Acute effects of antagonist static stretching in the inter-set rest period on repetition performance and muscle activation

The Effects of Active Versus Passive Interset Rest Intervals in the Bench-Press Exercise in Resistance-Trained Men: A Randomized Crossover Study

PURPOSE

Interset rest (ISR) is a variable of resistance training (RT) that has received limited attention and focused mainly on the length of the ISR rather than examining the effects of different stimuli when using the same ISR duration. The aim of this study was to compare the effects of 2-minute passive (PAS) or active ISR (ACT) on intraset velocity loss, blood lactate concentrations, and rating of perceived exertion during bench press in resistance-trained men.

METHODS

Fourteen participants (23.64 [2.02] y, 82.79 [10.74] kg, 181.50 [7.02] m, maximal power in bench press 660 [113] W) completed 2 RT sessions of 5 × 8 repetitions at maximal velocity using individual optimal load for maximal power output with 2-minute PAS or ACT ISR. During the ACT, participants completed repetitions of vertical chest press at 5% to 10% 1-repetition maximum at a controlled velocity. The intraset velocity loss was measured using a lineal encoder, and blood lactate concentrations and rating of perceived exertion before and after each set were registered.

RESULTS

Intraset velocity loss was lower in ACT compared with the PAS protocol, without statistically significant differences (P = .571). Blood lactate concentrations increased across the session for both ISR protocols, but this increase was diminished in ACT compared with PAS, without statistical meaning (P > .05).

CONCLUSIONS

Continuing to perform the same activation during rest intervals was well-tolerated and may reduce the loss of performance due to accumulated workload throughout an RT session, suggesting that ACT may trigger a metabolic advantage in exercise performance for consecutive sets during an RT bout.

Superset Versus Traditional Resistance Training Prescriptions: A Systematic Review and Meta-analysis Exploring Acute and Chronic Effects on Mechanical, Metabolic, and Perceptual Variables

BACKGROUND

Supersets are a time-efficient resistance training (RT) method that involve the sequencing of two exercises with little or no rest between them. However, despite their common implementation during RT, a comprehensive and quantitative review is still lacking.

OBJECTIVES

The primary aim of this systematic review and meta-analysis was to compare the acute and chronic effects of superset and traditional set prescriptions on mechanical, metabolic, and perceptual variables. We also aimed to conduct subgroup analyses to determine the effect of different types of supersets (agonist-antagonist, similar biomechanical, and alternate peripheral supersets).

METHODS

A systematic literature search was conducted in PubMed, Web of Science, Embase, and EBSCO databases from inception to 10 February 2024. Studies written in English and meeting our inclusion criteria were included. Pooled meta-analysis and subgroup meta-analysis were performed using a random-effects model.

RESULTS

Nineteen studies involving 313 participants were included. Although there was considerable variance in certain outcomes, our estimated effects suggested that, compared with traditional set prescription, supersets allow for (1) a similar total number of repetitions [standardized mean differences (SMD) =  - 0.03; p = 0.92] and volume load (SMD = 0.05; p = 0.86) with a shorter session duration and increased training efficiency (SMD = 1.74; p = 0.01); (2) higher blood lactate concentration during (SMD = 0.94; p = 0.03) and after (SMD = 1.13; p < 0.01) RT; (3) higher energy cost during RT (SMD = 1.93; p = 0.04); (4) similar creatine kinase concentration after RT (SMD = 0.22; p = 0.36), surface electromyography (SMD = 0.01; p = 0.98), acute muscle swelling (SMD = - 0.28; p = 0.36) and blood pressure (systolic blood pressure [SMD = 0.08; p = 0.71], diastolic blood pressure [SMD = - 0.05; p = 0.85], and mean arterial pressure [SMD = - 0.03; p = 0.88]); (5) higher rating of perceived exertion (SMD = 0.77; p = 0.02) and similar perceived recovery (SMD = 0.32; p = 0.33); and (6) similar chronic adaptations in maximal strength (SMD = 0.10; p = 0.36), strength endurance (SMD = 0.07; p = 0.81), and muscle hypertrophy (SMD =  - 0.05; p = 0.87). The subgroup analysis revealed that utilizing agonist-antagonist supersets leads to a significant increase in the number of repetitions that are able to be completed compared with traditional sets (SMD = 0.68; p = 0.01). Similar biomechanical supersets led to less volume load (SMD =  - 1.08; p < 0.01) compared with traditional sets.

