Single vs. Multi-Joint Resistance Exercises: Effects on Muscle Strength and Hypertrophy

Musculoskeletal modelling based estimates of load dependent relative muscular effort during resistance training exercises

The purpose of this study was to investigate the relative muscular effort (RME) of the hip and knee extensor and ankle plantarflexor muscle groups during the back squat (BS) and split squat (SS) exercises across four external load conditions. Motion capture and force plate data were collected as participants performed the BS and SS at 0%, 25%, 50%, and 75% of their body-mass. These data were used to calculate net joint moments (NJM) at the hip, knee, and ankle of the front leg during the SS and the matched leg during the BS. A musculoskeletal model, which accounted for force-length-velocity properties of 52 muscles, was used to estimate the maximal possible NJM (NJMmax) of the hip and knee extensor and ankle plantarflexor muscle groups. RME was calculated as the ratio between NJM and NJMmax, and compared across exercises and loads. The results indicated that while hip extensor RME increased across all loads, the increases in hip extensor RME were disproportionately greater during the SS at loads of 50% and 75%. Knee extensor RME increased linearly across loads and did not differ between exercises. These results provide coaches and athletes with detailed information about how to optimise resistance training specificity.

Resistance Exercise Sessions Comprising Multijoint vs. Single-Joint Exercises Result in Similar Metabolic and Hormonal Responses, But Distinct Levels of Muscle Damage in Trained Men

ABSTRACT

Barbosa, PH, Bueno de Camargo, JB, Jonas de Oliveira, J, Reis Barbosa, CG, Santos da Silva, A, Dos-Santos, JW, Verlengia, R, Barreira, J, Braz, TV, and Lopes, CR. Resistance exercise sessions comprising multijoint vs. single-joint exercises result in similar metabolic and hormonal responses, but distinct levels of muscle damage in trained men. J Strength Cond Res 38(5): 842-847, 2024-Resistance-type exercise (RE) elicits distinct acute metabolic and hormonal responses, which can be modulated by the manipulation of training variables. The purpose of this study was to compare the metabolic (blood lactate and estimated lactic anaerobic system energy expenditure) and hormonal (growth hormone [GH]) responses to RE sessions composed exclusively of multijoint (MULTI) or single-joint (SINGLE) exercises. Assessments of creatine kinase (CK) levels were also performed. In a crossover design, 10 recreationally resistance-trained men (age: 26.9 ± 3.0 years, total body mass: 83.2 ± 13.8 kg; height: 176 ± 7.0 cm; training experience: 5.5 ± 2.4 years) were randomly submitted to both protocols. Blood collections were made pre, 3 minutes after, and 36 hours after each experimental session. No significant difference between MULTI vs. SINGLE was observed for the rises in blood lactate (p = 0.057) and GH (p = 0.285) levels. For CK, a significant difference between the protocols was noted, in which MULTI resulted in significant rises after 3 minutes (p = 0.017) and 36 hours (p = 0.043) compared with SINGLE. In conclusion, the findings of this study suggest that resistance-trained individuals display similar metabolic and hormonal responses when performing MULTI and SINGLE exercise protocols. Also, RE sessions comprising MULTI exercises induce a higher magnitude of muscle damage, which may require a longer recovery period compared with SINGLE.

Resistance Training before, during, and after COVID-19 Infection: What Have We Learned So Far?

At the end of 2019, a severe acute respiratory syndrome caused by SARS-CoV-2 started a pandemic, leading to millions of deaths and many important political and social changes. Even in the absence of contamination, the mobility reduction, social distancing and closing of exercise facilities negatively affected physical activity and conditioning, which is associated with muscle atrophy, loss of muscle strength, and reductions in functional capacity. In cases of infection, it has been shown that increased physical capacity is associated with decreased hospitalization and mortality risk. Although millions of people have died from COVID-19, most contaminated individuals survived the infection, but carried different sequelae, such as the severe loss of physical function and a reduced quality of life. Among different physical exercise models that might help to prevent and treat COVID-19-related conditions, resistance training (RT) might be particularly relevant. Among its benefits, RT can be adapted to be performed in many different situations, even with limited space and equipment, and is easily adapted to an individual's characteristics and health status. The current narrative review aims to provide insights into how RT can be used in different scenarios to counteract the negative effects of COVID-19. By doing this, the authors expect to provide insights to help deal with the current pandemic and similar events the world may face in the future.

Single-Joint Exercise Results in Higher Hypertrophy of Elbow Flexors Than Multijoint Exercise

ABSTRACT

Mannarino, P, Matta, T, Lima, J, Simão, R, and Freitas de Salles, B. Single-Joint Exercise Results in Higher Hypertrophy of Elbow Flexors Than Multijoint Exercise. J Strength Cond Res 35(10): 2677-2681, 2021-Recent data suggest that single-joint exercises are unnecessary to maximize the resistance training (RT) results in novice to advanced individuals. However, the present literature is still inconsistent on this topic and controversy arises. The aim of this study was to compare the effects of the unilateral dumbbell row (DR) (multiple-joint) vs. unilateral biceps curl (BC) (single-joint) exercises on strength and elbow flexors muscle thickness (MT). Ten untrained men were assigned to an 8-week RT program for elbow flexors, one arm performing DR and the other performing BC in a within-subject design. After a familiarization, pretraining MT was measured using an ultrasound (US) technique, and strength was tested using 10 repetition maximum (10RM) tests. After pretesting, 8 weeks of RT (4-6 sets, 8-12 repetitions to concentric failure, 2 sessions per week) was performed. Post-testing was conducted in the same order as pretesting 48 and 72 hours after the last session. Single-joint BC exercise resulted in higher hypertrophy of elbow flexors (11.06%) than the DR (5.16%) multijoint exercise after 8 weeks of RT (p = 0.009). The 10RM improvement was higher for DR in DR-trained arm, whereas 10RM for BC was higher in BC-trained arm. The single-joint exercise resulted in higher hypertrophy of the elbow flexors than multijoint exercise after 8 weeks of RT, whereas strength improvements were greater in accordance with specificity of RT exercise. Therefore, in RT prescription for elbow flexors hypertrophy, single-joint exercises such as BC should be emphasized.

