Maximal Number of Repetitions at Percentages of the One Repetition Maximum: A Meta-Regression and Moderator Analysis of Sex, Age, Training Status, and Exercise

Concurrent training effects on H reflex, V wave and contractile properties of the plantar flexors: insights into different resistance training types

PURPOSE

This study explored neuromuscular adaptations following 11 weeks of concurrent training (CT) compared to resistance-only (R) and endurance-only (E) in trained men.

METHODS

Thirty participants were randomized into three groups (E, R, CT), training three times per week. Neuromuscular assessments involved plantar-flexion maximal voluntary isometric contraction (MVIC), rate of torque development (RTD), evoked potentials (H reflex and V wave) and contractile properties at baseline, mid-training (week 5), and post-training. Resistance training for R and CT groups involved two phases: weeks 1-5 (maximal strength development) and weeks 6-11 (explosive/reactive strength and muscle power development). Endurance training for the E and CT groups involved 30-min of running on the heavy-intensity domain.

RESULTS

MVIC increased similarly in the R and CT groups. The R group significantly improved peak and sequential RTD, soleus electromyographic (EMG) activity, V wave and contractile properties. Conversely, the CT group exhibited an interference effect during the first phase with no improvements in RTD or neuromuscular parameters. During the second phase, the CT group exhibited significant enhancements in sequential RTD, soleus EMG activity, H- and V-wave amplitude. The improvements in the E group were limited to H-reflex excitability.

CONCLUSION

These findings suggest that the magnitude of CT interference is modulated by the focus of resistance training (maximal vs explosive strength) being performed. However, it is relevant to note that contractile impairments seem to persist, likely due to endurance training in the heavy-intensity domain.

Optimizing Post-activation Performance Enhancement in Athletic Tasks: A Systematic Review with Meta-analysis for Prescription Variables and Research Methods

BACKGROUND

Post-activation performance enhancement (PAPE) has demonstrated efficacy in acutely improving athletic performance. However, its distinction from general warm-up (GW) effects remains ambiguous, and experimental designs adopted in most PAPE studies exhibit important limitations.

OBJECTIVES

The aims of this work are to (i) examine the effects of research methodology on PAPE outcomes, (ii) explore PAPE outcomes in relation to comparison methods, performance measures, GW comprehensiveness, recovery duration, participants' characteristics, conditioning activity (CA) parameters, and (iii) make recommendations for future PAPE experimental designs on the basis of the results of the meta-analysis.

METHODS

Four databases were searched for peer-reviewed English-language literature. Risk of bias was assessed using a modified Cochrane Collaboration's tool and PEDro scale. PAPE groups were compared with control groups, pre-conditioning activity (pre-CA) performances were compared with post-conditioning activity (post-CA) performances throughout a verification test in PAPE groups, and control groups were compared before and after the "rest" period using a three-level meta-analysis. Further analyses, including subgroup analysis and both linear and nonlinear meta-regression methods, were used to explore the effect of different moderating factors on PAPE magnitude. A subgroup analysis of GW comprehensiveness was conducted using four classification methods. One method classified GW as non-comprehensive (stretching or jogging only), partially comprehensive (stretching, jogging, and low-intensity self-weighted dynamic exercises), and comprehensive (adding maximal or near-maximal intensity CAs to a partially comprehensive GW). The other three classifications were adjusted according to the type and number of GW exercises. Certainty of evidence was assessed using the GRADE approach.