CONCLUSIONS

Supersets provide a time-efficient alternative to traditional RT, reducing session duration without compromising training volume, muscle activation, perceived recovery, or chronic adaptations in maximal strength, strength endurance, and muscle hypertrophy. Thus, supersets can be effectively implemented by athletes with busy schedules and RT enthusiasts whose main barrier to exercise is time. However, it should be noted that supersets generally induce higher internal loads, more severe muscle damage, and increased perceived exertion, potentially necessitating extended recovery times between sessions. Additionally, superset RT may have a similar potential to traditional RT in eliciting post-exercise hypotension. Regarding different types of supersets, agonist-antagonist supersets are more suitable for maintaining training volume, while similar biomechanical supersets concentrate stimulation on the same muscle group, compromising volume load.

PROTOCOL REGISTRATION

The original protocol for this review was prospectively registered with the International Prospective Register of Systematic Reviews (PROSPERO) in December 2023 (CRD42023491533).

The Acute Effects of Antagonist Static Stretching on Agonist Performance

Stretching the antagonist muscle to enhance agonist performance has gained considerable attention. However, most studies have focused on one stretching duration. Hence, the aim of this study was to compare varying durations (40-, 80-, and 120-seconds) of antagonist (dorsiflexors) static stretching (SS) on agonist (plantar flexors: PF) muscle performance. In this randomized crossover study, 16 participants (six females) underwent four sessions (40-, 80-, 120-s dorsiflexors SS and control), with pre- and post-intervention measurements of slow (600/s) and fast (2400/s) PF isokinetic, isometric peak torque, total work, stiff leg drop jump (SDJ) performance (height, reactive strength index (RSI) and peak power), and tibialis anterior and soleus electromyography (EMG). Dorsiflexors SS protocol involved 1x40-s (40-s), 2x40-s (80-s), and 3x40-s (120-s). There were no significant pre- to post-intervention changes in any parameter. A main effect for time demonstrated an overall decrease in fast (p < 0.0001, 5.9%, d = 0.24) and slow (p = 0.05, 6.6%, d = 0.24) isokinetic peak torque, total work (p = 0.02, 5.1%, d = 0.20) and all SDJ measures (SDJ height: p = 0.02, 2.7%, d = 0.15, RSI: p < 0.0001, 5.9%, d = 0.23, peak power: p = 0.002, 4.4%, d = 0.22). Soleus EMG decreased from pre- to post-SS after 120-s in both isometric (p = 0.002, 13.6%, d = 0.73) and slow isokinetic (p = 0.002, 12.3%, d = 0.91) peak torque as well as 80-s with slow isokinetic peak torque (p = 0.02, 6.6%, d = 0.75). In summary, different durations of dorsiflexors SS (40-s, 80-s, 120-s) did not significantly influence PF performance. However, deficits associated with a main effect for time suggested possible testing effects as detected with the control condition.