Equating Resistance-Training Volume Between Programs Focused on Muscle Hypertrophy

Calculating resistance-training volume in programs focused on muscle hypertrophy is an attempt to quantify the external workload carried out, then to estimate the dose of stimulus imposed on targeted muscles. The volume is usually expressed in some variables that directly affected the total training work, such as the number of sets, repetitions, and volume-load. These variables are used to try to quantify the training work easily, for the subsequent organization and prescription of training programs. One of the main uses of measures of volume quantification is seen in studies in which the purpose is to compare the effects of different training protocols on muscle growth in a volume-equated format. However, it seems that not all measures of volume are always appropriate for equating training protocols. In the current paper, it is discussed what training volume is and the potentials and shortcomings of each one of the most common ways to equate it between groups depending on the independent variable to be compared (e.g., weekly frequency, intensity of load, and advanced techniques).

Practical Recommendations Relevant to the Use of Resistance Training for COVID-19 Survivors

The novel coronavirus disease (COVID-19) has emerged at the end of 2019 and caused a global pandemic. The disease predominantly affects the respiratory system; however, there is evidence that it is a multisystem disease that also impacts the cardiovascular system. Although the long-term consequences of COVID-19 are not well-known, evidence from similar diseases alerts for the possibility of long-term impaired physical function and reduced quality of life, especially in those requiring critical care. Therefore, rehabilitation strategies are needed to improve outcomes in COVID-19 survivors. Among the possible strategies, resistance training (RT) might be particularly interesting, since it has been shown to increase functional capacity both in acute and chronic respiratory conditions and in cardiac patients. The present article aims to propose evidence-based and practical suggestions for RT prescription for people who have been diagnosed with COVID-19 with a special focus on immune, respiratory, and cardiovascular systems. Based on the current literature, we present RT as a possible safe and feasible activity that can be time-efficient and easy to be implemented in different settings.

Multi- and Single-Joint Resistance Exercises Promote Similar Plantar Flexor Activation in Resistance Trained Men

The present study aimed to compare soleus, lateral, and medial gastrocnemius muscles activation during leg press and calf raise exercises in trained men. The study involved 22 trained men (27.1 ± 3.6 years, 82.7 ± 6.6 kg, 177.5 ± 5.2 cm, 3.6 ± 1.4 experience years) who performed one set of each exercise using a 10-repetition maximum (10RM) load in a counterbalanced randomized order and separated by 10 min of rest. The electromyographic signal was measured for the three major plantar flexors: soleus, medial, and lateral gastrocnemius. A comparison between exercises showed that the mean adjusted by peak values during the leg press were 49.20% for the gastrocnemius lateralis, 51.31% for the gastrocnemius medialis, and 50.76% for the soleus. Values for calf raise were 50.70%, 52.19%, and 51.34% for the lateral, medial gastrocnemius, and soleus, respectively. There were no significant differences between exercises for any muscle (lateral gastrocnemius (p = 0.230), medial gastrocnemius (p = 0.668), and soleus (p = 0.535)). The present findings suggest that both leg press and calf raises can be used with the purpose to recruit triceps surae muscles. This bring the suggestion that one can chose between exercises based on personal preferences and practical aspects, without any negative impact on muscle activation.

Multi-joint vs. Single-joint Resistance Exercises Induce a Similar Strength Increase in Trained Men: A Randomized Longitudinal Crossover Study

The type of exercise is a relevant resistance training-variable that might be manipulated in order to induce significant increases in muscle strength. The aim of this study was to analyze the influence of multi-joint vs single-joint resistance exercises on maximal strength. Sixteen resistance-trained men (age: 23.1 ± 4.4 years; body mass: 86.0 ± 12.8; height: 177.9 ± 6.4 cm; training experience: 4.2 ± 3.4 years) performed one of the following training protocols for six weeks: MULTI, consisting of only multi-joint exercises or SINGLE, consisting of only single-joint exercises. Subjects were then submitted to a three-week washout period, before being submitted to the other protocol for another six weeks. A linear periodization model was adopted in which external load was increased and the repetition range was decreased every two weeks. Maximal dynamic strength of bench press (1RM_BENCH) and squat exercises (1RM_SQUAT), a percentage variation of total load lifted (ΔTLL) and internal training load (ITL) were measured. Similar increases in 1RM_BENCH (MULTI: 10.8%, p < 0.001; SINGLE: 5.5%, p < 0.001) and 1RM_SQUAT (MULTI: 19.7%, p < 0.001; SINGLE: 19.0%, p < 0.001) were observed after the MULTI and SINGLE protocols. A decrease in TLL was detected for both exercise protocols; however, the SINGLE protocol induced a greater decrease, compared to the MULTI protocol (-35 ± 11% vs -42 ± 5%, respectively; p = 0.026). A greater ITL for the MULTI was observed when compared to the SINGLE (12.1%; p < 0.001). In conclusion, resistance training protocols with different exercise modalities seem to produce similar strength increases in resistance-trained men.

