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Protein supplementation in combination with resistance training may increase muscle mass and muscle strength in elderly subjects. The objective of this study was to assess the influence of post-exercise protein supplementation with collagen peptides v. placebo on muscle mass and muscle function following resistance training in elderly subjects with sarcopenia. A total of fifty-three male subjects (72·2 (sd 4·68) years) with sarcopenia (class I or II) completed this randomised double-blind placebo-controlled study. All the participants underwent a 12-week guided resistance training programme (three sessions per week) and were supplemented with either collagen peptides (treatment group (TG)) (15 g/d) or silica as placebo (placebo group (PG)). Fat-free mass (FFM), fat mass (FM) and bone mass (BM) were measured before and after the intervention using dual-energy X-ray absorptiometry. Isokinetic quadriceps strength (IQS) of the right leg was determined and sensory motor control (SMC) was investigated by a standardised one-leg stabilisation test. Following the training programme, all the subjects showed significantly higher (P<0·01) levels for FFM, BM, IQS and SMC with significantly lower (P<0·01) levels for FM. The effect was significantly more pronounced in subjects receiving collagen peptides: FFM (TG +4·2 (sd 2·31) kg/PG +2·9 (sd 1·84) kg; P<0·05); IQS (TG +16·5 (sd 12·9) Nm/PG +7·3 (sd 13·2) Nm; P<0·05); and FM (TG –5·4 (sd 3·17) kg/PG –3·5 (sd 2·16) kg; P<0·05). Our data demonstrate that compared with placebo, collagen peptide supplementation in combination with resistance training further improved body composition by increasing FFM, muscle strength and the loss in FM.

Progressive resistance exercise training (PRT) is the most effective known intervention for combating aging skeletal muscle atrophy. However, the hypertrophic response to PRT is variable, and this may be due to muscle inflammation susceptibility. Metformin reduces inflammation, so we hypothesized that metformin would augment the muscle response to PRT in healthy women and men aged 65 and older. In a randomized, double‐blind trial, participants received 1,700 mg/day metformin (N = 46) or placebo (N = 48) throughout the study, and all subjects performed 14 weeks of supervised PRT. Although responses to PRT varied, placebo gained more lean body mass (p = .003) and thigh muscle mass (p < .001) than metformin. CT scan showed that increases in thigh muscle area (p = .005) and density (p = .020) were greater in placebo versus metformin. There was a trend for blunted strength gains in metformin that did not reach statistical significance. Analyses of vastus lateralis muscle biopsies showed that metformin did not affect fiber hypertrophy, or increases in satellite cell or macrophage abundance with PRT. However, placebo had decreased type I fiber percentage while metformin did not (p = .007). Metformin led to an increase in AMPK signaling, and a trend for blunted increases in mTORC1 signaling in response to PRT. These results underscore the benefits of PRT in older adults, but metformin negatively impacts the hypertrophic response to resistance training in healthy older individuals. ClinicalTrials.gov Identifier: NCT02308228. Because metformin reduces inflammation, we hypothesized that it would augment the muscle response to progressive resistance exercise training (PRT) in healthy older participants. Following 14 weeks of PRT, metformin blunted gains in lean mass, thigh muscle mass, and thigh muscle density compared to placebo. Metformin did not affect increases in muscle macrophage abundance. However, metformin increased AMPK signaling, leading to a reduced mean increase in mTOR signaling.

Context:Findings of studies of testosterone’s effects on muscle strength and physical function in older men have been inconsistent; its effects on muscle power and fatigability have not been studied.Objective:To determine the effects of testosterone administration for 3 years in older men on muscle strength, power, fatigability, and physical function.Design, Setting, and Participants:This was a double-blind, placebo-controlled, randomized trial of healthy men ≥60 years old with total testosterone levels of 100 to 400 ng/dL or free testosterone levels <50 pg/mL.Interventions:Random assignment to 7.5 g of 1% testosterone or placebo gel daily for 3 years.Outcome Measures:Loaded and unloaded stair-climbing power, muscle strength, power, and fatigability in leg press and chest press exercises, and lean mass at baseline, 6, 18, and 36 months.Results:The groups were similar at baseline. Testosterone administration for 3 years was associated with significantly greater performance in unloaded and loaded stair-climbing power than placebo (mean estimated between-group difference, 10.7 W [95% confidence interval (CI), −4.0 to 25.5], P = 0.026; and 22.4 W [95% CI, 4.6 to 40.3], P = 0.027), respectively. Changes in chest-press strength (estimated mean difference, 16.3 N; 95% CI, 5.5 to 27.1; P < 0.001) and power (mean difference 22.5 W; 95% CI, 7.5 to 37.5; P < 0.001), and leg-press power were significantly greater in men randomized to testosterone than in those randomized to placebo. Lean body mass significantly increased more in the testosterone group.Conclusion:Compared with placebo, testosterone replacement in older men for 3 years was associated with modest but significantly greater improvements in stair-climbing power, muscle mass, and power. Clinical meaningfulness of these treatment effects and their impact on disability in older adults with functional limitations remains to be studied.Testosterone replacement in older men for 3 years was associated with modest but significantly greater improvements in muscle power and physical function compared with placebo.