Multimodal Physical Therapy Management of Subcoracoid Impingement: A Case Report With One-Year Follow-Up and Ultrasound Measurement of Coracohumeral Distance

Subcoracoid impingement occurs due to mechanical encroachment of the subscapularis tendon in the subcoracoid space between the coracoid process and lesser tuberosity of the humerus. Although physical therapy is known to have a crucial role in managing this condition, to the best of our knowledge, there is no established physical therapy program in the literature. This case report aims to provide a detailed presentation and diagnosis of a subcoracoid impingement case and to investigate the effects of physical therapy on pain, disability, performance, muscle strength, and ultrasound measurements over a one-year follow-up period. The patient was a 24-year-old male working as a jeweler who had been suffering from dull anterior left shoulder pain for five years. The modified Hawkins-Kennedy test was positive. Additionally, palpation was pain-free, except for severe pain in the coracoid area. The patient was injected with xylocaine into the subcoracoid space and demonstrated a spontaneous relief of pain. Ultrasound imaging showed a narrower coracohumeral distance from full internal rotation on the affected side (0.85 cm) compared to the non-affected side (1.22 cm). Six weeks of multimodal physical therapy program was delivered to the patient. It consisted of electrophysical agents, manual therapy, and therapeutic exercise. Electrophysical agents included conventional transcutaneous electrical nerve stimulation, ice, and phonophoresis. Manual therapy included shoulder mobilization, myofascial release, thoracic mobilization, and posterior capsule stretches. Additionally, scapular muscle-strengthening and Rotator cuff strengthening exercises were delivered to the patient. The patient received 18 sessions for 6 weeks, at a rate of three times per week. Shoulder pain, function, and performance were measured by a numeric rating pain scale, shoulder pain and disability index, and timed push-up test, respectively. The shoulder muscle's peak isometric strength was measured by a hand-held dynamometer. Acromiohumeral distance, coracohumeral distance, supraspinatus thickness, and subscapularis thickness were measured by ultrasound imaging. Six weeks of multimodal physical therapy is a successful intervention for patients with subcoracoid impingement. It resulted in improvements in pain, function, performance, and muscle strength. An increase in coracohumeral distance from full internal rotation was observed at the end of the intervention, as well as after three months and one year.

Responses to a combined dynamic stretching and antagonist static stretching warm-up protocol on isokinetic leg extension performance

Antagonist static-stretching and dynamic-stretching are both effective at improving muscular performance. The purpose of this study was to investigate responses to a dynamic stretching warm-up protocol, a static-stretching warm-up protocol and a combined dynamic-stretching and antagonist static stretching warm-up protocol on isokinetic leg extension performance. Twelve participants completed a baseline (PRE) isokinetic knee-extension test at 60°.s-1 and 300°.s-1, following a 5 min warm-up on a cycle ergometer. Subsequently, participants completed the following warm-up protocols randomly over a three-week period: dynamic-stretching (DS); antagonist muscle static-stretching (AMSS) and dynamic followed by antagonist muscle static-stretching (DS-AMSS). A repeated measures analysis of variance (ANOVA) was conducted to determine where significant differences existed for peak torque, total work, average power, time-to-peak-torque and relative peak torque between warm-up protocols. DS-AMSS facilitated a significantly higher peak torque and total work compared to PRE, DS and AMSS at 60°.s-1 and 300°.s-1 P < 0.05, respectively). DS-AMSS caused significantly greater relative peak torque than PRE for 60°.s-1 and 300°.s-1 (P < 0.05). DS-AMSS resulted in significantly reduced time-to-peak-torque and increased average power at 60°.s-1 compared to PRE, DS and AMSS (P < 0.05). DS-AMSS and AMSS resulted in a significant reduction in time-to-peak-torque and increased average power compared to the PRE and DS (P < 0.05) at 300°.s-1.

Acute effects of different administration order of stretching exercises: effects on range of motion and cross-over effect

BACKGROUND

The aim of this manuscript is to investigate if stretching exercise administration order may influence outcomes pertinent to range of movement (ROM).

METHODS

A total sample of 108 participants was randomized into five groups. Eight sets of unilateral static stretching (SS) of 30s duration each with a 30s rest were administered to the right leg. One group underwent SS of the knee extensors (KE), another to the knee flexors (KF), another first to the KE and then to the KF, another first to the KF and then to the KE while the last group was used as control (CG). Each group was assessed for ROM of both lower limbs for either the KE and KF motion (passive hip extention [PHE] and passive straight leg raise [PSLR], respectively). Measures were assessed before (T0), immediately after (T1), and 15 minutes after the intervention (T2).