Varying the Order of Combinations of Single- and Multi-Joint Exercises Differentially Affects Resistance Training Adaptations

Brandão, L, de Salles Painelli, V, Lasevicius, T, Silva-Batista, C, Brendon, H, Schoenfeld, BJ, Aihara, AY, Cardoso, FN, de Almeida Peres, B, and Teixeira, EL. Varying the order of combinations of single- and multi-joint exercises differentially affects resistance training adaptations. J Strength Cond Res 34(5): 1254-1263, 2020-Our study aimed to compare the effects of multi-joint (MJ) and single-joint (SJ) exercises, either isolated or in combination, and in different orders, on cross-sectional area (CSA) of the pectoralis major (PM) and different heads of the triceps brachii (TB), as well as on the one-repetition maximum (1-RM) in the bench press and lying barbell triceps press. Forty-three young men were randomly assigned to one of 4 possible RT protocols: barbell bench press plus lying barbell triceps press (MJ + SJ, n = 12); lying barbell triceps press plus barbell bench press (SJ + MJ, n = 10); barbell bench press (MJ, n = 10); or lying barbell triceps press (SJ, n = 11). Results showed significant within-group increases in 1-RM bench press for MJ, MJ + SJ, and SJ + MJ but not for SJ. Conversely, significantly greater within-group increases in elbow extension 1-RM were noted for SJ, MJ + SJ, and SJ + MJ but not for MJ. Significantly greater increases in PM CSA were observed for MJ, MJ + SJ, and SJ + MJ compared with SJ. Significant increases in TB CSA were noted for SJ, MJ + SJ, and SJ + MJ, but not for MJ, without observed between-group differences. Individual analysis of TB heads showed significantly greater CSA increases in the lateral head for MJ, MJ + SJ, and SJ + MJ compared with SJ. Alternatively, significantly greater increases in the long head were observed for SJ, MJ + SJ, and SJ + MJ compared with MJ. CSA increases for the medial head were statistically similar between conditions. Our findings indicate that muscular adaptations are differentially affected by performance of MJ and SJ exercises.

Resistance Training Safety during and after the SARS-Cov-2 Outbreak: Practical Recommendations

In December of 2019, there was an outbreak of a severe acute respiratory syndrome caused by the coronavirus 2 (SARS-CoV-2 or COVID-19) in China. The virus rapidly spread into the whole world causing an unprecedented pandemic and forcing governments to impose a global quarantine, entering an extreme unknown situation. The organizational consequences of quarantine/isolation are absence of organized training and competition, lack of communication among athletes and coaches, inability to move freely, lack of adequate sunlight exposure, and inappropriate training conditions. The reduction of mobility imposed to contain the advance of the SARS-Cov-2 pandemic can negatively affect the physical condition and health of individuals leading to muscle atrophy, progressive loss of muscle strength, and reductions in neuromuscular and mechanical capacities. Resistance training (RT) might be an effective tool to counteract these adverse consequences. RT is considered an essential part of an exercise program due to its numerous health and athletic benefits. However, in the face of the SARS-Cov-2 outbreak, many people might be concerned with safety issues regarding its practice, especially in indoor exercise facilities, such as gyms and fitness centers. These concerns might be associated with RT impact in the immune system, respiratory changes, and contamination due to equipment sharing and agglomeration. In this current opinion article, we provide insights to address these issues to facilitate the return of RT practices under the new logistical and health challenges. We understand that RT can be adapted to allow its performance with measures adopted to control coronavirus outbreak such that the benefits would largely overcome the potential risks. The article provides some practical information to help on its implementation.

Effects of Horizontal and Incline Bench Press on Neuromuscular Adaptations in Untrained Young Men

The aim of the current study was to investigate the effects of horizontal and incline bench press as well as the combination of both exercises on neuromuscular adaptation in untrained young men. Forty-seven untrained men were randomly assigned to one of the three groups: 1) a horizontal bench press group (n= 15), 2) an incline bench press group (n= 15), and 3) a combination (horizontal + incline) group (n= 17). Training was conducted once a week for eight weeks, with equalized number of sets among groups. Muscle thickness, isometric strength and electromyography (EMG) amplitude of the pectoralis major were measured one week before and after the training period. There was no difference between groups for the change in horizontal bench press isometric strength (~ 10 kg increase, p=0.776) or incline bench press isometric strength (~ 11 kg increase, p=0.333). Changes in muscle thickness differed only in one of the three sites. The changes in the second intercostal space of the pectoralis major was greatest in the incline pressure group compared with the horizontal [mean difference (95% CI) of 0.62 (0.23, 1.0) cm, p=0.003] and combination groups [mean difference (95% CI) of 0.50 (0.14, 0.86) cm, p=0.008]. The change in EMG amplitude following training differed between groups in only one out of the four sites. The present results indicate that strength and conditioning professionals might consider that horizontal and incline bench press exercises, or a combination of both exercises can render similar change in general strength.

The Relationship between Isokinetic Trunk, Leg Strength and Isometric Mid-Thigh Pull Test, Counter Movement Jump in National Rowing Athletes

OBJECTIVES The purpose of this study was to analyze the relationship between isokinetic leg strength and maximum Isometric Med-Thigh Pull Test(IMTP) and maximum height of Counter Movement Jump (CMJ) in Korean national rowers.METHODS Each eight male and female athletes were participated in the study. Isometric IMTP, CMJ, and isokinetic trunk, hip, and knee strength were measured to analyze the relationship between the IMTP, CMJ and isokinetic strength. The correlation between variables was analyzed by the step-wise method of multiple regression analysis after analyzing the correlation between dependent and independent variables.RESULTS Knee, Hip and trunk isokinetic flexion and extension strength showed high correlation with maximum IMTP with the all participants. Knee extension and trunk flexion isokinetic strength showed higher correlation with IMTP. Knee extension isokinetic strength showed high correlation with CMJ.CONCLUSIONS For strengthening exercise of National rowers, ipsilateral strength balance and agonistantagonist strength balance of leg and trunk should be considered to improve performance efficiently.