RESULTS

The final analysis included 62 PAPE studies (1039 participants, male: n = 857, female: n = 182) with a high risk of bias and low certainty of pooled evidence. A trivial PAPE effect was observed from pre- to post-CA (effect size [ES] = 0.12, 95% CI [0.06 to 0.19], prediction intervals [PI] = - 0.29 to 0.54); a small PAPE effect was observed when compared with a control group (ES = 0.30, 95% CI [0.20 to 0.40], PI [- 0.38 to 0.97]). The slightly greater effect against control resulted from a small decrease in performance in control groups (ES = - 0.08, 95% CI [- 0.13 to - 0.03], PI [- 0.30 to 0.14]), but there was no relationship with between PAPE recovery time (β = - 0.005, p = 0.149). Subgroup analyses showed that PAPE magnitude was greater for non-comprehensive GWs (ES = 0.16) than comprehensive (ES = 0.01) and partially comprehensive GWs (ES = 0.11). In contrast, the control group showed a decline in performance after comprehensive GW (ES = - 0.20). An inverted U-shaped PAPE was noted as a function of recovery time. In some cases, PAPE appeared to manifest at < 1 min post CA. Additionally, participants with longer training experience (ES = 0.36) and higher training levels (ES = 0.38) had larger PAPE magnitudes. PAPE effect was higher in females (ES = 0.51) than males (ES = 0.32) and mixed groups (ES = 0.16) but did not reach a significant difference (p > 0.05). Plyometric exercise (ES = 0.42) induced greater PAPE amplitude than traditional resistance exercise (ES = 0.23), maximal isometric voluntary contraction (ES = 0.31) and other CA types (ES = 0.24).

CONCLUSIONS

Although the overall pooled results for both PAPE pre- versus post-CA and PAPE versus control group comparisons showed significant improvement, the wider and past-zero prediction intervals indicate that future studies are still likely to produce negative results. The comprehensiveness of the GW, the time between GW and the pre-CA test, participant sex, training level, training experience, type of CA, number of CA sets, and recovery time after CA all influence the PAPE magnitude. The PAPE magnitude was trivial after comprehensive GW, but it was greater in studies with a control group (i.e., no CA) because performance decreased over the control period, inflating the PAPE effect. Finally, two theoretical models of PAPE experimental design and suggestions for methodological issues are subsequently presented. Future studies can build on this to further explore the effects of PAPE.

PROTOCOL REGISTRATION

The original protocol was prospectively registered (osf.io/v7sbt) with the Open Science Framework.

Gauging proximity to failure in the bench press: generalized velocity-based vs. %1RM-repetitions-to-failure approaches

BACKGROUND

This study compared the accuracy of three generalized approaches for estimating proximity to failure during the Smith machine bench press: (i) the relationship between relative load (%1RM) and maximum repetitions performed to failure (%1RM-RTF), (ii) the relationship between maximum repetitions to failure and fastest set velocity (RTF-velocity), and (iii) the relationship between repetitions left in reserve (RIR) and lifting velocity (RIR-velocity).

METHODS

Nineteen physically active men (22.9 ± 2.7 years old) with at least two years of resistance training experience participated. Their 1-repetition maximum (1RM = 86.8 ± 16.7 kg) was determined during the first session. In the second session, participants performed single sets to failure at 60% and 80% 1RM, with proximity to failure (2RIR and 4RIR) estimated using each approach.

RESULTS

The RIR-velocity relationship was the only approach that did not significantly deviate from the intended RIR (errors = -0.4 to 0.6 repetitions). In contrast, both the %1RM-RTF and RTF-velocity relationships overestimated the intended RIR at 60%1RM for both 2RIR (2.9 and 5.8 repetitions, respectively) and 4RIR (2.8 and 5.7 repetitions, respectively), while no significant differences were observed at 80%1RM (errors = -0.6 to 0.9 repetitions). The RIR-velocity relationship generally demonstrated the lowest absolute errors compared to the actual RIR (1.3 ± 0.7 repetitions), with greater differences compared to the other two approaches at lighter loads and closer proximities to failure.

CONCLUSIONS

In the absence of individual relationships, the general RIR-velocity relationship should be used by coaches to control the proximity to failure of their athletes during the bench press exercise.

