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Purpose: The Nordic hamstring exercise (NHE) has been shown to considerably reduce hamstring injuries among soccer players. However, as the load in the NHE is the person's own bodyweight, it is a very heavy exercise and difficult to individualize. The flywheel inertial leg curl (FLC) could be an alternative since the eccentric overload is based on the amount of work produced in the concentric movement. Therefore, the primary aim of this study was to compare the activation in the hamstrings at long muscle lengths in the NHE and the FLC in amateur soccer players., Methods: Fifteen male amateur soccer players performed 5 repetitions in each exercise in a randomized and counterbalanced order. The concentric and eccentric movements were divided into lower and upper phases. Surface EMG was measured distally, proximally, and in the middle, at both muscles., Results: In the lower phase in the eccentric movement, there were no significant differences between the 2 exercises (P = .101-.826). In the lower concentric movement, the FLC led to higher activation in all parts of both the biceps femoris (31%-52%, P < .001) and the semitendinosus (20%-35%, P = .001-.023)., Conclusion: Both exercises activated the hamstrings similarly at long muscle lengths during eccentric contractions (Nordic hamstring, nonsignificantly higher). However, when performing concentric contractions, the FLC induced higher activations. Therefore, the FLC could be a useful alternative to the NHE and particularly suitable for weaker athletes before progressing to NHE.

The aim of the study was to compare the EMG amplitude in bench press (stable loads) to bench press using loads moving in anteroposterior and mediolateral directions. Seventeen resistance-trained men, with 9.4±4.7 years of resistance training experience were recruited. After a familiarization session assessing 1 repetition maximum (RM) in the bench press, participants performed: 1) bench press with traditional stable loading 2) bench press with loads (2x5kg) attached as pendulums swinging forward/backwards and 3) left/right in randomized order. The total load was 70% of the 1RM load. Electromyography was measured in the pectoralis major, anterior- and posterior deltoid, biceps brachii, triceps brachii and external obliques. Using stable loads, the pectoralis major demonstrated lower EMG amplitude compared to the two unstable conditions. In the external obliques, the stable conditions demonstrated lower EMG amplitude than the swing in the mediolateral direction, but not the anteroposterior direction. There were no differences between two swinging loads or the three conditions for the triceps brachii, biceps brachii, anterior deltoid or posterior deltoid. In conclusion, swinging in bench press resulted in similar EMG amplitude in the shoulder- and arm muscles, but greater pectoralis and external oblique (only mediolateral swing) activity compared to bench press., Competing Interests: The authors have declared that no competing interests exist.

Integrated exercises that mimic daily tasks are generally preferred for improving performance and the later stages of rehabilitation, but it is unknown whether integrated core exercises are better than isolated core exercises at improving muscle activation for hypertrophy. The aim of the study was to compare the electromyographic (EMG) activity in rectus abdominis, oblique externus, and erector spinae while performing three conditions of integrated core exercises (lunges) with three isolated core exercises (prone bridge, side bridge and back extension). The three conditions of lunges were: on a stable surface, unstable surface and with external resistance to the trunk using an elastic band. The external resistance was measured with a force cell and peaked at 75N. After one familiarization session, all exercises were performed in one experimental session in randomized order. The isolated core exercises were performed in 20 seconds and the time performing the five repetitions with lunges was matched (20 seconds). Significantly greater peak normalized EMG activity were observed in the isolated core exercises compared to the three integrated core exercises (P<0.001) with two exceptions. For the oblique externus, the isolated core exercise was only greater than the stable lunge. Lunges with elastic bands only demonstrated greater peak erector spinae activation compared the other lunge conditions. Comparing the mean EMG activity between the isolated and three integrated exercises, greater muscle activations were observed performing the isolated exercises (P<0.001). Unstable lunges did not increase the peak or mean core muscle activations. In conclusion, mean and peak EMG activity performing the isolated exercises were in general greater than the three condition of lunges. Based on these results, we recommend using isolated core exercises when the primary goal is to improve muscle activation and elicit hypertrophy, but integrated exercises once adequate initial hypertrophy is achieved., Competing Interests: The authors have declared that no competing interests exist.