Seated row and biceps curl exercises present similar acute responses on muscle thickness, arm circumference, and peak force for elbow flexors after a resistance training session in recreationally-trained subjects

BACKGROUND

The primary purpose of this study was to measure the acute effects on muscle thickness, arm circumference, and peak force between unilateral seated row and unilateral biceps curl exercises for elbow flexors after a RT session in recreationally-trained subjects.

METHODS

Fourteen resistance-trained men (25.3±2.5years, 76.5±6.4kg, 174.6±7cm) performed 6 sets of 10RM and 2-min rest for one of two exercises (unilateral seated row exercise, USR or unilateral biceps curl, UBC). Muscle thickness (MT), arm circumference (AC), and peak force (PF) were measured before 10-min (control), pre-RT session and post-RT (immediately after, 15-min and 30-min). All acute RT variables were measured during both exercises: maximal number of repetitions (MNR), total number of repetitions (TNR), time under tension (TUT), rating of perceived exertion (RPE). Two-way ANOVAs were used to test differences between exercises and moments with an alpha of 5%.

RESULTS

For PF, there was a significant difference between pre- and post-0 for UBC and USR (P<0.001). For AC, there were significant differences between pretest × post-0-min for both exercises (P<0.001). For MT, there were significant differences between pretest × post 0-min (P<0.001), pretest × post 15-min (P<0.001) for both exercises and pretest × post 30-min only for UBC (P=0.006).

CONCLUSIONS

Both exercises induced similar increases in AC and MT for elbow flexors and reduction in peak force.

Training specificity performing single-joint vs. multi-joint resistance exercises among physically active females: A randomized controlled trial

Resistance-training of the lower limbs can be performed using exercises moving one (single-joint exercises) or several joints (multi-joint exercises). This study compared the effects of training one multi-joint exercise (leg press) or two single-joint exercises (leg extension and kickback) on dynamic and isometric strength and the transferability of dynamic strength between exercises. Fifty-three physically active women were randomized to a multi-joint (MJ) training group (age = 21.95±0.82 years, mass = 64.85±5.76 kg, height = 167.35±2.47 cm; n = 20), single-joint (SJ) training group (age = 22.56±1.66 years, mass = 64.85±5.76 kg, height = 165.94±2.84 cm; n = 18), or a control (CON) group (age = 21.27±0.68 years, mass = 68.43±4.86 kg, height = 168.63±2.84 cm; n = 15). The training groups participated in an 8-week supervised single- or multi-joint lower limb training consisting of 18 sessions. Pre- and post-training, six repetitions maximum (RM) and maximal voluntary isometric contraction in the three exercises were assessed, along with electromyography of the superficial quadriceps muscles. Improvements in all dynamic exercises were greatest after training the specific exercises (ES = 1.26–2.14, P<0.001–0.025) and all were greater in the training groups than in the CON group (ES = 1.43–3.31, P<0.001–0.021). The SJ group improved 6RM in leg extension and kickback more than leg press (ES = 1.51 and 2.04, respectively, P<0.001), whereas the MJ group improved leg press 6RM more than kickback (ES = 1.10, P = 0.002). However, leg press and leg extension strength improved similarly in the MJ group (ES = 0.54, P = 0.072). All strength and electromyographic measures remained unchanged in the CON group (ES = 0.00–0.44, P = 0.412–0.966). Improved dynamic strength in leg press, kickback and leg extension is best attained by training the specific exercises, but both training modalities can improve strength across all exercises.

The Effects of Resistance Exercise Selection on Muscle Size and Strength in Trained Women

The study compared the effects of resistance training programs composed by multi-joint (MJ), single-joint (SJ) and the combination of multi- and single-joint (MJ+SJ) exercises on muscle strength and hypertrophy in trained women. Thirty participants were divided into groups that performed only MJ exercises, SJ exercises and MJ+SJ exercises for six months. Participants were tested for 1-repetition maximum (RM) and muscle thickness (MT) before and after the intervention. All groups showed significant gains on 1RM tests from pre- to post-training (P<0.01). However, MJ and MJ+SJ groups obtained greater gains in 1RM for the MJ exercises in comparison with the SJ group. Increases in 1RM for the SJ exercises were similar among groups, with the exception of leg curl, where the SJ group obtained greater gains than MJ and MJ+SJ. All groups obtained significant increases in MT from pre- to post-training for all muscle groups. However, MJ and MJ+SJ groups presented greater increases in gluteus maximus, quadriceps femoris and pectoralis major in comparison with the SJ group. Therefore, our results suggest that, in general, performing MJ exercises seems to be necessary to obtain optimal results from a resistance training program; however SJ might be necessary to provide optimal strength gains in knee flexion.

Resistance Training Volume Enhances Muscle Hypertrophy but Not Strength in Trained Men

Purpose

The purpose of this study was to evaluate muscular adaptations between low-, moderate-, and high-volume resistance training protocols in resistance-trained men.

Methods

Thirty-four healthy resistance-trained men were randomly assigned to one of three experimental groups: a low-volume group performing one set per exercise per training session (n = 11), a moderate-volume group performing three sets per exercise per training session (n = 12), or a high-volume group performing five sets per exercise per training session (n = 11). Training for all routines consisted of three weekly sessions performed on nonconsecutive days for 8 wk. Muscular strength was evaluated with one repetition maximum (RM) testing for the squat and bench press. Upper-body muscle endurance was evaluated using 50% of subjects bench press 1RM performed to momentary failure. Muscle hypertrophy was evaluated using B-mode ultrasonography for the elbow flexors, elbow extensors, mid-thigh, and lateral thigh.

Results

Results showed significant preintervention to postintervention increases in strength and endurance in all groups, with no significant between-group differences. Alternatively, while all groups increased muscle size in most of the measured sites from preintervention to postintervention, significant increases favoring the higher-volume conditions were seen for the elbow flexors, mid-thigh, and lateral thigh.