Relationship between 10 repetition maximum for chest press, leg press, and muscle mass measured using bioelectrical impedance analysis in healthy young adults

[Purpose] This study aimed to examine the relationship between bioelectrical impedance analysis measurements and 10 repetition maximum for chest press and leg press, and to develop a regression model to determine if bioelectrical impedance analysis can predict 10 repetition maximum in healthy young adults. [Participants and Methods] Ninety-four healthy adults participated in the study. Correlations between 10 repetition maximum and bioelectrical impedance analysis measurements were calculated, and simple linear regression was performed using bioelectrical impedance analysis measurements as independent variables to develop 10 repetition maximum prediction models. [Results] Significant correlations were found between 10 repetition maximum and bioelectrical impedance analysis measurements. The regression models for 10 repetition maximum for chest press based on upper limb muscle mass, skeletal muscle mass, and skeletal muscle mass index were Y=16.40X-13.27, Y=3.81X-36.78, and Y=20.51X-81.27, respectively. The regression models for 10 repetition maximum for leg press based on lower limb muscle mass, skeletal muscle mass, and skeletal muscle mass index were Y=12.60X-3.21, Y=8.09X-24.39, and Y=43.68X-119.60, respectively. [Conclusion] These findings may contribute to developing a safe and efficient method for measuring 10 repetition maximum, which can be useful in resistance training prescriptions.

Tissue oxygenation in response to low-load and high-load back squats with continuous blood flow restriction in athletes

To determine muscle oxygenation with continuous blood flow restriction (BFR) training in high load (HL), 80% one-repetition maximum (1RM) and low load (LL), 30% 1RM squat exercises. In week-2 of a 4-week resistance training programme as part of their 3-set training routine, two groups of athletes (n = 4 each), one performing HL training with low cuff pressure (20% arterial occlusion pressure (AOP)), the other LL training with high cuff pressure (60% AOP) had muscle oxygenation assessed with near-infrared spectrophotometry (NIRS), arterial oxygen saturation (SPO2), heart rate (HR), barbell velocity and ratings of perceived exertion (RPE) during barbell back squats (BBS). Changes in the vastus lateralis oximetry were compared to pre- and post-training squat (1RM). Across athletes, there were significant associations between two pre-set-3 exercise variables and post-training 1RM, Tissue Saturation Index (TSI) (R2 = 0.92, p < 0.0002) and HHb concentration (R2 = 0.79, p < 0.003). Generalised regression models indicated that TSI % and HHb concentrations before and after set 3 timepoints were significant predictors of post-training 1RM in the LL group (R2 = 0.99, BIC = -24.9). Well-tolerated continuous LL-BFR training provided greater increases in strength than HL-BFR in athletes.

Conceptualizing a load and volume autoregulation integrated velocity model to minimize neuromuscular fatigue and maximize neuromuscular adaptations in resistance training

Resistance training (RT) load and volume are considered crucial variables to appropriately prescribe and manage for eliciting the targeted acute responses (i.e., minimizing neuromuscular fatigue) and chronic adaptations (i.e., maximizing neuromuscular adaptations). In traditional RT contexts, load and volume are generally pre-prescribed; thereby, potentially yielding sub-optimal outcomes. A RT concept that individualizes programming is autoregulation: a systematic two-step feedback process involving, (1) monitoring performance and its constituents (fitness, fatigue, and readiness) across multiple time frames (short-, moderate-, and long-term); and (2) adjusting programming (i.e., load and volume) to elicit the targeted goals (i.e., responses and adaptations). A growing body of load and volume autoregulation research has accelerated recently, with several meta-analyses suggesting that autoregulation may provide a small advantage over traditional RT. Nonetheless, the existing literature has typically conceptualized these current autoregulation methods as standalone practices, which has limited their extensive utility in research and applied settings. The primary purpose of this review was three-fold. Initially, we synthesized the current methods of load and volume autoregulation, while disseminating each method's main advantages and limitations. Second, we conceptualized a theoretical Integrated Velocity Model (IVM) that integrates the current methods for a more holistic perspective of autoregulation that may potentially augment its benefits. Lastly, we illustrated how the IVM may be compared to the current methods for future directions and how it may be implemented for practical applications. We hope that this review assists to contextualize a novel autoregulation framework to help inform future investigations for researchers and practices for RT professionals.

