Maximal strength training improves musculoskeletal health in amphetamine users in clinical treatment.

Amphetamine use leads to impaired skeletal health and elevated risk of osteoporosis. In the current study, we document that maximal strength training (MST), as a part of clinical treatment, works as a countermeasure, improving muscle force generating capacity, body composition, and skeletal health at sites particularly prone to osteoporotic fractures. INTRODUCTION: Amphetamine users have attenuated musculoskeletal health. MST with heavy loads, few repetitions, and emphasis on maximal mobilization in the concentric phase may increase muscle force generating capacity and skeletal health. This study investigated if MST-induced improvements in force generating capacity improved bone mineral density (BMD), trabecular bone score, and body composition in amphetamine users participating in 3-months clinical treatment. METHODS: Of 40 randomized patients, 23 completed the study: 11 in the supervised training group (TG; 8 men, 3 women, 34 ± 10 years) and 12 in the control group (CG; 9 men, 3 women, 32 ± 8 years). The TG performed hack-squat MST three times a week for 12 weeks with an intensity of ~90% of one repetition maximum (1RM). Both groups attended conventional clinical treatment. Pre-training and post-training, we assessed hack-squat 1RM and rate of force development (RFD), BMD, body composition and trabecular bone score by dual X-ray absorptiometry, and serum bone metabolism markers. RESULTS: MST induced increases in 1RM (70%) and RFD (86%), and resulted in BMD improvements at lumbar spine (3.6%) and total hip (2.4%); all improvements were different from CG (p < 0.05). Both the 1RM and RFD increases were associated with BMD improvements (lumbar spine: r = 0.73 (1RM), r = 0.60 (RFD); total hip: r = 0.61 (1RM); all p < 0.05). No differences were observed in trabecular bone score or bone metabolism markers. CONCLUSIONS: MST improved force generating capacity and skeletal health at sites prone to bone loss in amphetamine users, and advocate that MST should be implemented as a clinical strategy to restore the patients' musculoskeletal health.

Impaired skeletal health and neuromuscular function among amphetamine users in clinical treatment.

SUMMARY: This study examined musculoskeletal health in amphetamine users, compared with healthy age-matched controls. We show that amphetamine users have reduced bone mass at several skeletal sites and attenuated maximal muscle strength and force development capacity in the lower extremities. INTRODUCTION: Amphetamine use may cause poor bone quality and elevated risk of osteoporosis. The purpose of this study was to investigate whether amphetamine users exhibit reduced regional and whole body bone mineral density (BMD), altered bone metabolism, and how muscle function may relate to the patient groups' skeletal health. METHODS: We assessed hip, lumbar spine and whole body BMD, and trabecular bone score (TBS) by dual x-ray absorptiometry (DXA), and bone metabolism markers in serum and maximal strength and force development capacity in 36 amphetamine users (25 men, 30 ± 7 years; 11 women 35 ± 10 years) and in 37 healthy controls (23 men, 31 ± 9 years; 14 women, 35 ± 7 years). RESULTS: Whole body BMD was lower in amphetamine users (8% in males and 7% females, p < 0.01), as were BMD at the total hip and sub-regions of the hip (9-11% in men and 10-11 % in women, p < 0.05). Male users had 4% lower TBS (p < 0.05) and higher serum level of type 1 collagen amino-terminal propeptide (p < 0.01). This coincided with reduced lower extremity maximal strength of 30% (males, p < 0.001) and 25% (females, p < 0.05) and 27% slower muscular force development in males compared to controls (p < 0.01). CONCLUSIONS: These findings demonstrate that amphetamine users suffer from a generalized reduction in bone mass, which was associated with attenuated maximal muscle strength and force development capacity in the lower extremities.