Choosing breast-conserving therapy or mastectomy and subpectoral implant breast reconstruction: implications for pectoralis major function.

BACKGROUND: An increasing number of women are choosing mastectomy and subpectoral implant (SI) breast reconstruction over breast-conserving therapy (BCT). It is unclear to what extent these procedures differ in their effect on the pectoralis major (PM). The purpose of this study was to assess the impact of choosing BCT or SI breast reconstruction on PM function. METHODS: Ultrasound shear wave elastography images were acquired from the PM fiber regions and surface electromyography obtained activity from six shoulder muscles, while 14 BCT participants, 14 SI participants, and 14 age-matched controls remained at rest or generated submaximal shoulder torques. RESULTS: BCT and SI participants were significantly weaker in shoulder adduction, while BCT participants were also weaker in internal and external rotation (all p ≤ 0.003). PM function was altered following either BCT or SI. In all treatment groups, the clavicular fiber region contributed primarily to flexion, and the sternocostal primarily contributed to adduction. However, healthy participants utilized the clavicular region more during adduction and the sternocostal region more during flexion when compared to BCT or SI participants (all p ≤ 0.049). The still intact clavicular region increased its contributions to flexion torques in SI participants compared to controls (p = 0.016). Finally, BCT and SI participants compensated for changes in PM function using synergistic shoulder musculature. CONCLUSION: Both BCT and SI breast reconstruction result in significant long-term upper extremity strength deficits. Our results suggest changes to the underlying function of the PM and the adoption of unique but inadequate neuromuscular compensation strategies drive these deficits.

Effects of a 12-Week Functional Training Program on the Strength and Power of Chinese Adolescent Tennis Players.

BACKGROUND: Functional training is any type of training designed to improve a specific movement or activity for fitness or high performance sports. This study examined the effect of functional training on the strength and power of young tennis players. METHODS: 40 male tennis players were assigned to the functional training group (n = 20; age, 16.7 ± 0.4 years) or the conventional training group (n = 20; age, 16.5 ± 0.6 years). The functional training group received three 60 min sessions per week for 12 weeks, while the conventional training group participated in three sessions per week of mono-strength exercise for 12 weeks. Strength and power were measured according to the International Tennis Federation protocol at baseline, 6 weeks after the intervention, and 12 weeks after the intervention. RESULTS: Both forms of training increased (p < 0.05) push-ups, wall squat test, over medicine ball throw, and standing long jump after 6 weeks of training, and the effect improved further as the 12-week mark approached. Except for the wall squat test (left) at 6 weeks, functional training showed no advantage over conventional training. After an additional 6 weeks of training, all measures of strength and power were better (p < 0.05) in the functional training group. CONCLUSIONS: Improvements in strength and power could occur after as little as 6 weeks of functional training, and 12-week functional training could outperform conventional training in male adolescent tennis players.

Body weight influences musculoskeletal adaptation to long-term voluntary wheel running during aging in female mice.

Frailty is the hallmark of aging that can be delayed with exercise. The present studies were initiated based on the hypothesis that long-term voluntary wheel running (VWR) in female mice from 12 to 18 or 22 months of age would have beneficial effects on the musculoskeletal system. Mice were separated into high (HBW) and low (LBW) body weight based on final body weights upon termination of experiments. Bone marrow fat was significantly higher in HBW than LBW under sedentary conditions, but not with VWR. HBW was more protective for soleus size and function than LBW under sedentary conditions, however VWR increased soleus size and function regardless of body weight. VWR plus HBW was more protective against muscle loss with aging. Similar effects of VWR plus HBW were observed with the extensor digitorum longus, EDL, however, LBW with VWR was beneficial in improving EDL fatigue resistance in 18 mo mice and was more beneficial with regards to muscle production of bone protective factors. VWR plus HBW maintained bone in aged animals. In summary, HBW had a more beneficial effect on muscle and bone with aging especially in combination with exercise. These effects were independent of bone marrow fat, suggesting that intrinsic musculoskeletal adaptions were responsible for these beneficial effects.

Differential Adaptations of the Musculoskeletal System after Spinal Cord Contusion and Transection in Rats.

Spinal cord injury (SCI) causes impaired neuronal function with associated deficits in the musculoskeletal system, which can lead to permanent disability. Here, the impact of SCI on in vivo musculoskeletal adaptation was determined by studying deficits in locomotor function and analyzing changes that occur in the muscle and bone compartments within the rat hindlimb after contusion or transection SCI. Analyses of locomotor patterns, as assessed via the Basso, Beattie, and Bresnahan (BBB) rating scale, revealed that transection animals showed significant deficits, while the contusion group had moderate deficits, compared with naïve groups. Muscle myofiber cross-sectional areas (CSA) of both the soleus and tibialis anterior muscles were significantly decreased three months after contusion SCI. Such decreases in CSA were even more dramatic in the transection SCI group, suggesting a dependence on muscle activity, which is further validated by the correlation analyses between BBB score and myofiber CSA. Bone compartment analyses, however, revealed that transection animals showed the most significant deficits, while contusion animals showed no significant differences in the trabecular bone content within the proximal tibia compartment. In general, values of bone volume per total bone volume (BV/TV) were similar across the SCI groups. Significant decreases were observed, however, in the transection animals for bone mineral content, bone mineral density, and three-dimensional trabecular structure parameters (trabecular number, thickness, and spacing) compared with the naïve and contusion groups. Together, these findings suggest an altered musculoskeletal system can be correlated directly to motor dysfunctions seen after SCI.