RESULTS

No differences were observed for time (T0 vs. T1 vs. T2) for all measures in the CG for both limbs. Time-x-group interactions were observed only in the intervention limb (P<0.0007 and 0.004, ES 0.73 and 0.55, for KE and KF, respectively). Within the intervention limb, a significant increase in the PHE was observed from T0 to T1 only in the KE and KF/KE groups. For measures of the PSLR, a significant increase was observed from T0 to T1 only in the KF and KE/KF groups. No differences neither for time or group were observed in the control limb.

CONCLUSIONS

Our results highlight that exercise administration order has an effect on ROM outcomes. Measures of ROM significantly increase only for the last stretched muscle in each intervention group. No crossover effect was observed in the contralateral limb.

Effects of Different Recovery Modalities on Delayed Onset Muscle Soreness, Recovery Perceptions, and Performance Following a Bout of High-Intensity Functional Training

The purpose of this study was to investigate the effects of the foam rolling technique and static stretching on perceptual and neuromuscular parameters following a bout of high-intensity functional training (HIFT), which consisted of 100 pull-ups, 100 push-ups, 100 sit-ups, and 100 air squats (Angie benchmark) in recreationally trained men (n = 39). Following baseline measurements (Feeling Scale, Visual Analogue Scale, Total Quality Recovery, Sit-and-Reach, Countermovement Jump, and Change-of-Direction t-test), the volunteers performed a single bout of HIFT. At the end of the session, participants were randomly assigned to one of three distinct groups: control (CONT), foam rolling (FR), or static stretching (SS). At the 24 h time-point, a second experimental session was conducted to obtain the post-test values. The level of significance was set at p < 0.05. Regarding power performance, none of the three groups reached pretest levels at 24 h point of the intervention. However, the CONT group still showed a greater magnitude of effect at the 24 h time-point (ES = 0.51, p ≥ 0.05). Flexibility presented the same recovery pattern as power performance (post × 24 h CONT = ES = 0.28, FR = ES = 0.21, SS = ES = 0.19). At 24 h, all groups presented an impaired performance in the COD t-test (CONT = ES = 0.24, FR = ES = 0.65, SS = ES = 0.56 p ≥ 0.05). The FR protocol resulted in superior recovery perceptions (pre × 24 h TQR = ES = 0.32 p ≥ 0.05). The results of the present study indicate that the use of FR and SS exercises may not be indicated when aiming to restore neuromuscular performance following a single bout of HIFT. The use of the FR technique during the cooldown phase of a HIFT session may be helpful in improving an individual's perception of recovery.

Does Stretching Training Influence Muscular Strength? A Systematic Review With Meta-Analysis and Meta-Regression

ABSTRACT

Thomas, E, Ficarra, S, Nunes, JP, Paoli, A, Bellafiore, M, Palma, A, and Bianco, A. Does stretching training influence muscular strength? A systematic review with meta-analysis and meta-regression. J Strength Cond Res 37(5): 1145-1156, 2023-The aim of this study was to review articles that performed stretching training and evaluated the effects on muscular strength. Literature search was performed using 3 databases. Studies were included if they compared the effects on strength following stretching training vs. a nontraining control group or stretching training combined with resistance training (RT) vs. an RT-only group, after at least 4 weeks of intervention. The meta-analyses were performed using a random-effect model with Hedges' g effect size (ES). A total of 35 studies ( n = 1,179 subjects) were included in this review. The interventions lasted for a mean period of 8 weeks (range, 4-24 weeks), 3-4 days per week, applying approximately 4 sets of stretching of approximately 1-minute duration. The meta-analysis for the stretching vs. nontraining control group showed a significant small effect on improving dynamic (k = 14; ES = 0.33; p = 0.007) but not isometric strength (k = 8; ES = 0.10; p = 0.377), following static stretching programs (k = 17; ES = 0.28; p = 0.006). When stretching was added to RT interventions, the main analysis indicated no significant effect (k = 17; ES = -0.15; p = 0.136); however, moderator analysis indicated that performing stretching before RT sessions has a small but negative effect (k = 7; ES = -0.43; p = 0.014); the meta-regression revealed a significant negative association with study length (β = -0.100; p = 0.004). Chronic static stretching programs increase dynamic muscular strength to a small magnitude. Performing stretching before RT and for a prolonged time (>8 weeks) can blunt the strength gains to a small-to-moderate magnitude. Performing stretching in sessions distant from RT sessions might be a strategy to not hinder strength development.