Conclusions

Marked increases in strength and endurance can be attained by resistance-trained individuals with just three 13-min weekly sessions over an 8-wk period, and these gains are similar to that achieved with a substantially greater time commitment. Alternatively, muscle hypertrophy follows a dose–response relationship, with increasingly greater gains achieved with higher training volumes.

Calculating Set-Volume for the Limb Muscles with the Performance of Multi-Joint Exercises: Implications for Resistance Training Prescription

Resistance training volume, determined by the number of sets performed (set-volume) is considered one of the key variables in promoting muscle hypertrophy. To better guide resistance exercise prescription for weekly per-muscle training volume, the purpose of this paper is to provide evidence-based considerations for set-volume ratios between multi-joint (MJ) and single-joint (SJ) exercises so that practitioners can better manage prescription of training volume in program design. We analyzed this topic from three primary areas of focus: (1) biomechanical and physiological factors; (2) acute research; and (3) longitudinal research. From a biomechanical and physiological standpoint, when considering force production of different muscle groups, the moment arm of a given muscle, “motor abundance”, the link between biomechanics and exercise-induced fatigue, as well as the amount of time in voluntary muscle activation, a logical rationale can be made for SJ exercises producing greater hypertrophy of the limb muscles than MJ exercises (at least from specific exercises and under certain conditions). This would mean that sets for a MJ exercise should be counted fractionally for select muscles compared to an SJ exercise (i.e., less than a 1:1 ratio) when prescribing set-volumes for given muscles. When considering results from acute studies that measured muscle activation during the performance of SJ and MJ exercises, it seems that MJ exercises are not sufficient to maximize muscle activation of specific muscles. For example, during performance of the leg press and squat, muscle activation of the hamstrings is markedly lower than that of the quadriceps. These results suggest that a 1:1 ratio cannot be assumed. Current longitudinal research comparing the effects of training with MJ vs. SJ or MJ + SJ exercises is limited to the elbow flexors and the evidence is somewhat conflicting. Until more research is conducted to derive stronger conclusions on the topic, we propose the best advice would be to view set-volume prescription on a 1:1 basis, and then use logical rationale and personal expertise to make determinations on program design. Future research should focus on investigating longitudinal hypertrophic changes between MJ and SJ in a variety of populations, particularly resistance-trained individuals, while using site-specific measures of muscle growth to more systematically and precisely compute effective individualized set-volumes.

Antioxidant Supplementation Impairs Changes in Body Composition Induced by Strength Training in Young Women

Strength training (ST) is known to promote muscle hypertrophy and body composition adaptations. However, only a few studies investigated the effects of ST combined with antioxidant supplementation (AS) on these adaptations. The aim of this study was to investigate chronic effects of ST combined with AS on fat mass (FM) and fat-free mass (FFM) of young women. In a double-blinded design, thirty-three subjects (22.9 ± 2.5 years, 57.7 ± 8.4 kg, 1.6 ± 0.6 m) were allocated into three groups: 1) vitamins (n=12), 2) placebo (n=11) and 3) control (n=10). Vitamins and placebo underwent a ST program for 10 weeks. Vitamins supplemented with vitamin C (1g/day) and E (400IU/day) during the training period. FM and FFM were assessed by DEXA. Multiple 3 x 2 (group x time) mixed-factor ANOVA with Tukey adjustment was performed to examine differences in the dependent variables. The significance level was set at P ≤ .05. Only placebo increased total FFM (34.9 ± 4.9 vs 36.3 ± 4.8 kg, P<0.05) and decreased total FM (21.8 ± 7.8 vs 21.0 ± 8.3 kg, P<0.05) after training for 10 weeks. Moreover, only placebo presented a significantly greater FFM percent change from pre to post-intervention compared to control (4.0 ± 3.4 vs -0.7 ± 3.1%, respectively, P < 0.05). These results suggest that chronic AS can mitigate ST related improvements of body composition in young women.

Comparison of single- and multi-joint lower body resistance training upon strength increases in recreationally active males and females: a within-participant unilateral training study

The present study compared strength increases resulting from either single-joint (SJ) or multi-joint (MJ) lower body resistance exercise. A within-participants design was utilised. Ten recreationally active participants (males; n=5, and females; n=5) had their lower limbs randomly allocated to perform both unilateral MJ (leg press; LP) and unilateral SJ (knee extension; KE, and seated knee flexion; KF) exercises. Participants trained 2 d.week-1 for 6 weeks. Pre- and post-intervention maximal strength (1-repetition maximum; 1RM) was measured for leg press, knee extension, and seated knee flexion exercises. Statistically significant strength increases occurred for both SJ and MJ groups, with significantly greater increases in 1RM for the MJ compared to the SJ group (p < 0.001 for all exercises). This study supports the use of MJ exercise for strength increases across lower body MJ and SJ movements, suggesting a time-efficient, and simple approach to resistance training may be efficacious. This might serve to promote greater adherence in the lay population as well as serving useful for rehabilitation professionals and strength and conditioning coaches in managing resistance exercise around skill/sport specific training.

Effects of Adding Single Joint Exercises to a Resistance Training Programme in Trained Women

BACKGROUND

The present study's aim was to compare the changes in muscle performance and anthropometric measures in trained women performing RT programs composed only of MJ exercises or programmes that involve the addition of SJ exercises.

METHODS

Seventeen trained women were randomised to MJ or MJ+SJ. Both groups performed the same MJ exercises following a nonlinear periodisation model for 8 weeks. The only difference was that the MJ+SJ group also performed SJ exercises. The participants were tested for 10 repetition maximum (10 RM), flexed arm circumference, and both biceps and triceps skinfold.

