Traditional Resistance Exercise Research Articles

Flywheel resistance training promotes unique muscle architectural and performance-related adaptations in young adults.

The purpose of this study was to examine the skeletal muscle hypertrophic, architectural, and performance-related adaptations in response to volume-matched, total-body flywheel versus traditional resistance training in a randomized, non-exercise controlled study in physically active young adults. Thirty-one healthy young adults (24±3y) were randomized to 10weeks of traditional resistance training (TRT; n=7F/5M), flywheel training (FWRT; n=7F/4M), or a habitual activity control (CON; n=5F/3M). Maximal voluntary isometric torque (MVIT), one repetition-maximum (1RM) for the free weight squat and bench press, three repetition work maximum (3Wmax) for the flywheel squat and bench press, countermovement jump height, and broad jump distance, as well as site-specific muscle hypertrophy, fascicle length (FL), and pennation angle, were measured. Both TRT and FWRT increased MVIT (p≤0.021) and FFM (p≤0.032) compared to CON. However, TRT promoted superior improvements in free weight squat and bench 1RM (p<0.001), and FWRT improved flywheel 3Wmax squat and bench (p<0.001). FWRT increased the FL and cross-sectional area of the distal VL, countermovement jump height, and broad jump distance (p≤0.048), whereas TRT increased the pennation angle and cross-sectional area of the proximal VL. Therefore, 10weeks of volume-matched, total-body traditional, and flywheel resistance training similarly increased maximal isometric strength and fat-free mass. However, FWRT promoted unique skeletal muscle architectural adaptations that likely contributed to region-specific VL hypertrophy and jump performance improvements. Thus, FWRT provides a novel training stimulus that promotes architectural adaptations that support improved athletic performance in a manner that is not provided by traditional resistance exercise training.

Cardiorespiratory and aerobic demands of squat exercise

Squatting, a traditional resistance exercise classified as strength training, relies on anaerobic pathways, but its aerobic aspects remain unclear. We examined heart rate and oxygen demand during squats, exploring variations across different strength statuses. It fills gaps in understanding the cardiorespiratory effects of squatting, especially during multiple sets. Twenty-two young healthy resistance trained men (age: 28 ± 4 years) participated. Maximal oxygen consumption (V̇O2max) and 1 repetition maximum (RM) of squat were measured. Participants performed 5 sets of squat exercises at 65% of 1RM for 10 repetitions with 3-min rest intervals. Heart rate and pulmonary gas exchange were measured during the squat exercise. Participants were divided into high strength (HS; upper 50%) and low strength (LS; lower 50%) groups based on a median split of their 1 RM squat values (normalized to their body weight). During 5 sets of squat exercise, oxygen consumption (V̇O2) increased up to 47.8 ± 8.9 ml/kg/min, corresponding to 100.6% of predetermined V̇O2max. The HS group achieved a greater highest point of V̇O2 in relation to V̇O2max than the LS group (108.0 vs. 93.7%). During the exercise intervals, V̇O2 exceeded V̇CO2, while during the rest intervals, V̇CO2 surpassed V̇O2. Our findings suggest that the oxygen demand during squatting is notably substantial, which may vary according to the training status.

Low-Load Resistance Exercise With Blood Flow Restriction Versus High-Load Resistance Exercise on Hamstring Muscle Adaptations in Recreationally Trained Men.

Kamiş, O, Gürses, VV, Şendur, HN, Altunsoy, M, Pekel, HA, Yıldırım, E, and Aydos, L. Low-load resistance exercise with blood flow restriction vs. high-load resistance exercise on hamstring muscle adaptations in recreationally trained men. J Strength Cond Res XX(X): 000-000, 2024-Low-load resistance exercise with blood flow restriction (BFR-RE) has been suggested as a viable alternative exercise for traditional high-load resistance exercise (HL-RE). However, very little is known about hamstring muscle thickness, stiffness, and strength after BFR-RE. This study aimed to compare the effects of 6 weeks of BFR-RE and HL-RE on hamstring muscle thickness, stiffness, and strength. Twenty-nine recreationally trained men were pair matched and randomly assigned to the BFR-RE (n = 15) and HL-RE (n = 14) groups. The BFR-RE groups performed bilateral lying leg curl exercise (30-15-15-15 reps, 30-second rest between the sets, 30% 1RM) with BFR cuffs (60% of limb occlusion pressure), whereas HL-RE performed the same exercise (3 × 12 reps, 90-second rest between the sets, 70% 1RM) without BFR cuffs. Hamstring muscle thickness, muscle stiffness, isokinetic muscle strength, and 1RM were assessed at baseline and follow-up after completing a 6-week resistance exercise program (3× a week). Hamstring muscle thickness was assessed by ultrasonography, whereas muscle stiffness was evaluated by shear wave elastography. Isokinetic dynamometry and a 1RM strength test were used to determine muscular strength before and after the exercise program. Statistical significance was set at p < 0.05. No significant effect was found for hamstring muscle strength, thickness, and stiffness for group and group × time interaction, and only a significant main effect of time (p < 0.001) was observed for all outcomes. Both groups experienced significant improvements for all outcomes from baseline to follow-up without any between-group differences. In conclusion, results revealed that BFR-RE can provide similar hamstring muscle strength, thickness, and stiffness compared with HL-RE.

