- but not upper-body explosive strength was reduced by HIIT. HIIT combined with upper- or lower-body strength loading resulted in a reduction of squat and bench press explosive strength.

Velocity-based resistance training: do women need greater velocity loss to maximize adaptations?

Purpose

Men and women typically display different neuromuscular characteristics, force–velocity relationships, and differing strength deficit (upper vs. lower body). Thus, it is not clear how previous recommendations for training with velocity-loss resistance training based on data in men will apply to women. This study examined the inter-sex differences in neuromuscular adaptations using 20% and 40% velocity-loss protocols in back squat and bench press exercises.

Methods

The present study employed an 8-week intervention (2 × week) comparing 20% vs. 40% velocity-loss resistance training in the back squat and bench press exercises in young men and women (~ 26 years). Maximum strength (1-RM) and submaximal-load mean propulsive velocity (MPV) for low- and high-velocity lifts in squat and bench press, countermovement jump and vastus lateralis cross-sectional area were measured at pre-, mid-, and post-training. Surface EMG of quadriceps measured muscle activity during performance tests.

Results

All groups increased 1-RM strength in squat and bench press exercises, as well as MPV using submaximal loads and countermovement jump height (P < 0.05). No statistically significant between-group differences were observed, but higher magnitudes following 40% velocity loss in 1-RM (g = 0.60) and in low- (g = 1.42) and high-velocity (g = 0.98) lifts occurred in women. Training-induced improvements were accompanied by increases in surface EMG amplitude and vastus lateralis cross-sectional area.

Conclusion

Similar increases in strength and power performance were observed in men and women over 8 weeks of velocity-based resistance training. However, some results suggest that strength and power gains favor using 40% rather than 20% velocity loss in women.

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.

Rate of Force Development as an Indicator of Neuromuscular Fatigue: A Scoping Review

Because rate of force development (RFD) is an emerging outcome measure for the assessment of neuromuscular function in unfatigued conditions, and it represents a valid alternative/complement to the classical evaluation of pure maximal strength, this scoping review aimed to map the available evidence regarding RFD as an indicator of neuromuscular fatigue. Thus, following a general overview of the main studies published on this topic, we arbitrarily compared the amount of neuromuscular fatigue between the "gold standard" measure (maximal voluntary force, MVF) and peak, early (≤100 ms) and late (>100 ms) RFD. Seventy full-text articles were included in the review. The most-common fatiguing exercises were resistance exercises (37% of the studies), endurance exercises/locomotor activities (23%), isokinetic contractions (17%), and simulated/real sport situations (13%). The most widely tested tasks were knee extension (60%) and plantar flexion (10%). The reason (i.e., rationale) for evaluating RFD was lacking in 36% of the studies. On average, the amount of fatigue for MVF (-19%) was comparable to late RFD (-19%) but lower compared to both peak RFD (-25%) and early RFD (-23%). Even if the rationale for evaluating RFD in the fatigued state was often lacking and the specificity between test task and fatiguing exercise characteristics was not always respected in the included studies, RFD seems to be a valid indicator of neuromuscular fatigue. Based on our arbitrary analyses, peak RFD and early phase RFD appear even to be more sensitive to quantify neuromuscular fatigue than MVF and late phase RFD.

CrossFit® Training Strategies from the Perspective of Concurrent Training: A Systematic Review

In the basic principles of CrossFit®, the goal is to improve fitness, related to the simultaneous development of strength and endurance. This is also the main idea of concurrent training, which has been researched since the 1980s. This article aimed to analyze the acute and chronic effects of CrossFit® and to assess the relevance of using the concurrent training methodology. The findings show that CrossFit® is an intense form of exercise that affects the function of the endocrine, immune, and central nervous systems. It also has potential in the development of strength and endurance parameters. These conclusions were compared with relevant concurrent training studies. Although the CrossFit® interventions (workouts of the day) have much in common with concurrent training, methodological recommendations can only be partially transferred. The approach for training and athlete development must be based on the originality of this sport.

Multivariate interpretation of the urinary steroid profile and training-induced modifications. The case study of a Marathon runner

The steroidal module of the athlete biological passport (ABP) introduced by the World Anti-Doping Agency (WADA) in 2014 includes six endogenous androgenic steroids and five of their concentration ratios, monitored in urine samples collected repeatedly from the same athlete, whose values are interpreted by a Bayesian model on the basis of intra-individual variability. The same steroid profile, plus dihydrotestosterone (DHT) and DHEA, was determined in 198 urine samples collected from an amateur marathon runner monitored over three months preceding an international competition. Two to three samples were collected each day and subsequently analyzed by a fully validated gas chromatography-mass spectrometry protocol. The objective of the study was to identify the potential effects of physical activity at different intensity levels on the physiological steroid profile of the athlete. The results were interpreted using principal component analysis and Hotelling's T² vs Q residuals plots, and were compared with a profile model based on the samples collected after rest. The urine samples collected after activity of moderate or high intensity, in terms of cardiac frequency and/or distance run, proved to modify the basal steroid profile, with particular enhancement of testosterone, epitestosterone, and 5α-androstane-3α,17β-diol. In contrast, all steroid concentration ratios were apparently not modified by intense exercise. The alteration of steroid profiles seemingly lasted for few hours, as most of the samples collected 6 or more hours after training showed profiles compatible with the "after rest" model. These observations issue a warning about the ABP results obtained immediately post-competition.