RESULTS

Both groups significantly increased 10 RM load for the bench press (12.6% MJ and 9.2% MJ+SJ), triceps (15.6% MJ and 17.9% MJ+SJ), pull down (9.8% MJ and 8.3% MJ+SJ), biceps (14.0% MJ and 13.0% MJ+SJ), leg press (15.2% MJ and 12.8% MJ+SJ) and knee extension (10.2% MJ and 9.1% MJ+SJ). The decreases in triceps (-5.1% MJ and -5.3% MJ+SJ) and biceps (-6.5% MJ and -5.7% MJ+SJ) skinfolds were also significant as were the increases in arm circumference (1.47% MJ and 1.58% MJ+SJ). In all tests there was nothing significantly different between groups.

CONCLUSIONS

The use of SJ exercises as a complement to a RT programme containing MJ exercises brings no additional benefit to trained women.

Does the addition of single joint exercises to a resistance training program improve changes in performance and anthropometric measures in untrained men?

The present study compared changes in muscle performance and anthropometric measures in young men performing resistance training (RT) programs composed of only multi joint (MJ) exercises, or with the addition of single joint (SJ) exercises (MJ+SJ). Twenty untrained men were randomized to MJ or MJ+SJ groups for 8 weeks. Both groups performed the same MJ exercises. The difference was that the MJ+SJ group added SJ exercises for upper and lower limbs. Participants were tested for 10 repetitions maximum (10RM), flexed arm circumference, and biceps and triceps skinfolds. Both groups significantly increased 10RM load for the bench press (MJ 38.5%, MJ+SJ 40.1%), elbow extension (MJ 28.7%, MJ+SJ 31.9%), pull down (MJ 34.0% MJ+SJ 38.5%), elbow flexion (MJ 38.2%, MJ+SJ 45.3%), leg press (MJ 40.8%, MJ+SJ 46.8%) and knee extension (MJ 26.9%, MJ+SJ 32.9%), with no significant difference between them. The decreases in biceps (MJ -3.6%, MJ+SJ -3.9%) and triceps (MJ -3.4%, MJ+SJ -3.3%) skinfolds were significant for both groups, with no difference between them. However, the flexed arm circumference increased significantly more for MJ+SJ (5.2%), than for MJ (4.0%). The use of SJ exercises as a complement to a RT program containing MJ exercises brings no additional benefit to untrained men in terms of muscle performance and skinfold reduction, though it promoted higher increases in arm circumference.

Effect of strength training combined with antioxidant supplementation on muscular performance

This was a placebo-controlled randomized study that aimed to investigate the effects of strength training (ST) combined with antioxidant supplementation on muscle performance and thickness. Forty-two women (age, 23.8 ± 2.7 years; body mass, 58.7 ± 11.0 kg; height, 1.63 ± 0.1 m) were allocated into 3 groups: vitamins (n = 15), placebo (n = 12), or control (n = 15). The vitamins and placebo groups underwent an ST program, twice a week, for 10 weeks. The vitamins group was supplemented with vitamins C (1 g/day) and E (400 IU/day) during the ST period. Before and after training, peak torque (PT) and total work (TW) were measured on an isokinetic dynamometer, and quadriceps muscle thickness (MT) was assessed by ultrasound. Mixed-factor ANOVA was used to analyze data and showed a significant group × time interaction for PT and TW. Both the vitamins (37.2 ± 5.4 to 40.3 ± 5.6 mm) and placebo (39.7 ± 5.2 to 42.5 ± 5.6 mm) groups increased MT after the intervention (P < 0.05) with no difference between them. The vitamins (146.0 ± 29.1 to 170.1 ± 30.3 N·m) and placebo (158.9 ± 22.4 to 182.7 ± 23.2 N·m) groups increased PT after training (P < 0.05) and PT was higher in the placebo compared with the control group (P = 0.01). The vitamins (2068.3 ± 401.2 to 2295.5 ± 426.8 J) and placebo (2165.1 ± 369.5 to 2480.8 ± 241.3 J) groups increased TW after training (P < 0.05) and TW was higher in the placebo compared with the control group (P = 0.01). Thus, chronic antioxidant supplementation may attenuate peak torque and total work improvement in young women after 10 weeks of ST.

A Review of the Acute Effects and Long-Term Adaptations of Single- and Multi-Joint Exercises during Resistance Training

Resistance exercises can be considered to be multi-joint (MJ) or single-joint (SJ) in nature. Many strength coaches, trainers, and trainees believe that adding SJ exercises to a resistance training (RT) program may be required to optimize muscular size and strength. However, given that lack of time is a frequently cited barrier to exercise adoption, the time commitment resulting from these recommendations may not be convenient for many people. Therefore, it is important to find strategies that reduce the time commitment without negatively affecting results. The aim of this review was to analyze and discuss the present body of literature considering the acute responses to and long-term adaptations resulting from SJ and MJ exercise selection. Studies were deemed eligible for inclusion if they were experimental studies comparing the effects of MJ, SJ, or MJ + SJ on dependent variables; studies were excluded if they were reviews or abstracts only, if they involved clinical populations or persons with articular or musculoskeletal problems, or if the RT intervention was confounded by other factors. Taking these factors into account, a total of 23 studies were included. For the upper and lower limbs, analysis of surface electromyographic (sEMG) activation suggests that there are no differences between SJ and MJ exercises when comparing the prime movers. However, evidence is contrasting when considering the trunk extensor musculature. Only one study directly compared the effects of MJ and SJ on muscle recovery and the results suggest that SJ exercises resulted in increased muscle fatigue and soreness. Long-term studies comparing increases in muscle size and strength in the upper limbs reported no difference between SJ and MJ exercises and no additional effects when SJ exercises were included in an MJ exercise program. For the lumbar extensors, the studies reviewed tend to support the view that this muscle group may benefit from SJ exercise. People performing RT may not need to include SJ exercises in their program to obtain equivalent results in terms of muscle activation and long-term adaptations such as hypertrophy and strength. SJ exercises may only be necessary to strengthen lumbar extensors and to correct muscular imbalances.