Microvascular Reactivity Is Greater Following Blood Flow Restriction Resistance Exercise Compared with Traditional Resistance Exercise.

Perlet, MR, Hosick, PA, Licameli, N, and Matthews, EL. Microvascular reactivity is greater following blood flow restriction resistance exercise compared with traditional resistance exercise. J Strength Cond Res XX(X): 000-000, 2024-Chronic blood flow restriction (BFR) resistance exercise can improve muscular strength, hypertrophy, and microvasculature function, but the acute microvascular effects are unknown. We aimed to test the effects of acute BFR resistance exercise on postexercise microvascular reactivity in an exercising muscle and nonexercising muscle compared with traditional resistance exercise (TRE). Twenty-five adults (men = 14, women = 11, age: 22 ± 3 years, body mass: 71.69 ± 14.49 kg, height: 170 ± 10 cm) completed barbell back squat 1-repetition maximum (1RM) testing followed by 2 randomized and counterbalanced resistance exercise visits separated by ≥48 hours. The 2 visits involved either BFR (4 sets of 30-15-15-15 repetitions at 30% 1RM, with 60-second rest intervals) or TRE (4 sets of 10 repetitions at 70% 1RM, 60-second rest intervals). During each exercise visit, a pre- and postbarbell back squat vascular occlusion test was performed using near-infrared spectroscopy to measure skeletal muscle oxygen (SmO2) in the vastus lateralis (VL) and flexor carpi radialis (FCR). Two-way repeated-measures ANOVA found an interaction effect (p = 0.020) for SmO2 reactivity in the VL. Post hoc analysis found greater reactive hyperemia postexercise in the VL for the BFR condition (p < 0.001) but not the TRE condition (p ≥ 0.05). There were no time, condition, or interaction effects (all p > 0.05) for the same analysis in the FCR. This analysis suggests that BFR, but not TRE, lead to acutely improved microvasculature function. Moreover, it suggests that the effects of BFR resistance exercise are local to the exercised or occluded limb and not systemic.

The Effects of Interval and Traditional Resistance Exercise on Hormonal Control of Adipose-tissue Lipolysis in Healthy Young Men

Purpose: Lipolysis is regulated by lipolytic hormones, like insulin, cortisol, growth Hormone (GH), and catecholamines. Unregulated lipolysis results in the accumulation of free fatty acids (FFAs), leading to dysfunction of cells and death. Thus, the main aim of this study was to determine the effects of interval and traditional resistance exercise on hormonal control of adipose-tissue lipolysis in healthy young men. Methods: Twelve healthy males (Mean ± SD; age, 25.5 ± 3.1 years; Body mass index, 24.2 ± 2.0 kg/m2) performed tradition resistance exercise (TRE) at 80% of 1RM (3 sets of 6 repetitions) with 2 min passive recovery, and an interval resistance exercise (IRE) trial at 60% of 1RM (3 sets of 6 repetitions) followed by active recovery (1 set of 6 repetitions at 20% of 1RM). Three blood samples were taken before and immediately after exercise, and after one-hour recovery and were analyzed to measure epinephrine, norepinephrine, cortisol, and GH. Results: Statistical analyses of the data revealed that concentrations of cortisol and GH increased in response to resistance exercise and significantly decreased (p &lt; 0.05) during the recovery period. Although there were no significant differences between the two protocols for cortisol concentration, GH increases following IRE were profoundly higher than TRE protocol. Epinephrine and norepinephrine increased (p &lt; 0.05) in response to both resistance exercise trials, though, no between-group differences were found for these variables. Conclusion: The results of our study showed increases in GH, cortisol, epinephrine, and norepinephrine in two resistance exercise protocols which may lead to increases in fat oxidation.

