The delivery of efficient nonpharmacological treatment to prevent the loss of muscle mass in older adults is a major challenge, and information on the combined effects of training and diet is particularly important. Here we aimed to evaluate the effects of 24 wk of resistance training combined with a healthy dietary approach (n-6/n-3 ratio < 2) in a population of healthy and physically active older women (65-70 years). The three-armed randomized controlled trial included a resistance training + healthy diet group (RT-HD), a resistance training group (RT), and controls (CON). All subjects included in the study were physically active and had low levels of serum inflammatory markers. In accordance with the dietary goals, the n-6/n-3 ratio dietary intake significantly decreased only in RT-HD by 42%. An increase in 1 repetition maximum in leg extension occurred in RT (+20.4%) and RT-HD (+20.8%), but not in CON. Interestingly, leg lean mass significantly increased only in RT-HD (+1.8%). While there were no changes in serum C-reactive protein and IL-6 levels, a significant decrease in serum level of the pro-inflammatory precursor arachidonic acid (-5.3 ± 9.4%) together with an increase in serum n-3 docosahexaenoic acid (+8.3%) occurred only in RT-HD. Altogether, this study demonstrates that the effects of resistance training on muscle mass in healthy older adults can be optimized by the adoption of a healthy diet.
Background/Aims: Mechanisms underlying the relationship between systemic inflammation and age-related decline in muscle mass are poorly defined. The purpose of this work was to investigate the relationship between the systemic inflammatory marker CRP and muscle mass in elderly and to identify mechanisms by which CRP mediates its effects on skeletal muscle, in-vitro. Methods: Muscle mass and serum CRP level were determined in a cohort of 118 older women (67±1.7 years). Human muscle cells were differentiated into myotubes and were exposed to CRP. The size of myotubes was determined after immunofluorescent staining using troponin. Muscle protein synthesis was assessed using stable isotope tracers and key signalling pathways controlling protein synthesis were determined using western-blotting. Results: We observed an inverse relationship between circulating CRP level and muscle mass (β= -0.646 (95% CI: -0.888, -0.405) p<0.05) and demonstrated a reduction (p < 0.05) in the size of human myotubes exposed to CRP for 72 h. We next showed that this morphological change was accompanied by a CRP-mediated reduction (p < 0.05) in muscle protein fractional synthetic rate of human myotubes exposed to CRP for 24 h. We also identified a CRPmediated increased phosphorylation (p<0.05) of regulators of cellular energy stress including AMPK and downstream targets, raptor and ACC-β, together with decreased phosphorylation of Akt and rpS6, which are important factors controlling protein synthesis. Conclusion: This work established for the first time mechanistic links by which chronic elevation of CRP can contribute to age-related decline in muscle function.
ObjectivesTo compare collagenase injections and surgery (fasciectomy) for Dupuytren's contracture (DC) regarding actual total direct treatment costs and short-term outcomes.DesignRetrospective cohort study.SettingOrthopaedic department of a regional hospital in Sweden.ParticipantsPatients aged 65 years or older with previously untreated DC of 30° or greater in the metacarpophalangeal (MCP) and/or proximal interphalangeal (PIP) joints of the small, ring or middle finger. The collagenase group comprised 16 consecutive patients treated during the first 6 months following the introduction of collagenase as treatment for DC at the study centre. The controls were 16 patients randomly selected among those operated on with fasciectomy at the same centre during the preceding 3 years.InterventionsTreatment with collagenase was given during two standard outpatient clinic visits (injection of 0.9 mg, distributed at multiple sites in a palpable cord, and next-day finger extension under local anaesthesia) followed by night-time splinting. Fasciectomy was carried out in the operating room (day surgery) under general or regional anaesthesia using standard technique, followed by therapy and splinting.Primary and secondary outcome measuresActual total direct costs (salaries of all medical personnel involved in care, medications, materials and other relevant costs), and total MCP and PIP extension deficit (degrees) measured by hand therapists at 6–12 weeks after the treatment.ResultsCollagenase injection required fewer hospital outpatient visits to a therapist and nurse than fasciectomy. Total treatment cost for collagenase injection was US$1418.04 and for fasciectomy US$2102.56. The post-treatment median (IQR) total extension deficit was 10 (0–30) for the collagenase group and 10 (0–34) for the fasciectomy group.ConclusionsTreatment of DC with one collagenase injection costs 33% less than fasciectomy with equivalent efficacy at 6 weeks regarding reduction in contracture.
We aimed to examine cellular and molecular changes in skeletal muscle of recreationally active older women in response to 24 weeks of combined resistance training and N-3 PUFA-rich healthy diet. Sixty-three women (65-70 years) were randomized into resistance training and healthy diet rich in N-3PUFAs (RT-HD), resistance training only (RT) and controls (CON). Fiber type-specific morphological characteristics and gene expression of inflammatory biomarkers and regulators of muscle mass were analyzed in m. vastus lateralis biopsies obtained before the intervention and 4 days after the last training session. Gene expression of the proinflammatory cytokine IL-1β was downregulated (p < .05) and that of the regulator of cellular growth mTOR (p < 0.05) was upregulated in skeletal muscle of RT-HD only. There was also a significant hypertrophy of fast type IIA muscle fibers in RT-HD only (+23%, p < .05). In conclusion, resistance training combined to an N-3 PUFA-rich healthy diet but not alone triggers local anti-inflammatory and growth responses, favoring skeletal muscle hypertrophy in already recreationally active older women.
The effects of 24 wk of resistance training combined with a healthy diet on lower limb explosive strength capacity were investigated in a population of healthy elderly women. Participants ( = 63; 67.5 ± 0.4 yr) were randomized into three groups; resistance training (RT), resistance training and healthy diet (RT-HD), and control (CON). Progressive resistance training was performed at a load of 75-85% one-repetition maximum. A major adjustment in the healthy dietary approach was an n-6/n-3 polyunsaturated fatty acid (PUFA) ratio below 2. Lower limb maximal strength, explosive force capacity during dynamic and isometric movements, whole body lean mass, and physical function were assessed. Whole body lean mass significantly increased by 1.5 ± 0.5% in RT-HD only. Isometric strength performance during knee extension as well as the performance in the five sit-to-stand and single-leg-stance tests increased similarly in RT and RT-HD. Improvements in dynamic peak power and time to reach peak power (i.e shorter time) during knee extension occurred in both RT (+15.7 ± 2.6 and -11.0 ± 3.8%, respectively) and RT-HD (+24.6 ± 2.6 and -20.3 ± 2.7%, respectively); however, changes were significantly larger in RT-HD. Similarly, changes in peak force and rate of force development during squat jump were higher in RT-HD (+58.5 ± 8.4 and +185.4 ± 32.9%, respectively) compared with RT (+35.7 ± 6.9 and +105.4 ± 22.4%, respectively). In conclusion, a healthy diet rich in n-3 PUFA can optimize the effects of resistance training on dynamic explosive strength capacity during isolated lower limb movements and multijoint exercises in healthy elderly women. Age-related decline in lower limb explosive strength leads to impaired ability to perform daily living tasks. The present randomized controlled trial demonstrates that a healthy diet rich in n-3 polyunsaturated fatty acid (n-3 PUFA) enhances resistance training-induced gains in dynamic explosive strength capacity during isolated lower limb movements and multijoint exercises in healthy elderly women. This supports the use of strategies combining resistance training and dietary changes to mitigate the decline in explosive strength capacity in older adults.
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