Muscular performance and body composition changes following multi-joint versus combined multi- and single-joint exercises in aging adults

The aim of the present study was to compare muscular performance and body composition changes following low-volume resistance-training programs consisting of multi-joint (MJ) exercises (cable chest press and seated row) versus a combination of multi- and single-joint (MJ+SJ) exercises (cable chest press, seated row, biceps curl, and triceps extension). Thirty untrained healthy aging adults were randomly assigned to 3 groups: MJ (n = 11), MJ+SJ (n = 11), and control (n = 8). Twelve-repetition maximums (12-RMs) for the cable chest press and seated row, localized muscular endurance for the elbow flexors handgrip strength, and body composition were assessed before and after the 8-week training program. All comparisons were analyzed via a mixed-model analysis with repeated measures (group × time) and the Bonferroni post hoc test (p < 0.05). The MJ and MJ+SJ groups increased performance in the 12-RM cable chest press (MJ = 61.5% ± 24.6% and MJ+SJ = 71.1% ± 25.6%), 12-RM seated row (MJ = 46.4% ± 26.3% and MJ+SJ = 51.5% ± 21.0%), localized muscular endurance (MJ = 24.7% ± 16.7% and MJ+SJ = 37.0% ± 11.4%), and handgrip strength (MJ = 9.3% ± 10.4% and MJ+SJ = 16.6% ± 25.3%) after the intervention. Body composition (i.e., trunk and upper limb fat and lean mass) did not change for any groups. No significant differences were observed between the MJ versus the MJ+SJ protocols after the intervention for any variables. In conclusion, for aging adults, either MJ or MJ+SJ low-volume resistance training resulted in similar increases in 12-RM, localized muscular endurance, and handgrip strength, without changes in body composition after 8 weeks of training.

Resistance Training with Single vs. Multi-joint Exercises at Equal Total Load Volume: Effects on Body Composition, Cardiorespiratory Fitness, and Muscle Strength

The present study aimed to compare the effects of equal-volume resistance training performed with single-joint (SJ) or multi-joint exercises (MJ) on VO₂max, muscle strength and body composition in physically active males. Thirty-six participants were divided in two groups: SJ group (n = 18, 182.1 ± 5.2, 80.03 ± 2.78 kg, 23.5 ± 2.7 years) exercised with only SJ exercises (e.g., dumbbell fly, knee extension, etc.) and MJ group (n = 18, 185.3 ± 3.6 cm, 80.69 ± 2.98 kg, 25.5 ± 3.8 years) with only MJ exercises (e.g., bench press, squat, etc.). The total work volume (repetitions × sets × load) was equated between groups. Training was performed three times a week for 8 weeks. Before and after the training period, participants were tested for VO₂max, body composition, 1 RM on the bench press, knee extension and squat. Analysis of covariance (ANCOVA) was used to compare post training values between groups, using baseline values as covariates. According to the results, both groups decreased body fat and increased fat free mass with no difference between them. Whilst both groups significantly increased cardiorespiratory fitness and maximal strength, the improvements in MJ group were higher than for SJ in VO₂max (5.1 and 12.5% for SJ and MJ), bench press 1 RM (8.1 and 10.9% for SJ and MJ), knee extension 1 RM (12.4 and 18.9% for SJ and MJ) and squat 1 RM (8.3 and 13.8% for SJ and MJ). In conclusion, when total work volume was equated, RT programs involving MJ exercises appear to be more efficient for improving muscle strength and maximal oxygen consumption than programs involving SJ exercises, but no differences were found for body composition.

Nutrition, Pharmacological and Training Strategies Adopted by Six Bodybuilders: Case Report and Critical Review

The purpose of this study was to report and analyze the practices adopted by bodybuilders in light of scientific evidence and to propose evidence-based alternatives. Six (four male and two female) bodybuilders and their coaches were directly interviewed. According to the reports, the quantity of anabolic steroids used by the men was 500–750 mg/week during the bulking phase and 720–1160 mg during the cutting phase. The values for women were 400 and 740 mg, respectively. The participants also used ephedrine and hydrochlorothiazide during the cutting phase. Resistance training was designed to train each muscle once per week and all participants performed aerobic exercise in the fasted state in order to reduce body fat. During the bulking phase, bodybuilders ingested ~2.5 g of protein/kg of body weight. During the cutting phase, protein ingestion increased to ~3 g/kg and carbohydrate ingestion decreased by 10–20%. During all phases, fat ingestion corresponded to ~15% of the calories ingested. The supplements used were whey protein, chromium picolinate, omega 3 fatty acids, branched chain amino acids, poly-vitamins, glutamine and caffeine. The men also used creatine in the bulking phase. In general, the participants gained large amounts of fat-free mass during the bulking phase; however, much of that fat-free mass was lost during the cutting phase along with fat mass. Based on our analysis, we recommend an evidence-based approach by people involved in bodybuilding, with the adoption of a more balanced and less artificial diet. One important alert should be given for the combined use of anabolic steroids and stimulants, since both are independently associated with serious cardiovascular events. A special focus should be given to revisiting resistance training and avoiding fasted cardio in order to decrease the reliance on drugs and thus preserve bodybuilders’ health and integrity.