Effects of unstable load vs stable load on muscle activation and bar velocity during a bench press

Unstable load (UL) resistance exercises have gained popularity due to the potential to increase strength and neural development compared to traditional resistance exercises (Costello, 2022, J Strength Cond Res, 36, 881-887). It is assumed that training with an UL will increase the recruitment and activation of stabilising muscles, which is beneficial for daily activities and sport performance Kohler et al. (2010, J Strength Cond Res, 24, 313-321). Despite the recent increase in popularity, there is a limited amount of research that has been conducted using a UL and its impact on primary mover muscle activity. The purpose of this study was to investigate if a UL increases muscle activity of primary movers (pectoralis major sternocostal head [PEC] and triceps brachii long head [TRI]) during a bench press compared to a stable load (SL), measured via a Biopac electromyography (EMG) device. Additionally, bar velocity (m/s) using a GymAware device was compared between both UL and SL conditions. Following ethical approval, thirteen resistance-trained males were recruited (age = 21 ± 2 years; height = 178 ± 3 cm; mass = 79 ± 12 kg). Participants attended a familiarisation session, where 1RM and EMG maximum voluntary contraction (MVC) were determined. Following this, participants took part in a randomized crossover design at pre-determined loads. For the SL trial, participants performed 3 sets of 8 repetitions at 65% 1RM using a standard Olympic barbell. The US trial followed an identical protocol; however, an earthquake bar was loaded with 50% 1RM. The two-way repeated measures ANOVA revealed a significant interaction effect for the PEC activation, where there was an increase during UL but not SL condition (P = 0.001, ŋ2 = 0.633). No difference was found in the TRI between conditions (P &gt; 0.05). There was a significant 17% loss in velocity in the UL condition (P = 0.022, ŋ2 = 0.273). A significant difference was revealed in the eccentric phase for the UL condition (P = 0.001, ŋ2 = 0.473). In conclusion, muscle activation was increased in the pectoralis major muscle during the UL compared to SL resistance training. There was also an increase in velocity loss during the UL. In addition, the time of the eccentric phase was significantly longer during the UL condition. Therefore, despite the reduction in intensity, a UL may elicit greater activation of primary movers when compared to traditional resistance training alone.

Resistance Training with Instability Does Not Hamper Total Training Volume and Muscle Strength Gains in Older Adults: a Secondary Analysis from REI Study.

Resistance training with instability (REI) emerged as a promising training modality for older adults aiming to counteract age-related changes. We compared the effects of 12 weeks of REI and traditional resistance exercise (RE) on muscle strength in older adults with cognitive impairment. We further explored if total training volume (TTV) significantly differs among training groups. This is a secondary analysis of the REI study. Participants were randomly assigned to REI (n=22) or RE (n=23). RE protocol involved moderate-intensity, free-weight, and machines-based resistance exercises (3 sets, 10-15 repetitions). REI received a similar training protocol, in which exercises were simultaneously performed with instability/unstable devices (e.g., squat exercise under a foam pad or Bosu® ball). Maximal isometric strength and isokinetic parameters were assessed at baseline and after completion of a 12-week intervention through a hydraulic handgrip and isokinetic dynamometer, respectively. TTV (sets × repetitions × load) was computed based on external training load over the 12 weeks. No differences were observed between groups (p=.35) after the intervention. Over 12 weeks, REI and RE improved isometric handgrip strength (p<.001) and isokinetic performance (p=.04). We also did not find differences in the TTV between training groups (p=.28). We demonstrated that both REI and RE training induced similar gains in muscle strength. Combining unstable surfaces/instability devices did not hamper TTV, which may have clinical applications in the context of exercise for older adults.

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

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.

Exercise Technique: The Landmine Rotation

ABSTRACTThe landmine rotation is a multipurpose, total body, strength and power exercise that bridges the gap between traditional resistance exercise and rotational sport specificity. This article describes proper landmine rotation technique, outlines several variations, and offers programming recommendations.

Fatigue Alleviation by Low-Level Laser Preexposure in Ischemic Neuromuscular Electrical Stimulation.