Cycling Exercise with Electrical Stimulation of Antagonist Muscles Increases Plasma Growth Hormone and IL-6

Performing aerobics and resistance exercise at exactly the same time has not been available although combining both types of exercise in one training program has been attempted. The hybrid training system (HTS) is a resistance exercise that combines voluntary concentric muscle contractions with electrically stimulated eccentric muscle contractions. We devised an exercise technique using HTS on a cycle ergometer (HCE). Growth hormone (GH) and lactate are indicators of adequate training intensity. Interleukin-6 (IL-6) reflects enhancing lipid metabolism. The purpose of this study was to show that HCE provides sufficient exercise to stimulate the secretion of GH, lactate and IL-6. We compared an HCE test with cycle ergometer alone (CE). Ten healthy male subjects performed HCE and CE tests for 30 minutes each. The workload of both tests was set the same at 40% of each subject's peak oxygen uptake. For HCE, 2-minute HTS and 1-minute rest intervals were repeated. GH, lactate, and IL-6 were evaluated before and immediately after exercise, and at 15, 30 and 60 minutes. GH and lactate increased immediately after HCE. Moreover, the degree of the increases in GH after HCE (0 and 15 minutes) was higher than that after CE. IL-6 increased after HCE at 30 min, and the rate of change was higher than for CE. These results showed that HCE was more efficient in stimulating acute increases in GH, lactate and IL-6 than CE at the same workload. We may be able to combine electrically stimulated resistance exercise with aerobic exercise using HCE.

Effects of <em>Hibiscus sabdariffa</em> Linn. on insulin-like growth factor binding protein 3 (IGFBP-3) to prevent overtraining syndrome

Background: Excessive physical exercises (overtraining) can increase the production of reactive oxygen species (ROS). One of the indicators of overtraining syndrome is a decrease in insulin-like growth factor binding protein 3 (IGFBP-3). Administration of Hibiscus sabdariffa Linn., a powerful antioxidant, is expected to boost endogenous antioxidants, and thus prevents overtraining. The aim of this study is to determine the effect of H. sabdariffa on IGFBP-3 levels in rats under ”overtraining physical excersice”.Methods: This experimental study was conducted on 30 male rats (Rattus norvegicus 200-250 grams), randomly allocated into 5 groups: 1) control group (C); 2) control with H. sabdariffa (C-Hib); 3) mild aerobic exercise (A-Ex); 4) overtraining exercise (OT); 5) overtraining exercise with H. Sabdariffa (OT-Hib). H. sabdariffa (400 mg/kg/d, 11 weeks) were administered orally via syringe cannula. IGFBP-3 was measured by using ELISA (Cusa bio kit) and data were analyzed with ANOVA test.Results: Plasma level of IGFBP-3 in the C and OT groups were 17.4 ± 10 mIU/L, the lowest in OT groups (10.7 ± 9.9 mIU/L) and the OT-Hib group had the highest level (31.5 ± 6.2 mIU/L). There was significant difference of the level IGFBP-3 in OT groups with A-Ex groups (10.7 ± 9.9 vs 23.5 ± 9.7 mIU/L; p < 0,05). The significant difference was also observed in the level of IGFBP 3 between C groups and the OT-Hib groups (17.4 ± 10 vs 31.5 ± 6.2; p < 0.05).Conclusion: Administration of H. sabdariffa can prevent the decrease of IGFBP-3 levels in overtraining rats, indicating its role in preventing overtraining syndrome.

Sex differences in human fatigability: mechanisms and insight to physiological responses

Sex-related differences in physiology and anatomy are responsible for profound differences in neuromuscular performance and fatigability between men and women. Women are usually less fatigable than men for similar intensity isometric fatiguing contractions. This sex difference in fatigability, however, is task specific because different neuromuscular sites will be stressed when the requirements of the task are altered, and the stress on these sites can differ for men and women. Task variables that can alter the sex difference in fatigability include the type, intensity and speed of contraction, the muscle group assessed and the environmental conditions. Physiological mechanisms that are responsible for sex-based differences in fatigability may include activation of the motor neurone pool from cortical and subcortical regions, synaptic inputs to the motor neurone pool via activation of metabolically sensitive small afferent fibres in the muscle, muscle perfusion and skeletal muscle metabolism and fibre type properties. Non-physiological factors such as the sex bias of studying more males than females in human and animal experiments can also mask a true understanding of the magnitude and mechanisms of sex-based differences in physiology and fatigability. Despite recent developments, there is a tremendous lack of understanding of sex differences in neuromuscular function and fatigability, the prevailing mechanisms and the functional consequences. This review emphasizes the need to understand sex-based differences in fatigability to shed light on the benefits and limitations that fatigability can exert for men and women during daily tasks, exercise performance, training and rehabilitation in both health and disease.

Physical activity - an important preanalytical variable

The concentration of several biochemical and hematological biomarkers is strongly influenced by a number of preanalytical variables. Several lines of evidence attest that short, middle, and long-term exercise, as well as the relative intensity of physical effort (from mild to strenuous), may influence a broad array of laboratory variables. The amount of extracellular release and clearance from blood of most of these biomarkers is markedly influenced by the biological characteristics of the molecule(s), level of training, type, intensity and duration of exercise, and time of recovery after training. It is hence noteworthy that test results that fall outside the conventional reference ranges in athletes not only may reflect the presence of a given disease, but may frequently mirror an adaptation to regular training or changes that have occurred during and/or following strenuous exercise, and which should be clearly acknowledged to prevent misinterpretation of laboratory data. The aim of this narrative review is to provide an update about the most significant changes of some biochemical and hematological biomarkers in response to physical exercise, for appropriate interpretation of these changes in the context of physically active subjects.