Low-Load Blood-flow Restriction Training for Medial Tibial Stress-Syndrome in Athletes: A Case Series

Background

Medial tibial stress syndrome (MTSS) is a common overuse injury characterized by activity-induced pain along the distal medial tibial border. Current best practice includes rest and progressive resistance training. However, some patients with MTSS may be unable to tolerate the loading during exercise. Blood-flow restriction training using low loads (LL-BFR) may induce similar physiological and structural adaptations as heavy resistance training but without peak loads. This could potentially allow the athlete to continue sports activities during rehabilitation.

Purpose

The purpose of this case series was to describe an exercise program utilizing LL-BFR training for athletes with running-related MTSS.

Study design

Case series.

Methods

Six recreational athletes (one handball player, one soccer player, and four runners) with MTSS were recruited. Inclusion criteria included pain along the distal two-thirds medial tibial border occurring during or after activity. Exclusion criteria were symptoms of compartment syndrome, tibial stress fracture, or contraindications for BFR training. Participants underwent a progressive six-week home-based LL-BFR training intervention with three sessions per week and were allowed to continue sports activities if pain was ≤ NRS 5. Outcome measures included change in standardized running performance (distance and pain level), pain pressure threshold (algometry), and self-reported physical function.

Results

Five athletes experienced improvements in running performance (pain and/or distance) and self-reported function. One athlete sustained an injury unrelated to the LL-BFR training, and therefore the running post-test could not be completed. Adherence to exercise was high, and post-test interviews revealed positive feedback on the training method, with no side effects reported.

Conclusion

This case series demonstrated that following a therapeutic exercise program utilizing LL-BFR training improvements in pain and function were seen in athletes with MTSS. BFR may allow clinicians to prescribe lower-load exercises, facilitating continued sports participation. Future research should compare the effectiveness of exercise programs for MTSS with and without LL-BFR training.

Level of Evidence

Level V.

The Impact of Stance Width on Kinematics and Kinetics During Maximum Back Squats

ABSTRACT

Larsen, S, Zee, Md, and Tillaar, Rvd. The impact of stance width on kinematics and kinetics during maximum back squats. J Strength Cond Res 39(1): 1-9, 2025-This study compared the lower extremity peak net joint moments (NJMs) and muscle forces between wide and narrow stance widths defined as 1.7 and 0.7 acromion width in the last repetition of the concentric phase in 3 repetition maximum back squats. Twelve recreationally trained men (age:25.3 ± 2.9 years, height:179 ± 7.7 cm, body mass:82.8 ± 6.9 kg) volunteered for the study. The NJMs were estimated using inverse dynamics and individual muscle forces with static optimization. The main findings of interest were that the wide stance resulted in statistically smaller knee flexion angles (Cohen's d: 0.9; 95% confidence interval [CI]: -17.96 to -3.18°), knee extension NJMs [d: 1.45; 95% CI: -1.56 to -0.61 Nm·kg-1], and vastii forces [d: 1.3; 95% CI: -27.7 to -0.9.5 N·kg-1] compared with the narrow stance. Moreover, we observed significantly larger hip abduction angles [d: 3.8; 95% CI: 12.04 to 16.86°] for the wide stance. Hence, we suggest that recreationally trained men aiming to optimize muscle forces in the vastii muscles during maximum back squat training should consider adopting a narrow stance.

