The dorsal muscles of the lower torso and extremities have often been denoted the "posterior chain." These muscles are used to support the thoracic and lumbar spine and peripheral joints, including the hip, knee, and ankle on the dorsal aspect of the body. This study investigated the relative muscle activity of the hamstring group and selected surrounding musculature during the leg curl, good morning, glute-ham raise, and Romanian deadlift (RDL). Twelve healthy, weight-trained men performed duplicate trials of single repetitions at 85% 1-repetition maximum for each lift in random order, during which surface electromyography and joint angle data were obtained. Repeated measures analysis of variance across the 4 exercises was performed to compare the activity from the erector spinae (ES), gluteus medius (GMed), semitendinosus (ST), biceps femoris (BF), and medial gastrocnemius (MGas). Significant differences (p ≤ 0.05) were noted in eccentric muscle activity between exercise for the MGas (p < 0.027), ST (p < 0.001), BF (p < 0.001), and ES (p = 0.032), and in concentric muscle activity, for the ES (p < 0.001), BF (p = 0.010), ST (p = 0.009), MGas (p < 0.001), and the GMed (p = 0.018). Bonferroni post hoc analysis revealed significant pairwise differences during eccentric actions for the BF, ST, and MGas. Post hoc analysis also revealed significant pairwise differences during concentric actions for the ES, BF, ST, MGas, and GMed. Each of these showed effect sizes that are large or greater. The main findings of this investigation are that the ST is substantially more active than the BF among all exercises, and hamstring activity was maximized in the RDL and glute-ham raise. Therefore, athletes and coaches who seek to maximize the involvement of the hamstring musculature should consider focusing on the glute-ham raise and RDL.

Due to the broad spectrum of physical characteristics necessary for success in field sports, numerous training modalities have been used develop physical preparedness. Sports like rugby, basketball, lacrosse, and others require athletes to be not only strong and powerful but also aerobically fit and able to recover from high-intensity intermittent exercise. This provides coaches and sport scientists with a complex range of variables to consider when developing training programs. This can often lead to confusion and the misuse of training modalities, particularly in the development of aerobic and anaerobic conditioning. This review outlines the benefits and general adaptations to 3 commonly used and effective conditioning methods: high-intensity interval training, repeated-sprint training, and small-sided games. The goals and outcomes of these training methods are discussed, and practical implementations strategies for coaches and sport scientists are provided.

Background:We have recently noted an acute increase in circulating free fatty acids and glycerol, as well as resting metabolic rate, when men and women ingested the dietary supplement OxyELITE Pro™ in a single dose. We have also noted a reduction in appetite when subjects were treated with this supplement for 14 consecutive days. It is possible that such findings may favor body weight and fat loss over time. Therefore, the purpose of the present study was to determine the effects of this dietary supplement on weight loss and associated markers using an eight week intervention.Methods:Exercise-trained subjects were randomly assigned in double blind manner to ingest either the dietary supplement (n = 16; aged 22.8 ± 0.7) or a placebo (n = 16; 22.5 ± 0.5) every day for eight weeks. Body weight, body composition, skinfold thickness, serum lipids, and appetite were measured as the primary outcome variables. As measures of supplement safety, a complete blood count and comprehensive metabolic panel were performed, and resting heart rate and blood pressure were measured (pre and post intervention).Results:No interactions or main effects were noted for our primary outcome measures (P > 0.05). However, when comparing pre and post intervention values for the supplement, significant decreases were noted in appetite, body weight, body fat percentage, and skinfold thickness (P < 0.05), while increases were noted for total and HDL-C, as well as for resting heart rate (P < 0.05). No changes were noted for placebo from pre to post intervention (P > 0.05), with the exception of an increase in HDL-C (P < 0.05). Blood pressure and bloodborne safety variables were not differently impacted by supplement or placebo (P > 0.05), with the exception of monocytes, for which an interaction effect was noted (P = 0.04).Conclusion:These data indicate that the dietary supplement OxyELITE Pro™ may assist in weight and body fat loss in a sample of exercise-trained men and women. The supplement does not result in any adverse effects pertaining to resting blood pressure or bloodborne markers of safety; however a small increase in resting heart rate is observed.

Metabolic and neurological responses to 4 bouts of lower-body or upper-body resistance exercise preceded by cycle ergometry or rest were assessed. Nine resistance-trained men (26.7 ± 6.6 years) underwent bouts of (a) cycle ergometry then bench press, (b) bench press only, (c) cycle ergometry then back squat, and (d) back squat only. Cycle ergometry was performed at 75% maximum heart rate for 45 minutes. Bench press and back squat protocols required 6 sets to volitional fatigue at 80% 1RM with 2 minutes rest between sets. Significantly more repetitions were performed during set 1 for back squat without preceding aerobic exercise (12.6 ± 4.5 vs. 10.0 ± 3.5, p = 0.000) and cumulatively at set 3 (27.1 ± 10.6 vs. 23.1 ± 9.2, p = 0.014), and no differences were noted for bench press repetitions. Inclusion of cycle ergometry results in impaired back squat, but not bench press, performance likely because of a combination of local metabolic stress and various neuromuscular effects.

Resistance training is an effective way to achieve optimal gains in muscle mass and strength and has also been well documented in attenuating various forms of skeletal muscle wasting (e.g., sarcopenia). Moreover, it has been demonstrated that with appropriate training, older adults can reverse strength and muscle mass deficits to younger levels. To attain maximal benefits, careful manipulation of training variables, such as intensity, volume and frequency, is required. Although training intensity and training volume have been extensively studied, there is only scarce information available on the adaptive responses to frequency manipulations in older populations. Thus, we compared the effects of shortterm (8 weeks) resistance training programs performed either 2 days/week (n ¼ 15, 7 males, 8 females) or 3 days/week (n ¼ 14, 4 males, 10 females) on muscle mass, upper-and lower-body strength and functional abilities in individuals aged > 60 years. Chest press strength increased in both the 2 times/week and 3 times/week groups over the 8-week training period by 20.84% and 20.18%, respectively. Lower-body (leg press) strength also showed improvements in both groups: 22.34% in the 2 times/week group and 28.12% in the 3 times/week group. There was a slight, but nevertheless significant gain of lean body mass from pre-to post-training (2.4% and 1.9% for the 2 days and 3 days groups, respectively). However, functional performance remained unchanged in the groups. We found that short-term resistance training 2 times/week or 3 times/week elicited comparable muscle strength and lean body mass adaptations in older adults.