The purpose of the study was to compare kinematic muscle activation when performing 6 repetition maximum (6RM) squats using constant (free weights) or variable resistance (free weights + elastic bands). Twenty recreationally trained women were recruited with 4.6 ± 2.1 years of resistance training experience and a relative strength (6RM/body mass) of 1.1. After a familiarization session identifying the 6RM loads, the participants performed 6RM squats using constant and variable resistance in a randomized order. The total resistance in the variable resistance group was similar to the constant resistance in the presticking region (98%), but greater in the sticking region (105%) and the poststicking region (113%). In addition, the presticking barbell velocity was 21.0% greater using variable than constant resistance, but 22.8% lower in the poststicking region. No significant differences in muscle electromyographic activity, time occurrence, and vertical displacement between the squat modalities were observed, except for higher barbell displacement poststicking using variable resistance. It was concluded that, due to differences in total resistance in the different regions performing variable compared with constant resistance, greater barbell velocity was observed in the presticking region and lower resistance was observed in the poststicking region. However, the extra resistance in the sticking and poststicking regions during the variable resistance modality did not cause increased muscle activity. When performing squats with heavy resistance, the authors recommend using variable resistance, but we suggest increasing the percentage resistance from the elastic bands or using chains.

Copyright of Movement & Sport Sciences / Science & Motricité is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Movement & Sport Sciences / Science & Motricité is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to assess the short- and long-term effects of resistance training (RT) with different stability requirements. Fifty-nine men underwent a 3-week familiarization period followed by a 7-week training period. During familiarization, all participants trained four sessions of squats with a Smith machine, free weights and free weights standing on a wobble board. After week-3, participants were randomized into a low (Smith machine), medium (Free-weight) or high (Wobble board) stability RT program, and Control group. All participants were tested pre-, after week-3 and post-intervention. Ten repetition maximum (10RM), rate of force development (RFD), electromyography (EMG) and maximum voluntary isometric contraction (MVIC) were tested in all three squat conditions in addition to countermovement jump (CMJ) on stable and unstable surfaces, and muscle thickness. After familiarization, greater 10RM loads (21.8–27.3%), MVIC (7.4–13.5%), RFD (29.7–43.8%) and CMJ (4.9–8.5%) were observed in all conditions. Between week 3 and 10, the Free-weight and Wobble board groups similarly improved 10RM in all conditions. Smith machine group demonstrated greater improvement in the trained exercise than the medium and high stability exercises. All training groups showed similar improvement in muscle thickness, RFD and MVIC. There was no CMJ improvement on the stable surface, but the Wobble board group demonstrated significantly greater improvement on the unstable surface. In conclusion, low, medium or high stability RT resulted in similar improvements in trained and non-trained testing conditions except for greater CMJ on the unstable surface in the Wobble group. Greater 10RM strength in trained than non-trained exercise was only observed in low stability group. Familiarization was associated with substantial improvements in 10RM and CMJ, with greater improvement associated with higher stability requirements. These findings suggest that high stability can increase strength, muscle thickness and explosive measurements similar to training with lower stability. [ABSTRACT FROM AUTHOR]

Variable, external resistance is proposed to increasingly augment the muscular stress throughout a dynamic movement. However, it is uncertain how different levels of variable resistance affect the activation in the deadlift. The aim of the study was to compare the electromyographic activity of the gluteus maximus, biceps femoris, semitendinosus, vastus lateralis and erector spinae muscles during the barbell deadlift with free weights (FW) alone, with two (FW-2EB), and four elastic bands (FW-4EB) to deload some of the constant external resistance. Fifteen resistance-trained men participated in a cross-over design where resistance loadings were matched using two-repetition maximum loadings in the three different conditions. For the whole movement, both repetitions were analyzed. For the phase-specific analysis, the last repetition was divided into six parts, i.e. the lower, middle and upper phase in both the ascending and descending phase of the movement. The mean deloading contributions from FW-2EB and FW-4EB were 21% and 41%, respectively. In FW-4EB, the erector spinae was activated more in the whole movement (8%, ES = 0.31, p = 0.002) compared to FW-2EB. There was also a tendency towards higher activation in FW-4EB versus FW for the whole movement (5%, ES = 0.18, p = 0.072). There were no significant differences between the conditions in any of the other phases or muscles (p = 0.106–0.926). In summary, a high contribution from variable, external resistance seems to activate the back extensors more than a low contribution. [ABSTRACT FROM AUTHOR]