Rate of Perceived Exertion Based on Repetitions in Reserve Versus Percentage of One-Repetition Maximum for Resistance Training Prescription in Cardiac Rehabilitation: A Pilot Study

The aims of this study were to assess the efficacy of the rate of perceived exertion (RPE) scale based on the number of repetitions in reserve (RIR) before exhaustion for the prescription of resistance training in cardiac rehabilitation and to compare it to the percentage of estimated one-repetition maximum (1RM) prescription method. Sixteen male patients (age 60 ± 8) with history of coronary artery disease were randomly assigned to two resistance training rehabilitation protocols lasting nine weeks and consisting of three sessions per week, with the same exercise selection, number of sets and repetitions, and rest periods, but different load prescription method (RPE vs. %1RM). Patients' strength was evaluated pre- and post-intervention. Patients in the RPE group showed significant increases in strength across all the exercises of the protocol (leg press 24.25 ± 17.07 kg; chest press 7.25 ± 3.41 kg; seated row 13.88 ± 7.57 kg; leg extension 14.24 ± 4.53 kg; shoulder press 5.75 ± 4.06 kg; lat pulldown 7.50 ± 4.66 kg). Post-intervention between-group analysis showed no differences in strength gains (leg press p = 0.955; chest press p = 0.965; seated row p = 0.763; leg extension p = 0.565; shoulder press p = 0.868; lat pulldown p = 0.780) and trivial effect sizes (ES) for one prescription method over the other (leg press ES = -0.03; chest press ES = 0.00; seated row ES = 0.10; leg extension ES = -0.29; shoulder press ES = 0.18; lat pulldown ES = 0.05). RPE based on RIR seems to be an effective prescription method for resistance training in cardiac rehabilitation, showing similar efficacy to the standardized practice of percentage of 1RM.

Enhanced Muscle Endurance Through Self-regulated Dual-Task Exercises in Elbow Fracture Rehabilitation: A Cross-sectional Study

OBJECTIVE

The main objective of this study was to investigate the effect of a self-regulated dual task on muscle endurance within a single rehabilitation session in patients recovering from an elbow fracture.

DESIGN

This is a cross-sectional study of individuals recovering from elbow fractures ( N = 20). Muscle endurance was tested using elastic bands at Borg's CR10 intensity 3-during four conditions: single-task and dual-task for elbow flexion and extension.

RESULTS

The cognitive condition significantly influenced muscle endurance ( P < 0.001), while the type of elbow exercise (flexion or extension) did not show significant differences ( P = 0.592). The perceived difficulty of the tasks showed a significant interaction effect ( P = 0.032). The dual-task condition showed an average increase of about 15 repetitions. A moderate negative correlation was found between the differences in repetitions and the perceived difficulty of the flexion exercise ( r = 0.677, P = 0.001).

CONCLUSIONS

Dual-task with self-regulation enhances muscle endurance among patients recovering from an elbow fracture. However, the improvements seem to depend on the perceived difficulty of the cognitive task. Future randomized controlled trials are required to understand the therapeutic implications of dual-tasking.

Exploring the Dose-Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions

BACKGROUND

The proximity to failure in which sets are terminated has gained attention in the scientific literature as a potentially key resistance training variable. Multiple meta-analyses have directly (i.e., failure versus not to failure) or indirectly (e.g., velocity loss, alternative set structures) evaluated the effect of proximity to failure on strength and muscle hypertrophy outcomes categorically; however, the dose-response effects of proximity to failure have not been analyzed collectively in a continuous manner.

OBJECTIVE

To meta-analyze the aforementioned areas of relevant research, proximity to failure was quantified as the number of repetitions in reserve (RIR). Importantly, the RIR associated with each effect in the analysis was estimated on the basis of the available descriptions of the training interventions in each study. Data were extracted and a series of exploratory multilevel meta-regressions were performed for outcomes related to both strength and muscle hypertrophy. A range of sensitivity analyses were also performed. All models were adjusted for the effects of load, method of volume equating, duration of intervention, and training status.

RESULTS

The best fit models for both strength and muscle hypertrophy outcomes demonstrated modest quality of overall fit. In all of the best-fit models for strength, the confidence intervals of the marginal slopes for estimated RIR contained a null point estimate, indicating a negligible relationship with strength gains. However, in all of the best-fit models for muscle hypertrophy, the marginal slopes for estimated RIR were negative and their confidence intervals did not contain a null point estimate, indicating that changes in muscle size increased as sets were terminated closer to failure.