Acute Effects of a Percussive Massage Treatment on Movement Velocity during Resistance Training

The aim of this research was to verify whether the application of percussion therapy during inter-set rest periods increases the number of repetitions performed before reaching a 30% velocity loss threshold during a bench press exercise. Methods: Twenty-four male university students participated in this study (24.3 ± 1.3 years; 77.5 ± 8.3 kg; 177.0 ± 5.6 cm; 24.7 ± 2.6 kg∙m^-2). Participants were randomized into two groups: a percussion therapy group (PTG) and a control group (CG). They performed 4 sets at 70% of a one-repetition maximum before reaching a 30% velocity loss threshold with an inter-set recovery of 3 min. Results: The PTG performed a greater total number of repetitions compared to the CG (44.6 ± 4.8 vs. 39.5 ± 6.8; p = 0.047; ES = 0.867). No differences were observed for the different movement velocity variables and fatigue control (p > 0.05). Conclusions: Percussion therapy is an effective method to delay the loss of movement velocity in the bench press exercise.

No effect of passive stretching on neuromuscular function and maximum force-generating capacity in the antagonist muscle

Purpose

The present study investigated whether or not passive stretching increases the force-generating capacity of the antagonist muscle, and the possible neuromuscular mechanisms behind.

Methods

To this purpose, the neuromuscular function accompanying the force-generating capacity was assessed in 26 healthy male volunteers after passive stretching and in a control session. Before and after passive intermittent static stretching of the plantar flexors consisting of five sets × 45 s + 15 s-rest, maximum voluntary isometric contraction (MVC) and surface electromyographic root mean square (sEMG RMS) were measured in the tibialis anterior (the antagonist muscle). Additionally, evoked V wave, H-reflex, and M wave were elicited by nerve stimulation at rest and during MVC. Ankle range of motion (ROM) and plantar flexors MVC and EMG RMS were measured to check for the effectiveness of the stretching manoeuvre.

Results

No change in MVC [p = 0.670; effect size (ES) − 0.03] and sEMG RMS/M wave during MVC (p = 0.231; ES − 0.09) was observed in the antagonist muscle after passive stretching. Similarly, no change in V wave (p = 0.531; ES 0.16), H-reflex at rest and during MVC (p = 0.656 and 0.597; ES 0.11 and 0.23, respectively) and M wave at rest and during MVC (p = 0.355 and 0.554; ES 0.04 and 0.01, respectively) was observed. An increase in ankle ROM (p < 0.001; ES 0.55) and a decrease in plantar flexors MVC (p < 0.001; ES − 1.05) and EMG RMS (p < 0.05; ES − 1.72 to − 0.13 in all muscles) indicated the effectiveness of stretching protocol.

Conclusion

No change in the force-generating capacity and neuromuscular function of the antagonist muscle after passive stretching was observed.

Pre-stretching of the Hamstrings Before Squatting Acutely Increases Biceps Femoris Thickness Without Impairing Exercise Performance

Background: Bilateral squat exercise is widely used in resistance training (RT) programs to increase lower limb strength and muscle mass, but this exercise does not result in significant hypertrophy of the hamstrings. It has been speculated that stretching between sets with a certain degree of tension results in muscle hypertrophy, while acute stretching could decrease performance during maximal contractions.