Isokinetic Dynamometry and 1RM Tests Produce Conflicting Results for Assessing Alterations in Muscle Strength

The purpose of this study was to compare strength gains in the lower limbs, assessed by one maximum repetition (1RM) and isokinetic peak torque (PT), in young men undergoing a resistance training (RT) program. Twenty-seven young men performed resistance training twice a week for 11 weeks. Training involved two exercises for the lower body, two for the upper body and one for the midsection performed with three sets of 8-12 repetitions to momentary muscle failure. Before and after the training period, participants performed the 1RM test in the 45° leg press and knee extension PT in isokinetic dynamometry. The Pearson correlation coefficient was used to assess the relationship between the changes in 1RM and PT, and the Bland-Altman test was performed to check for agreement between the strength changes of both tests. There were significant changes in 1RM and PT of 23.98% and 15.96%, respectively (p < 0.05). The changes in leg press 1RM were significantly higher than the ones in PT. The Bland-Altman analysis revealed that the tests were not equivalent. In conclusion, professionals and researchers involved in strength assessment should be aware that the results obtained by PT and 1RM are not equivalent when evaluating individual responsiveness and/or the efficacy of an intervention on muscle strength, as the results obtained show large variations and can be even conflicting.

Ultrasound imaging in women's arm flexor muscles: intra-rater reliability of muscle thickness and echo intensity

Background

Different ultrasound parameters have been frequently used to assess changes associated with training, aging, immobilization, and neuromuscular diseases. However, an exploratory reliability analysis of the echo intensity (EI) and muscle thickness (MT) of the forearm flexors is scarce, especially in women.

Objective

The purpose of the present study was to determine the intra-rater reliability of MT and EI assessed by ultrasound in young women.

Method

Ultrasonographic MT and EI were acquired in the forearm flexors of 41 young women (22±2 yrs). Reliability was calculated using intraclass correlation coefficient (ICC_2,1), standard error of measurement (SEM), coefficient of variation (CV), smallest detectable change (SDC), and Bland and Altman plot analysis.

Results

ICC values for MT and EI were 0.88 (95% CI: 0.78-0.93). The SEM and CV values were lower than 10%. Bland and Altman analysis revealed that ultrasound mean differences were 0.27 mm (Limits of Agreement - LOA 95%: - 2.6 to 3.2 mm) and -0.09 a.u. (LOA 95%: - 10.9 to 10.7 a.u.).

Conclusion

MT and EI assessed by ultrasonography in young women appear to be reliable and may be used to monitor changes in muscle mass induced by strength training when these changes exceed the precision of ultrasound.

The effects of adding single-joint exercises to a multi-joint exercise resistance training program on upper body muscle strength and size in trained men

The aim of this study was compare changes in upper body muscle strength and size in trained men performing resistance training (RT) programs involving multi-joint plus single-joint (MJ+SJ) or only multi-joint (MJ) exercises. Twenty young men with at least 2 years of experience in RT were randomized in 2 groups: MJ+SJ (n = 10; age, 27.7 ± 6.6 years) and MJ (n = 10; age, 29.4 ± 4.6 years). Both groups trained for 8 weeks following a linear periodization model. Measures of elbow flexors and extensors 1-repetition maximum (1RM), flexed arm circumference (FAC), and arm muscle circumference (AMC) were taken pre- and post-training period. Both groups significantly increased 1RM for elbow flexion (4.99% and 6.42% for MJ and MJ+SJ, respectively), extension (10.60% vs 9.79%, for MJ and MJ+SJ, respectively), FAC (1.72% vs 1.45%, for MJ and MJ+SJ, respectively), and AMC (1.33% vs 3.17% for MJ and MJ+SJ, respectively). Comparison between groups revealed no significant difference in any variable. In conclusion, 8 weeks of RT involving MJ or MJ+SJ resulted in similar alterations in muscle strength and size in trained participants. Therefore, the addition of SJ exercises to a RT program involving MJ exercises does not seem to promote additional benefits to trained men, suggesting MJ-only RT to be a time-efficient approach.

A nutrition and conditioning intervention for natural bodybuilding contest preparation: observations and suggestions

Bodybuilding is full of myths and practices that are contrary to the scientific literature, which can lead to health problems. Adopting a scientifically designed approach is very important, as it may help bodybuilders to achieve better results while preserving their health. However, I have some criticism regarding some practices adopted in the referred article as ad libitum ingestion of sugar-free cordial and flavored tea and the performance of the exercise in fasted state, as it seems to bring no benefit and have some potential problems. Some suggestion are made in order to preserve FFM, like changing training split and exercise selection; increasing carbohydrate ingestion and decreasing protein intake; changing the resistance training stimuli and reducing the volume of aerobic exercises and increase its intensity.

Strength Gains as a Result of Brief, Infrequent Resistance Exercise in Older Adults

Chronological aging is associated with a decrease in skeletal muscle mass and bone mineral density, an increase in fat mass, frequency of falls and fractures, and the likelihood of obesity, diabetes, and coronary heart disease. Resistance exercise has been shown to counter all of these effects of aging and, in turn, reduce the risk of all-cause mortality. However, variables such as volume and frequency have become contentious issues, with recent publications suggesting that similar physiological adaptations are possible with both high- and low-volume approaches. The aim of this research was to consider strength increases as a result of brief, infrequent resistance exercise. The present study offers data from 33 (14 male and 19 female) older adults (M = 55 years) who underwent brief (<15 minutes per exercise session), infrequent (2×/week), resistance exercise to a high intensity of effort (6-repetition maximum) at a controlled repetition duration (10 seconds concentric : 10 seconds eccentric) on 5 resistance machines (chest press, leg press, pull-down, seated row, and overhead press). Data is presented for training interventions of 12 weeks (male) and 19 weeks (female). Significant strength increases were identified for all exercises. With the detailed health benefits obtainable, the present study suggests that resistance exercise can be efficacious in much smaller volumes than previously considered.