CONCLUSIONS

The dose-response relationship between proximity to failure and strength gain appears to differ from the relationship with muscle hypertrophy, with only the latter being meaningfully influenced by RIR. Strength gains were similar across a wide range of RIR, while muscle hypertrophy improves as sets are terminated closer to failure. Considering the RIR estimation procedures used, however, the exact relationship between RIR and muscle hypertrophy and strength remains unclear. Researchers and practitioners should be aware that optimal proximity to failure may differ between strength and muscle hypertrophy outcomes, but caution is warranted when interpreting the present analysis due to its exploratory nature. Future studies deliberately designed to explore the continuous nature of the dose-response effects of proximity to failure in large samples should be considered.

Increased Neuromuscular Activity, Force Output, and Resistance Exercise Volume When Using 5-Minute Compared with 2-Minute Rest Intervals Between the Sets

ABSTRACT

McMahon, G, Best, N, Coulter, T, and Erskine, RM. Increased neuromuscular activation, force output and resistance exercise volume when using 5-minute compared with 2-minute rest intervals between the sets. J Strength Cond Res 38(9): 1527-1534, 2024-Longer rest intervals between resistance exercise (RE) sets may promote greater muscle hypertrophy and strength gains over time by facilitating the completion of greater training volume and intensity. However, little is known about the acute neuromuscular responses to RE sets incorporating longer vs. shorter rest intervals. Using a within-subject, crossover design, 8 healthy, young subjects completed 2 separate acute bouts of 4 sets of 8 × 3-s maximal isometric contractions using either a 2-minute (REST-2) or 5-minute (REST-5) rest interval between sets. Peak torque (PT) and electromyography (EMG) were measured pre and 5 minutes postexercise. Peak torque and mean torque (MT), EMG, mean, and median frequencies were measured during each set, whereas blood lactate (BLa), heart rate (HR), and rating of perceived exertion (RPE) were measured following each set. Peak torque and MT were lower ( p < 0.05) in sets 3 and 4, and sets 2-4 in REST-2 compared with REST-5, respectively. Electromyography and BL were lower and higher, respectively, in REST-2 vs. REST-5. There was no main effect of condition on HR or RPE. Pre-to-post exercise reductions in PT (-17 ± 9% vs. -4 ± 7%) and EMG (-29 ± 14% vs. -10 ± 7%) were greater ( p < 0.001) in REST-2 vs. REST-5. Total exercise volume was less in REST-2 vs. REST-5 (9,748 ± 2296 N·m -1 vs. 11,212 ± 2513 N·m -1 , p < 0.001). These results suggest that incorporating 5-minute between-set rest intervals into a resistance exercise session facilitates improved neuromuscular function, increased exercise volume, and less metabolic stress compared with 2-minute rest intervals. Thus, 5-minute rest intervals may be more efficacious for promoting muscle hypertrophy and strength gains in a chronic resistance training program.

Effects of 34 Weeks of Military Service on Body Composition and Physical Fitness in Military Cadets of Angola

Military personnel need physical fitness to effectively carry out operational military activities within their specific field of operation. This research investigates the effects of a 34-week training program on Angolan cadets' body composition, muscle strength, and cardiorespiratory fitness. Seventy-four volunteer recruits, aged 18 to 26 years, were monitored during their eight-month military service, following an exercise program protocol comprising 12 weeks of strength training followed by 24 weeks of endurance training. Anthropometric variables, including body mass, body mass index, and fat mass, were assessed, along with cardiorespiratory fitness (VO2max), sprint performance, countermovement jump (CMJ), medicine ball throw, push-ups, and curl-ups. The physical training protocol encompassed running sessions, strength exercises, agility drills, and flexibility exercises. The initial assessment revealed gender differences in various parameters such as body mass, body fat percentage, VO2max, sprinting, countermovement jump (CMJ), medicine ball throw, and push-ups. Following the training program, changes were observed in all variables (effect size between 0.48 and 2.33, p < 0.01) for the participants. Significant interactions (sex × time) were found in body mass (F = 5.18, p = 0.03, ηp2 = 0.06), body fat percentage (F = 5.31, p < 0.01, ηp2 = 0.14), and medicine ball throw (F = 10.84, p < 0.01, ηp2 = 0.13). Specifically, males exhibited a greater reduction in body mass (females: 2.70%, males: 3.47%, p < 0.05) and a substantial improvement in ball throwing performance (females: 7.74%, males: 11.47%, p < 0.01), while females experienced a greater reduction in fat mass (females: 5.34%, males: 3.15%, p < 0.01). The physical training regimen effectively influenced body composition, particularly in enhancing strength performance among males. The integration of exercise programs with military service led to a notable reduction in fat tissue and an increase in lean tissue. Hence, the development of tailored training protocols is imperative to enhance the physical capacity and overall health of military recruits, considering sex-specific characteristics and physical attributes.

