The impact of resistance training program on the muscle strength and bone density in adolescent athletes

© 2018 Saša Bubanj et al., published by Sciendo 2018. Strength training and other modes of physical activity may be beneficial in osteoporosis prevention by maximizing bone mineral accrual in childhood and adolescence. This study focuses on the impact of the nine-month long program of resistant exercises with different level of external loads (low, middle and high) on the lower limbs explosive strength and bone tissue density in athletes adolescents aged 17 to 18 years. Sixty healthy, male athletes and non-athletes, divided into experimental (ES, sprinters, N = 45) and control sub-sample (CS, non-athletes, N = 15), were included in study. ES examinees (EG1, EG2 and EG3) were subjected to the program of resistance exercises with low level (60% of the One Repetition Maximum-1RM), middle level (70% 1RM), and high level (85% 1RM) of external loads, respectively. Bone Density values were determined by the use of a clinical sonometer.,Sahara (Hologic, Inc., MA 02154, USA). Explosive strength values of hip extensors and flexors, knee extensors and flexors, and ankle plantar and dorsiflexors were determined by the use of accelerometer.,Myotest (Sion, Switzerland) and the means of Counter Movement Jump without arms swing (CMJ) and half squat. ANOVA method for repeated measures and ANCOVA method were used to determine significant differences and resistance program effects on the lower limbs explosive strength and bone tissue density. Resistance exercise does impact the explosive strength and bone parameters in a way to increase half squat 1RM values, but decreases CMJ values, and increases speed of sound (SOS), broadband ultrasound attenuation (BUA) and bone mineral density (BMD) values in athletes-adolescents, aged 17-18 years

The effect of resistance training on bone mineral density in postmenopausal women

Osteoporosis is a systemic disease of the skeletal system characterized by low bone mineral density (BMD) and microarchitectural deterioration of bone tissue, which leads to a decrease in bone strength, greater bone fragility, and consequently to an increased risk of fractures. Osteoporosis is three times more common in women than in men, partly because women have a lower maximum bone mass, and partly because of the hormonal changes that occur at menopause. Regular exercise, and especially weight-bearing exercise which has various positive osteogenic effects, is an effective, safe and inexpensive method for preventing or delaying osteoporosis. The problem of this research is the review, systematization, analysis and comparison of the results of scientific research papers that examined the effects of resistance training on BMD in postmenopausal women. Five electronic data bases (Google Scholar, PubMed, MEDLINE, ERIC, and Research Gate) were searched, and search terms included ‘menopause’, ‘postmenopausal women’, ‘osteoporosis’, ‘bone mineral density’, ‘bone mass’, ‘resistance training’, ‘strength training’ and ‘weight-bearing training’. Inclusion criteria were controlled trials, postmenopausal women, with or without calcium supplementation. A systematic review of the available literature was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. To determine the quality of each study, the Physiotherapy Evidence Database Scale (PEDro) scale was used. A total of 16 studies met the inclusion criteria and total sample consisted of 1228 postmenopausal women. The review showed that this type of research was mostly done on a sample of less than 50 respondents; the shortest study lasted 24 weeks and contributed to the preservation of bone mineral density, and the longest had lasted for three years, during which the density improved. Calcium supplementation (600 up to 1500 mg per day) found its place in the protocol of seven studies, which gave good results in combination with exercise. Most of the studies have found a positive effect of resistance training on BMD of postmenopausal women (on the density of the lumbar spine, hips, forearms, and the whole body), but when it comes to strength training it had a positive effect only when it comes to BMD of the lumbar spine and hip, and on the total body when combined with hormone therapy. From the results of these studies we can clearly conclude that resistance training is good not only for the preservation of BMD, but that this type of training during the period longer than six months, leads to an increase in both total and regional BMD in postmenopausal women. Keywords: menopause, osteoporosis, bone density, strength trainin