Despite its susceptibility to muscle fatigue, combined neuromuscular electrical stimulation (NMES) and blood flow restriction (BFR) are effective regimens for managing muscle atrophy when traditional resistance exercises are not feasible. This study investigated the potential of low-level laser therapy (LLLT) in reducing muscle fatigue after the application of combined NMES and BFR. Thirty-six healthy adults were divided into control and LLLT groups. The LLLT group received 60 J of 850-nm wavelength LLLT before a training program of combined NMES and BFR of the nondominant extensor carpi radialis longus (ECRL). The control group followed the same protocol but received sham laser therapy. Assessments included maximal voluntary contraction, ECRL mechanical properties, and isometric force tracking for wrist extension. The LLLT group exhibited a smaller normalized difference in maximal voluntary contraction decrement (-4.01 ± 4.88%) than the control group (-23.85 ± 7.12%) ( P < 0.001). The LLLT group demonstrated a smaller decrease in muscle stiffness of the ECRL compared with the control group, characterized by the smaller normalized changes in frequency ( P = 0.002), stiffness ( P = 0.002), and relaxation measures ( P = 0.011) of mechanical oscillation waves. Unlike the control group, the LLLT group exhibited a smaller posttest increase in force fluctuations during force tracking ( P = 0.014), linked to the predominant recruitment of low-threshold MU ( P < 0.001) without fatigue-related increases in the discharge variability of high-threshold MU ( P > 0.05). LLLT preexposure reduces fatigue after combined NMES and BFR, preserving force generation, muscle stiffness, and force scaling. The functional benefits are achieved through fatigue-resistant activation strategies of motor unit recruitment and rate coding.

Greater glycemic control following low-load, high-repetition resistance exercise compared with moderate-intensity continuous exercise in males and females: a randomized control trial.

Exercise has long been known for its beneficial effects on insulin sensitivity (IS) and glucose handling with both moderate-intensity continuous (MIC) exercise and resistance exercise (RE) inducing beneficial effects. In recent years, low-load, high-repetition (LLHR) RE has emerged as a strategy to increase muscle mass and strength to levels similar to traditional RE; however, the effects of LLHR RE on glucose handling has yet to be investigated. The purpose of this trial was to compare the acute effects of LLHR RE to MIC exercise on post-exercise glycemic control and insulin sensitivity in males and females. Twenty-four (n=12/sex) participants completed acute bouts of MIC exercise (30 min at 65% V̇O₂peak) and LLHR (3 circuits, 6 exercises/circuit, 25-35 repetitions/exercise/circuit) matched for time with muscle biopsies immediately pre and post exercise and an oral glucose tolerance test (OGTT) 90 min following exercise. Blood glucose concentrations (p=0.002, ηp 2=0.37), glucose AUC (p=0.002, ηp 2=0.35) and max glucose concentration (p=0.003, ηp 2=0.34) were lower during the post exercise OGTT following LLHR RE compared to MIC exercise. There was a main effect of trial on TBC1D1 Ser237 phosphorylation (p=0.04, ηp 2=0.19) such that it was greater following MIC exercise compared to LLHR RE. Furthermore, phosphorylated ACC Ser79 increased following MIC exercise with no change following LLHR RE (p<0.001, ηp 2=0.50). Phosphorylation of PTEN Ser380 was greater in males than females during LLHR RE (p=0.01, ηp 2=0.27). These findings suggest that LLHR RE is a feasible exercise modality to improve post-exercise glycemic control in both males and females. Trial registration number: NCT06217679.

Heavier loads in flywheel exercise induce greater post-activation performance enhancement in countermovement jumps compared to heavy Smith machine squats in males.