Muscle Strength Preservation During Repeated Sets of Fatiguing Resistance Exercise: A Secondary Analysis

ABSTRACT

Nuzzo, JL. Muscle strength preservation during repeated sets of fatiguing resistance exercise: A secondary analysis. J Strength Cond Res 38(6): 1149-1156, 2024-During sustained or repeated maximal voluntary efforts, muscle fatigue (acute strength loss) is not linear. After a large initial decrease, muscle strength plateaus at approximately 40% of baseline. This plateau, which likely reflects muscle strength preservation, has been observed in sustained maximal isometric and repeated maximal isokinetic contractions. Whether this pattern of fatigue occurs with traditional resistance exercise repetitions with free weights and weight stack machines has not been overviewed. Here, the aim was to determine whether the number of repetitions completed across 4 or more consecutive repetitions-to-failure tests exhibits the same nonlinear pattern of muscle fatigue. A secondary analysis was applied to data extracted as part of a recent meta-analysis on repetitions-to-failure tests. Studies were eligible if they reported mean number of repetitions completed in 4-6 consecutive repetitions-to-failure tests at a given relative load. Twenty-nine studies were included. Overall, the results show that the number of repetitions completed in consecutive repetitions-to-failure tests at a given load generally decreases curvilinearly. The numbers of repetitions completed in sets 2, 3, 4, 5, and 6 were equal to approximately 70, 55, 50, 45, and 45% of the number of repetitions completed in set 1, respectively. Longer interset rest intervals typically attenuated repetition loss, but the curvilinear pattern remained. From the results, a chart was created to predict the number of repetitions across 6 sets of resistance exercise taken to failure based on the number of repetitions completed in set 1. The chart is a general guide and educational tool. It should be used cautiously. More data from a variety of exercises, relative loads, and interset rest intervals are needed for more precise estimates of number of repetitions completed during repeated sets of fatiguing resistance exercise.

Resistance Exercise Minimal Dose Strategies for Increasing Muscle Strength in the General Population: an Overview

Many individuals do not participate in resistance exercise, with perceived lack of time being a key barrier. Minimal dose strategies, which generally reduce weekly exercise volumes to less than recommended guidelines, might improve muscle strength with minimal time investment. However, minimal dose strategies and their effects on muscle strength are still unclear. Here our aims are to define and characterize minimal dose resistance exercise strategies and summarize their effects on muscle strength in individuals who are not currently engaged in resistance exercise. The minimal dose strategies overviewed were: "Weekend Warrior," single-set resistance exercise, resistance exercise "snacking," practicing the strength test, and eccentric minimal doses. "Weekend Warrior," which minimizes training frequency, is resistance exercise performed in one weekly session. Single-set resistance exercise, which minimizes set number and session duration, is one set of multiple exercises performed multiple times per week. "Snacks," which minimize exercise number and session duration, are brief bouts (few minutes) of resistance exercise performed once or more daily. Practicing the strength test, which minimizes repetition number and session duration, is one maximal repetition performed in one or more sets, multiple days per week. Eccentric minimal doses, which eliminate or minimize concentric phase muscle actions, are low weekly volumes of submaximal or maximal eccentric-only repetitions. All approaches increase muscle strength, and some approaches improve other outcomes of health and fitness. "Weekend Warrior" and single-set resistance exercise are the approaches most strongly supported by current research, while snacking and eccentric minimal doses are emerging concepts with promising results. Public health programs can promote small volumes of resistance exercise as being better for muscle strength than no resistance exercise at all.