Objective: This study investigated the acute effects of hamstring stretching before bilateral squatting on muscle thickness (MT), electromyography (EMG), and total training volume (TTV) on exercise performance.

Methods: Fourteen resistance-trained young men, with ∼7.5 years of RT experience, performed the 10 repetition maximum (RM) for the barbell squat in two sessions (test–retest) separated by period after 48 h. Participants engaged in two resistance exercise conditions separated by a 1 week recovery interval: one session employed hamstrings stretching and the other did not include hamstrings stretching. Before and after each resistance exercise session, the thickness of the quadriceps muscles and biceps femoris long head were obtained by ultrasound imaging. Moreover, the EMG amplitudes for the quadriceps muscles, biceps femoris, and iliocostalis muscles were recorded during back squat performance. The TTV was also evaluated for each exercise session.

Results: A significant increase in MT was observed after every set in both conditions for the evaluated quadriceps muscles (all p < 0.05), while for the biceps femoris, this effect was found only in the stretching condition (p < 0.05). EMG activity increased in the rectus femoris, vastus lateralis, and vastus medialis for the stretching condition. For the non-stretching condition, activity only increased in the vastus lateralis and medialis. There was no difference in EMG activity for the biceps femoris and iliocostalis in both conditions.

Conclusion: Stretching the hamstrings immediately before each set of the back squat can be used to acutely increase biceps femoris thickness without impairing squat performance.

Influence of power and maximal strength training on thermal reaction and vertical jump performance in Brazilian basketball players: a preliminary study

Study aim: To evaluate the effect of power and muscle strength training on skin temperature and the performance of the vertical jump with countermovement (CMJ).

Material and methods: The sample consisted of four male basketball athletes of the under-17 category (age: 15.75 ± 1.0 years). 48 hours after anthropometric evaluation and determination of the loads for 1 repetition maximum (1RM) in the leg extension exercise, the athletes were subjected, through crossover-type entrance, to power (PTP) and strength (STP) training protocols. The protocols consisted of three sets with loads of 60% and 90% of 1RM for PTP and STP, respectively. Thermographic images of the thighs were taken before and immediately after each training session.

Results: There were significant differences in results between the two training protocols, with increased total repetitions (t = 13.481; p < 0.05) and total training volume (t = 15.944; p < 0.05) in the PTP, and increase in the % of 1RM (t = 33.903; p < 0.05) and rating of perceived exertion (t = 6.755; p < 0.05) in the STP. The skin temperature before and after PTP and STP showed no significant differences. In the post-STP, the CMJ presented significant reductions in height (t = 3.318; p < 0.05), flight time (t = 3.620; p < 0.05), velocity (t = 3.502; p < 0.05), and force (t = 4.381; p < 0.05). There were no significant differences in pre-and post-STP CMJ.

Conclusions: Power and maximum strength training in the leg extension exercise performed until concentric failure appears to be a method that induces thermal stress on the skin. This training directly influenced the performance of the vertical jump after the stimulus.

Maximal strength performance, efficiency, and myoelectric responses with differing intra-set rest intervals during paired set training

INTRODUCTION

The purpose of this study was to investigate the effect of different rest intervals within paired sets (PS) on total work and training volume, efficiency (training volume load/session duration time), and myoelectric activity.

METHOD

Fifteen trained men participated in this study. Four experimental protocols were applied: P30 (30 s rest), P60 (60 s rest), P90 (90 s rest), and P120 (120 s rest). The PS bout consisted of a bench press (BP)/lat pull down (LPD), 30° incline bench press (BP30)/wide-grip seated row (SR), and triceps extension (TE)/biceps curl (BC) exercises. Surface electromyography (sEMG) activity of the biceps and triceps brachii were recorded.