The aim of the study was to compare the muscle activation level of the gluteus maximus, biceps femoris, and erector spinae in the hip thrust, barbell deadlift, and hex bar deadlift; each of which are compound resisted hip extension exercises. After 2 familiarization sessions, 13 resistance-trained men performed a 1 repetition maximum in all 3 exercises in 1 session, in randomized and counterbalanced order. The whole ascending movement (concentric phase), as well as its lower and upper parts (whole movement divided in 2), were analyzed. The hip thrust induced greater activation of the gluteus maximus compared with the hex bar deadlift in the whole (16%, p = 0.025) and the upper part (26%, p = 0.015) of the movement. For the whole movement, the biceps femoris was more activated during barbell deadlift compared with both the hex bar deadlift (28%, p < 0.001) and hip thrust (20%, p = 0.005). In the lower part of the movement, the biceps femoris activation was, respectively, 48% and 26% higher for the barbell deadlift (p < 0.001) and hex bar deadlift (p = 0.049) compared with hip thrust. Biceps femoris activation in the upper part of the movement was 39% higher for the barbell deadlift compared with the hex bar deadlift (p = 0.001) and 34% higher for the hip thrust compared with the hex bar deadlift (p = 0.002). No differences were displayed for the erector spinae activation (p = 0.312-0.859). In conclusion, the barbell deadlift was clearly superior in activating the biceps femoris compared with the hex bar deadlift and hip thrust, whereas the hip thrust provided the highest gluteus maximus activation. [ABSTRACT FROM AUTHOR]

Andersen, V, Fimland, MS, Kolnes, MK, and Saeterbakken, AH. Elastic bands in combination with free weights in strength training: neuromuscular effects. J Strength Cond Res 29(10): 2932-2940, 2015—This study compared the effects of a variable vs. a constant lower limb resistance training program on muscle strength, muscle activation, and ballistic muscle performance at different knee angles. Thirty-two females were randomized to a constant resistance training free-weight group (FWG) or a variable resistance training group using free weights in combination with elastic bands (EBG). Two variations of the squat exercise (back squat and split) were performed 2 days per week for 10 weeks. Knee extensor maximal voluntary isometric contraction (MVC) and countermovement jump were assessed at knee angles of 60, 90, and 1208 before and after the intervention. During the MVCs, muscle activation of the superficial knee extensor muscles was measured using surface electromyography. The FWG increased their MVCs at 60 and 90° (24 and 15%, respectively), whereas the EBG only increased significantly at 608 (15%). The FWG increased their jump height significantly at all angles (12-16%), whereas the EBG only improved significantly at 60 and 90° (15 and 10%, respectively). Both groups improved their 6-repetition maximum free-weight squat performance (EBG: 25% and FWG: 23%). There were no significant changes in muscle activation. In conclusion, constant and variable resistance training provided similar increases in dynamic and isometric strength, and ballistic muscle performance, albeit most consistently for the group training only with free weights. [ABSTRACT FROM AUTHOR]

The article discusses research which compared six repetition maximum load and electromyographic activity in the lat pull-down using 3 different pronated grip widths and evaluated the effects grip width had on muscle strength and activation in the lat pull-down. Researchers evaluated 15 men who performed lat pull-downs with three grips. They found that a medium grip may have some minor advantages over small and wide grips but that similar muscle activation was seen with all grips.