We evaluated the effects of post-activation performance enhancement through flywheel exercise with varying inertial loads compared to traditional resistance exercise on countermovement jump performance and muscle recruitment. In a randomized crossover design, 13 trained men completed four main experimental trials after three familiarization sessions. These conditions included a traditional trial consisting of 5 sets of 1 repetition using the Smith machine (SM) squat at 90% 1RM, and three flywheel ergometer trials. Each flywheel protocol consisted of 3 sets of 8 repetitions with 3-minute rest intervals between sets, utilizing one of three inertial loads (0.0465, 0.0784, and 0.1568 kg · m2 for light, moderate, and heavy, respectively). Participants performed countermovement jumps before (baseline), immediately after (0 minute), and at the fourth (+4 minutes), eighth (+8 minutes), and twelfth (+12 minutes) minute following exercise. Compared to baseline, jump height was higher at +4 minutes for SM squats (p = 0.009). All flywheel conditions exhibited higher jump heights at +4 minutes (p < 0.05), +8 minutes (p < 0.001), and +12 minutes (p < 0.001) compared to baseline. Additionally, moderate and heavy loads resulted in higher jump heights at 0 minute (both p < 0.001). Integrated electromyographic activity values, a proxy for muscle recruitment, were significantly higher for the gluteus maximus muscle at both +8 minutes and +12 minutes for moderate (both p = 0.004) and heavy loads (p ≤ 0.002) compared to SM squats. Overall, flywheel protocols produce greater post-activation performance enhancement, extend the time window for improvement, and recruit more active musculature compared to heavy-load SM squats, particularly with heavier loads acting as a stronger preload stimulus.

Muscle Mass and Muscle Strength Following 6 Weeks of Blood Flow Restriction Combined with Low-Intensity Strength Training in Overweight Adolescents

Background and Study purpose. Blood flow restriction training is a new training technique that involves low-intensity exercise and can generate physiological changes equivalent to high-intensity exercise. The aim of this study is to assess the impact of blood flow restriction in conjunction with low-intensity resistance exercise on muscle mass and muscle strength among overweight adolescents, in comparison to conventional resistance exercise. Materials and methods. The study involved two randomized groups: an experimental group, which performed 40% of one repetition maximum (1RM) resistance exercise combined with 60% of arterial occlusion pressure (AOP), and a traditional resistance exercise group, which performed 70% of 1RM resistance exercise. All participants underwent pre-test and post-test evaluations for body composition, 1RM, and muscle circumference. The training program lasted for six weeks and consisted of upper and lower body training, including exercises such as leg press, leg curl, arm curl, and arm extension. Results. The group that underwent low-load blood flow restriction (LLBFR) training showed a notable increase in muscle mass (p&lt;0.049) as well as arm and leg circumference (p&lt;0.047 and p&lt;0.046, respectively) compared to before the training program, similar to the results of high-intensity resistance exercise. Conclusions. Combining blood flow restriction with low-intensity resistance training is a potentially effective approach to increase muscle size and strength, especially in overweight adolescents. Moreover, this type of training can decrease the amount of exercise load, making it a feasible option for individuals who may not tolerate high loads due to certain medical conditions or other limitations.

The effects of low-intensity resistance training with blood flow restriction versus traditional resistance exercise on lower extremity muscle strength and motor functionin ischemic stroke survivors: a randomized controlled trial

ABSTRACT Background Blood flow restriction (BFR) training can temporarily reduce cortical GABA concentrations and increase the size of motor volleys to deafferented muscles, which can promote motor recovery in stroke survivors. Objective To determine the effect of low-intensity resistance training with BFR (LIRT-BFR) on lower extremity muscle strength, balance, functional mobility, walking capacity, gait speed, anxiety, and depression in stroke survivors and to compare the results with high-intensity resistance training (HIRT). Method It was a two-arm, single-blinded, randomized controlled trial in which 32 ischemic stroke participants were randomly allocated to LIRT-BFR or HIRT group. The LIRT-BFR group received low load resistance training (40% of 1-Repetition Maximum (1-RM)) with BFR, whereas HIRT group received high load resistance training (80% of 1-RM). The 6-Minute Walk Test (6-MWT), five-time sit-to-stand test (5TSTST), Timed Up and Go (TUG) test, and Barthel index were the primary outcome measures. The secondary outcome measures included gait speed (m/s), stride length (cm), cadence (steps/min), and Hospital Anxiety and Depression. Results All the primary and secondary outcome measures were significantly improved in both groups (p < 0.05). The LIRT-BFR group showed a slightly greater, but non-significant, improvement as compared to the HIRT group in terms of mean change observed in 6-MWT (81 m vs 62 m), 5TSTST (−5.27 vs −4.81), gait speed (0.19 vs 0.12), stride length (18 vs 13), and cadence (8 vs 6). No adverse event was reported. Conclusion LIRT-BFR produced a significant improvement in muscle strength, balance, walking capacity, and anxiety and depression in ischemic stroke patients, and the improvement are comparable to HIRT. Clinical Trial Registration NCT05281679