RESULTS

Volume load (repetitions x number of exercise sets x loads) was significantly lower for the P30 (5385.8 ± 1224 kg) versus the P60 (6755.6 ± 1398.5 kg), P90 (7358.3 ± 1490.3 kg), and P120 (7463 ± 1310 kg) protocols. No significant differences in sEMG activity was noted between protocols. The efficiency (kg·min^-1) of P30 (633.6 ± 144) was significantly higher versus P60 (397.4 ± 82.2), P90 (288.5 ± 58.4), and P120 (219.5 ± 38.5).

CONCLUSION

Short intra-set rest intervals (60 s) within PS may be a potential alternative for increasing the volume load, since longer intra-rest (90 s and 120 s) intervals do not provide additional benefits.

Acute effect of intra-set static stretching on antagonists versus passive interval on the performance of maximum repetitions of agonists in leg extension machine

Abstract The aim of this study was to investigate the acute effect of intra-set antagonist static stretching (hamstrings) on the performance of maximum repetitions of knee extensors adopting muscle endurance training zone. The sample consisted of 15 healthy male volunteers with experience in strength training (23.7 ± 4.3 years, 81.9 ± 15.0 kg, 1.8 ± 0.1 m). Two experimental protocols were conducted: protocol without static stretching (PT) and antagonist stretching protocol (PAA) in the knee extension exercise. The results showed that there was no difference between protocols or interactions between protocols and sets in maximum repetitions performance (PT, set1 – 21.3 ± 3.4; set2 – 16.1 ± 1.9; set3 – 13.5 ± 1.3 / PAA, set1 – 21.0 ± 2.0; set2 – 16.7 ± 2.6; set3 – 13.7 ± 2.2) (p ≤ 0.05) (p ≤ 0.05). Therefore, antagonist static stretching does not influence performance of maximum repetitions of knee extensors over multiple sets focused on muscle endurance.

Effect of Interset Strategies on Acute Resistance Training Performance and Physiological Responses: A Systematic Review

Latella, C, Grgic, J, and Van der Westhuizen, D. Effect of interset strategies on acute resistance training performance and physiological responses: a systematic review. J Strength Cond Res XX(X): 000-000, 2019-The purpose of this systematic review was to evaluate the evidence surrounding the implementation of interset strategies to optimize acute resistance training performance. Searches of PubMed/MEDLINE, Scopus, and SPORTDiscus electronic databases were conducted. Studies that met the following criteria were included: (a) compared an interset strategy with a traditional passive rest interval in resistance training, (b) the assessed outcomes included performance or physiological responses, (c) resistance training was performed in a traditional dynamic fashion, (d) the study had an acute design, and (e) was published in English and in a peer-reviewed journal. A total of 26 studies were included in the review. When a given interset strategy was used, several studies reported improvements in the number of performed repetitions (i.e., greater total volume load), attenuation of the loss in velocity and power, reduced lactate levels, and in some cases, a decrease in perceived exertion. Dynamic agonist/static antagonist stretching, cooling, aerobic exercise, vibration, and individualized heart rate-based intervals seem to be the most effective strategies. However, the heterogeneity between study designs and methodologies suggests that careful consideration should be given to the type and specific application of the interset method being used. Given the acute nature of studies, extrapolation to any long-term benefits of using a given interset strategy remains limited. Collectively, coaches and sports scientists may consider using the most effective strategies based on practicality and equipment availability to optimize performance during the resistance training component of strength and conditioning programs.

Could inter-set stretching increase acute neuromuscular and metabolic responses during resistance exercise?