Concurrent Resistance and Cardiorespiratory Training in Patients with Hypertrophic Cardiomyopathy: A Pilot Study

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.

Relationship between maximal oxygen uptake, within-set fatigue and between-set recovery during resistance exercise in resistance-trained men and women

BACKGROUND

The primary aim of this study was to examine the relationship between maximal oxygen update (V̇O2max) and within-set fatigue and between-set recovery during resistance exercise in men and women.

METHODS

We examined the relationship between V̇O2max and various indices of fatigue and recovery during parallel squats (3 sets, 90 s rest, 70% of 1RM to failure) and isokinetic knee extensions (3 × 10 maximal repetitions at 60 deg/s, 45 s rest) in 28 (age 27.0 ± 3.6 years) resistance-trained subjects (14 men and 14 women). We also examined whether there were sex differences in within-set fatigue and between-set recovery.

RESULTS

V̇O2max was weakly related to recovery and fatigue in both men and women (range of P-values for V̇O2max as a covariate; 0.312-0.998, range of R-values, 0.005-0.604). There were no differences between the sexes in fatigue within a set for the squat, but men showed less within-set fatigue than women in the first set of the isokinetic knee extension exercise (~ 8% torque loss difference, main effect of sex P = 0.034). Regarding recovery between sets, men showed greater relative peak power (P = 0.016) and peak torque (P = 0.034) loss between sets in both exercises, respectively, compared to women. Women also tended to complete more repetitions than men (main effect of sex, P = 0.057). Loss of peak torque between sets in knee extension was evident in both absolute and relative (%) values in men but not in women.

CONCLUSIONS

Our study suggests that aerobic capacity is weakly associated with within-set fatigue and between-set recovery in resistance training in both men and women. Women and men show comparable levels of within-set fatigue in the multi-joint squat, but women show more within-set fatigue during the single-joint isokinetic knee extension compared with men. In contrast, women recover better than men between sets in both exercises.

Comparison of kinematics and electromyography in the last repetition during different maximum repetition sets in the barbell back squat

Background

The barbell squat is an exercise used to strengthen the lower limbs, with implications for both performance in sports and improving movement during everyday tasks. Although the exercise is being trained across a variety of repetition ranges, the technical requirements may vary, affecting appropriate repetition range for specific training goals.

Methods

A randomised within-subject design was used to compare kinematics and surface electromyography (EMG) in the lower extremities during different concentric phases (pre-, sticking- and post-sticking region) of the last repetition when performing squats at different repetition maximums (RMs). Thirteen strength-trained men (age: 23.6 ± 1.9 years; height: 181.1 ± 6.5 cm; body mass: 82.2 kg, 1RM: 122.8 ± 16.2, relative strength: 1.5 ± 0.2 x body mass in external load) performed a 1, 3, 6, and 10RM squat, in a randomised order.

Results

The main findings were that barbell-, ankle-, knee- and hip kinematics were similar across different repetition ranges, except for a smaller trunk lean at 1RM in the pre-sticking region compared to other repetitions and in the sticking region compared to 10RM (p ≤ 0.04). Furthermore, 1RM revealed significantly higher EMG amplitude in the vastus lateralis, gastrocnemius and soleus in the sticking and post-sticking regions when compared to 10RM. It was concluded that 10RM may locally fatigue the vastus lateralis and plantar flexors, explaining the lower EMG amplitude. The observed differences indicate that requirements vary for completing the final repetition of the 10RM compared to the 1RM, an important aspect to consider in training to enhance 1RM strength.