Comparable effects of interval and traditional resistance exercise on lipolysis and insulin concentration in healthy young men

Comparable effects of interval and traditional resistance exercise on lipolysis and insulin concentration in healthy young men

Effect of 12-Week Resistance Training with Blood Flow Restriction on Arterial Stiffness in Octogenarian People with Low Gait Speed: A Randomized Controlled Trial

Aim: Aging is associated with loss of muscle mass and strength. Low-Intensity Resistance Exercise with Moderate Blood-Flow Restriction (LIRE-BFR) improves these outcomes, but the long-term effect on arterial stiffness and safety in elderly people with low gait speed is unknown. Methods: This is a parallel, randomized controlled clinical study with 12 older adults (3 men; 9 women; 84.0 [76.0; 87.5] years old) who completed a 12-week training of traditional resistance exercise (TRE; n=6) or LIRE-BFR (n=6). All participants were evaluated at baseline and after 12 weeks by carotid-femoral aortic Pulse Wave Velocity (PWV). Results: After 12 weeks of interventions, PWV decreased in TRE group (-2.9 [-8.1; 2.4] m/s) and increased slightly in LIRE-BFR group (1.1 [-3.2; 5.3] m/s) but no differences were observed between the groups (p=0.21 for group; Hedge’s g: 0.52). Mean blood pressure was similar between TRE (86.2 [81.8; 90.9] to 85.8 [76.5; 96.3] mmHg) and LIRE-BFR (92.4 [82.1; 103.9] to 85.5 [79.2; 92.4] mmHg, p=0.462 for interaction). Gait speed increased significantly after 12 weeks in both groups (p&lt;0.001 for time) with no differences between them (p=0.693 for groups). Conclusions: Compared to TRE, LIRE-BFR increased PWV slightly, while gait speed increased similarly in both training modalities. Larger clinical trials including elderly people with low gait speed are needed to determine the clinical impact of these findings.

The effects of type of recovery in resistance exercise on responses of platelet indices and hemodynamic variables.

To examine the effects of two different volume-matched resistance exercise (RE) recovery protocols (passive and active) on platelet indices and hemodynamic variables. Twelve Healthy participants (mean ± SD; 25 ± 3 yrs) completed a traditional resistance exercise (TRE) protocol that included three sets of six repetitions at 80% one repetition maximum (1RM) with two minutes passive recovery between sets, exercises and an interval resistance exercise (IRE) protocol that included three sets of six repetitions at 60%1RM followed by active recovery including six repetitions of the same exercise at 20%1RM. Blood samples for multiple platelet indices were taken before the protocols, immediately-post (IP), and after 1-hour recovery. Hemodynamic variables were measured before, IP, and every five minutes during recovery. Mean platelet volume and platelet large cell ratio P_LCR decreased from baseline to recovery. Heart rate (HR) and rate pressure product (RPP) were augmented at IP following IRE compared to TRE. HR was significantly elevated for 20 minutes after both RE protocols, and RPP recovered by five minutes. Systolic blood pressure was increased at IP compared to baseline and all recovery time points for both RE protocols. Our research demonstrated that both RE protocols, produced transient increases in platelet indices (MPV, and P_LCR) and hemodynamic variables (SBP, HR, and RPP), all of which returned to baseline within an hour. Notably, the IRE protocol elicited a greater increase in HR and RPP compared to the TRE protocol.

Intentionally Slow Concentric Velocity Resistance Exercise and Strength Adaptations: A Meta-Analysis.