This study investigated the acute effects of inter-set static stretching (ISS) during resistance exercise (RE) on the subsequent neuromuscular and metabolic responses. Twelve resistance-trained men performed three different knee extension RE protocols comprised of seven sets of 10 repetitions in a counterbalanced fashion. The three protocols were: 1) ISS (subjects performed 25 sec of quadriceps stretching between sets during 40 sec rest interval); 2) control (CON, subject passively rested between sets for 40 sec); 3) traditional (TRA, subject passively rested between sets for 120 sec). Total work was lower (p < 0.05) in ISS than CON and TRA (p <0.05). The fatigue index was greater (p < 0.05) in ISS compared with CON and TRA. ISS also resulted in lower (p < 0.05) electromyography (EMG) amplitude during the 6th and 7th sets compared with TRA. Additionally, EMG frequency was lower (p < 0.05) from the 3rd to 5th sets during ISS compared to CON, and from the 3rd to 7th sets compared to TRA. Muscle swelling and blood lactate similarly increased (p > 0.05) in response to all protocols. These results indicate that ISS negatively impacts neuromuscular performance, and does not increase the metabolic stress compared to passive rest intervals.

Foam Rolling of Quadriceps Decreases Biceps Femoris Activation

Cavanaugh, MT, Aboodarda, SJ, Hodgson, DD, and Behm, DG. Foam rolling of quadriceps decreases biceps femoris activation. J Strength Cond Res 31(8): 2238-2245, 2017-Foam rolling has been shown to increase range of motion without subsequent performance impairments of the rolled muscle, however, there are no studies examining rolling effects on antagonist muscles. The objective of this study was to determine whether foam rolling the hamstrings and/or quadriceps would affect hamstrings and quadriceps activation in men and women. Recreationally, active men (n = 10, 25 ± 4.6 years, 180.1 ± 4.4 cm, 86.5 ± 15.7 kg) and women (n = 8, 21.75 ± 3.2 years, 166.4 ± 8.8 cm, 58.9 ± 7.9 kg) had surface electromyographic activity analyzed in the dominant vastus lateralis (VL), vastus medialis (VM), and biceps femoris (BF) muscles on a single leg landing from a hurdle jump under 4 conditions. Conditions included rolling of the hamstrings, quadriceps, both muscle groups, and a control session. Biceps femoris activation significantly decreased after quadriceps foam rolling (F(1,16) = 7.45, p = 0.015, -8.9%). There were no significant changes in quadriceps activation after hamstrings foam rolling. This might be attributed to the significantly greater levels of perceived pain with quadriceps rolling applications (F(1,18) = 39.067, p < 0.001, 98.2%). There were no sex-based changes in activation after foam rolling for VL (F(6,30) = 1.31, p = 0.283), VM (F(6,30) = 1.203, p = 0.332), or BF (F(6,36) = 1.703, p = 0.199). Antagonist muscle activation may be altered after agonist foam rolling, however, it can be suggested that any changes in activation are likely a result of reciprocal inhibition due to increased agonist pain perception.

Acute effects of different foam rolling volumes in the interset rest period on maximum repetition performance

Background:

Foam rolling (FR) is a ubiquitous intervention utilised for the purpose of acutely increasing the range of motion without subsequent decreases in performance. Thus, it is commonly used during the periworkout period—that is, prior to, during, or after an athlete's workout.

Objective:

This study investigated how different FR durations applied to the quadriceps during the interset rest periods affects the numbers of repetitions in the knee extension exercise.

Methods:

Twenty-five females completed four sets of knee extensions with 10 repetitions of maximum load to concentric failure on four occasions. Between each set, a 4-minute rest interval was implemented in which participants either passively rested or performed FR for different durations (60 seconds, 90 seconds, and 120 seconds). The 95% confidence intervals revealed a dose-dependent relationship in which longer durations of FR resulted in fewer completed repetitions.

Results:

On average, the number of repetitions with PR was 13.8% greater than that in FR120, 8.6% greater than that in FR90, and 9.1% greater than that in FR60.

Conclusion:

For the purposes of performance and likely adaptation, interset FR seems to be detrimental to a person's ability to continually produce force, and should not be applied to the agonist muscle group between sets of knee extensions.