The purpose of this study was to investigate the effects of 4-week (16 sessions) unilateral, maximal isometric strength training on contralateral neural adaptations. Subjects were randomised to a strength training group (TG, n = 15) or to a control group (CG, n = 11). Both legs of both groups were tested for plantar flexion maximum voluntary isometric contractions (MVCs), surface electromyogram (EMG), H-reflexes and V-waves in the soleus (SOL) and gastrocnemius medialis (GM) superimposed during MVC and normalised by the M-wave (EMG/M(SUP), H(SUP)/M(SUP), V/M(SUP), respectively), before and after the training period. For the untrained leg, the TG increased compared to the CG for MVC torque (33%, P < 0.01), SOL EMG/M(SUP) (32%, P < 0.05) and SOL V/M(SUP) (24%, P < 0.05). For the trained leg, the TG increased compared to the CG for MVC torque (40%, P < 0.01), EMG/M(SUP) (SOL: 38%, P < 0.05; GM: 60%, P < 0.05) and SOL V/M(SUP) (72%, P < 0.01). H(SUP)/M(SUP) remained unchanged for both limbs. No changes occurred in the CG. These results reinforce the concept that enhanced neural drive to the contralateral agonist muscles contributes to cross-education of strength.

Andersen, V, Fimland, MS, Mo, D-A, Iversen, VM, Vederhus, T, Rockland Hellebø, LR, Nordaune, KI, and Saeterbakken, AH. Electromyographic comparison of barbell deadlift, hex bar deadlift, and hip thrust exercises: a cross-over study. J Strength Cond Res 32(3): 587-593, 2018-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.

Lack of time is among the more commonly reported barriers for abstention from exercise programs. The aim of this review was to determine how strength training can be most effectively carried out in a time-efficient manner by critically evaluating research on acute training variables, advanced training techniques, and the need for warm-up and stretching. When programming strength training for optimum time-efficiency we recommend prioritizing bilateral, multi-joint exercises that include full dynamic movements (i.e. both eccentric and concentric muscle actions), and to perform a minimum of one leg pressing exercise (e.g. squats), one upper-body pulling exercise (e.g. pull-up) and one upper-body pushing exercise (e.g. bench press). Exercises can be performed with machines and/or free weights based on training goals, availability, and personal preferences. Weekly training volume is more important than training frequency and we recommend performing a minimum of 4 weekly sets per muscle group using a 6–15 RM loading range (15–40 repetitions can be used if training is performed to volitional failure). Advanced training techniques, such as supersets, drop sets and rest-pause training roughly halves training time compared to traditional training, while maintaining training volume. However, these methods are probably better at inducing hypertrophy than muscular strength, and more research is needed on longitudinal training effects. Finally, we advise restricting the warm-up to exercise-specific warm-ups, and only prioritize stretching if the goal of training is to increase flexibility. This review shows how acute training variables can be manipulated, and how specific training techniques can be used to optimize the training response: time ratio in regard to improvements in strength and hypertrophy. Graphic Abstract

Previous studies indicate that elastic resistance bands (ERB) can be a viable option to conventional resistance-training equipment (CRE) during single-joint resistance exercises, but their efficacy has not been established for several commonly used multiple-joint resistance exercises. Thus, we compared muscular activation levels in four popular multiple-joint exercises performed with ERB (TheraBand) vs. CRE (Olympic barbell or cable pulley machines). In a cross-over design, men and women (n = 29) performed squats, stiff-legged deadlifts, unilateral rows and lateral pulldown using both modalities. Multilevel mixed-effects linear regression analyses of main and interaction effects, and subsequent post hoc analyses were used to assess differences between the two resistance-training modalities. CRE induced higher levels of muscle activation in the prime movers during all exercises (p < .001 for all comparisons), compared to muscle activation levels induced by ERB. The magnitude of the differences was marginal in lateral pulldown and unilateral rows and for the erector spinae during stiff-legged deadlifts. In squats the quadriceps femoris activations were substantially lower for ERB. The differences between ERB and CRE were mostly observed during the parts of the contractions where the bands were relatively slack, whilst the differences were largely eliminated when the bands became elongated in the end ranges of the movements. We conclude that ERB can be a feasible training modality for lateral pulldowns, unilateral rows and to some extent stiff-legged deadlifts, but not for the squat exercise.

IntroductionChronic low back pain (LBP) is a major health problem worldwide. Multidisciplinary rehabilitation and exercise is recommended for the management of chronic LBP. However, there is a need to investigate effective exercise interventions that is available in clinics and as home-based training on a large scale. This article presents the design and rationale of the first randomized clinical trial investigating the effects of progressive resistance training with elastic bands in addition to multidisciplinary rehabilitation for patients with moderate to severe chronic LBP.Methods and analysisWe aim to enroll 100 patients with chronic LBP referred to a specialized outpatient hospital clinic in Norway. Participants will be randomized equally to either; a) 3 tion including whole-body progressive resistance training using elastic bands – followed by home-based progressive resistance training for 9 weeks, or b) 3 weeks of multidisciplinary rehabilitation including general physical exercise – followed by home-based general physical exercise for 9 weeks. Questionnaires and strength tests will be collected at baseline, weeks 3 and 12, and at 6 and 12 months. The primary outcome is between-group changes in pain-related disability at week 12 assessed by the Oswestry disability index. Secondary outcomes include pain, work ability, work status, mental health, health-related quality of life, global rating of change, general health, and muscular strength and pain-related disability up to 12 months of follow-up.DiscussionThis study will provide valuable information for clinicians working with patients with chronic LBP.Trial registrationClinicalTrials.gov, number NCT02420236.