Hermes, MJ and Fry, AC. Intentionally slow concentric velocity resistance exercise and strength adaptations: a meta-analysis. J Strength Cond Res 37(8): e470-e484, 2023-Intentionally slow-velocity resistance exercise (ISVRE) is suggested by some to be equally or more effective than fast or traditional velocities for increasing muscular strength. The purpose of this meta-analysis was to assess the effect ISVRE has on strength adaptations compared with faster or traditional velocities, with subgroup analyses exploring age, sex, and training status as confounding factors on the influence of velocity on strength adaptation. Eligible studies (n = 24) were required to be chronic (multiple weeks) randomized or nonrandomized comparative studies using dynamic constant external resistance for training and testing, and pre-post strength assessments. All studies examined healthy individuals (n = 625; fast or traditional n = 306, intentionally slow n = 319). A random-effects meta-analysis indicated a significant (p ≤ 0.05) effect in favor of fast training (effect size [ES] = 0.21, 95% confidence interval [CI] = 0.02-0.41, p = 0.03). Publication bias was noted through trim and fill analysis, with an adjusted effect size estimate of 0.32 (p < 0.001). Subgroup analyses indicated no difference between trained and untrained subjects (QM = 0.01, p = 0.93), and no difference between older and younger subgroups (QM = 0.09, p = 0.77), despite younger favoring faster (ES = 0.23, p = 0.049) and older not favoring either velocity (ES = 0.16, p = 0.46). Subgroup analysis also indicated women favored faster training (ES = 0.95, p < 0.001) in comparison to men (ES = 0.08, p = 0.58). Contrary to some previous reviews, these results indicate that chronic fast or traditional velocity resistance exercise increases muscular strength to a greater degree than ISVRE training. Resistance training velocity must be considered if strength is a desired outcome.

Myoelectric activity during electromagnetic resistance alone and in combination with variable resistance or eccentric overload

The purpose of this study was to compare the effects of electromagnetic resistance alone, as well as in combination with variable resistance or accentuated eccentric methods, with traditional dynamic constant external resistance exercise on myoelectric activity during elbow flexion. The study employed a within-participant randomized, cross-over design whereby 16 young, resistance-trained male and female volunteers performed elbow flexion exercise under each of the following conditions: using a dumbbell (DB); using a commercial electromagnetic resistance device (ELECTRO); variable resistance (VR) using a setting on the device that attempts to match the level of resistance to the human strength curve, and; eccentric overload (EO) using a setting on the device that increases the load by 50% on the eccentric portion of each repetition. Surface electromyography (sEMG) was obtained for the biceps brachii, brachioradialis and anterior deltoid on each of the conditions. Participants performed the conditions at their predetermined 10 repetition maximum. " The order of performance for the conditions was counterbalanced, with trials separated by a 10-min recovery period. The sEMG was synced to a motion capture system to assess sEMG amplitude at elbow joint angles of 30°, 50°, 70°, 90°, 110°, with amplitude normalized to the maximal activation. The anterior deltoid showed the largest differences in amplitude between conditions, where median estimates indicated greater concentric sEMG amplitude (~ 7–10%) with EO, ELECTRO and VR compared with DB. Concentric biceps brachii sEMG amplitude was similar between conditions. In contrast, results indicated a greater eccentric amplitude with DB compared to ELECTRO and VR, but unlikely to exceed a 5% difference. Data indicated a greater concentric and eccentric brachioradialis sEMG amplitude with DB compared to all other conditions, but differences were unlikely to exceed 5%. The electromagnetic device tended to produce greater amplitudes in the anterior deltoid, while DB tended to produce greater amplitudes in the brachioradialis; amplitude for the biceps brachii was relatively similar between conditions. Overall, any observed differences were relatively modest, equating to magnitudes of ~ 5% and not likely greater than 10%. These differences would seem to be of minimal practical significance.

Comparable effects of circuit and traditional resistance exercise on platelet α2bβ3 receptor and platelet activation and function.

Resistance exercise induces thrombocytosis and increases platelet activation and function. These changes might be related to exercise variables including exercise intensity and type. We compared the effects of traditional resistance exercise (TRE) and circuit resistance exercise (CRE) on cellular markers of platelet activation and function. In this crossover study ten healthy male (mean±SD: age, 25.6±2.4 years) subjects performed TRE encompassed 3 sets of 10 repetitions at 100% of 10-RM (10 repetition maximum) for 6 exercises, and CRE protocols included 3 sets of 10 repetitions at 100% of 10-RM for all 6 exercises consecutively, in two separate weeks. To measure platelet indices, PAC1, CD41a, CD42b and CD62P three blood samples were taken before, immediately after exercise, and after 30 min recovery. Lactate concentration, blood pressure, platelet count (PLT), and mean platelet volume (MPV) were significantly (p < 0.05) increased following both resistance exercise trials. Significant increases in PAC1, and CD62P; and significant reductions for CD42b and CD41a were detected following both REs (p < 0.05). However, changes in PAC1 and CD62P were significantly different between the two protocols (p < 0.05), with higher increases detected following CRE. Acute RE increases platelet indices and platelet activation; and that CRE results in higher platelet activation than TRE, probably due to exercise-induced increases in shear stress.