•Older patients undergoing stroke rehabilitation are at high risk for sarcopenia and malnutrition.•We examined the efficacy and safety of a leucine-enriched amino acid supplement in post-stroke older patients with sarcopenia.•To our knowledge, this is the first interventional trial including nutritional supplementation in such patients.•Study outcomes included muscle mass, muscle strength, and physical function.•A leucin-enriched nutritional supplement increased muscle mass, strength, and physical function in this population. The aim of this study was to investigate the effects of a leucine-enriched amino acid supplement on muscle mass, muscle strength, and physical function in post-stroke patients with sarcopenia. We conducted an eight-wk, two-parallel group intervention, randomized controlled, blinded outcome assessment among 44 post-stroke older patients with sarcopenia. Sarcopenia was defined as a loss of skeletal muscle mass and decreased muscle strength according to the Asian Working Group for Sarcopenia criteria. The intervention group (n = 21) received a leucine-enriched amino acid supplement; the control group (n = 23) did not. Both groups performed low-intensity resistance training in addition to a post-stroke rehabilitation program. A primary outcome of physical function by using the motor domain of Functional Independence Measure (FIM), and secondary outcomes of appendicular muscle mass (skeletal muscle mass index [SMI]) measured via bioelectrical impedance analysis and muscle strength as handgrip strength were measured at baseline and at the end of the intervention. The FIM score increased significantly in both groups over time (P < 0.01), with significantly greater improvement in the intervention group than in the control group (P < 0.045). Handgrip strength also increased significantly over time (P <0.05), with significantly greater improvement in the intervention group (P < 0.01). The SMI increased significantly in the intervention group but not in the control group over time, with significantly greater improvement in the intervention group (median estimated difference, 0.50 kg/m2; 95% confidence interval, 0.01–2.11). We demonstrated that an eight-wk intervention consisting of a leucine-enriched amino acid supplementation and low-intensity resistance training increased muscle mass, strength, and physical function in post-stroke patients with sarcopenia.

Background: This study evaluates whether the initial amount of dietary protein intake could influence the combined effect of high-intensity interval training (HIIT) and citrulline (CIT), or HIIT alone, on body composition, muscle strength, and functional capacities in obese older adults. Methods: Seventy-three sedentary obese older men and women who completed a 12-week elliptical HIIT program with double-blinded randomized supplementation of CIT or placebo (PLA) were divided into four groups according to their initial protein intake (CIT–PROT+: n = 21; CIT–PROT−: n = 19; PLA–PROT+: n = 19; PLA–PROT−: n = 14). Body composition (fat and fat-free masses), handgrip (HSr) strength, knee extensor (KESr) strength, muscle power, and functional capacities were measured pre-intervention and post-intervention. Results: Following the intervention, the four groups improved significantly regarding all the parameters measured. For the same initial amount of protein intake, the CIT–PROT− group decreased more gynoid fat mass (p = 0.04) than the PLA–PROT− group. The CIT–PROT+ group increased more KESr (p = 0.04) than the PLA–PROT+ group. In addition, the CIT–PROT− group decreased more gynoid FM (p = 0.02) and improved more leg FFM (p = 0.02) and HSr (p = 0.02) than the CIT–PROT+ group. Conclusion: HIIT combined with CIT induced greater positive changes than in the PLA groups. The combination seems more beneficial in participants consuming less than 1 g/kg/d of protein, since greater improvements on body composition and muscle strength were observed.

The essential amino acid leucine (LEU) plays a crucial role in promoting resistance-training adaptations. Dileucine (DILEU), a LEU-LEU dipeptide, increases MPS rates, however its impact on resistance training outcomes remains unexplored. This study assessed the effects of DILEU supplementation on resistance training adaptations. Using a randomized, double-blind, placebo-controlled approach, 34 resistance-trained males (age: 28.3 ± 5.9 years) consumed 2 grams of either DILEU monohydrate (RAMPS™, Ingenious Ingredients, L.P.), LEU, or placebo (PLA) while following a 4-day per week resistance training program for 10 weeks. Changes in body composition, 1-repetition maximum (1RM) and repetitions to failure (RTF) for leg press (LP) and bench press (BP), anaerobic capacity, countermovement jump (CMJ), and maximal voluntary contraction (MVC) were assessed after 0 and 10 weeks. Significant main effects for time (p < 0.001) were realized for LP and BP 1RM and RTF. A significant group × time interaction was identified for changes in LP 1RM (p = 0.02) and LP RTF (p = 0.03). Greater increases in LP 1RM were observed in DILEU compared to PLA (p = 0.02; 95% CI: 5.8, 73.2 kg), and greater increases in LP RTF in DILEU compared to LEU (p = 0.04; 95% CI: 0.58, 20.3 reps). No significant differences were found in other measures. DILEU supplementation at 2 grams daily enhanced lower body strength and muscular endurance in resistance-trained males more effectively than LEU or PLA. These findings suggest DILEU as a potentially effective supplement for improving adaptations to resistance training. NCT06121869 retrospectively registered.

Background and ObjectivesTotal knee arthroplasty (TKA) is often associated with severe pain. Different regional anesthetic techniques exist, all with varying degrees of motor blockade. We hypothesized that pain relief provided by the adductor canal block (ACB) could increase functional muscle strength.MethodsWe included 50 TKA patients with severe movement-related pain; defined as having visual analog scale pain score of greater than 60 mm during active flexion of the knee. The ACB group received an ACB with ropivacaine 0.2% 30 mL and a femoral nerve block (FNB) with 30 mL saline. The FNB group received an ACB with 30 mL saline and an FNB with ropivacaine 0.2% 30 mL. We compared the effect of the ACB versus FNB on maximum voluntary isometric contraction of the quadriceps muscle relative to a postoperative baseline value. Secondary end points were differences between groups in ability to ambulate and changes in pain scores (Clinicaltrials.gov identifier NCT01922596).ResultsAfter block, the quadriceps maximum voluntary isometric contraction increased to 193% (95% confidence interval [CI], 143–288) of the baseline value in the ACB group and decreased to 16% (95% CI, 3–33) in the FNB group with an estimated difference of 178% (95% CI, 136–226), P < 0.0001. Pain scores were similar between groups. Before block, 2 of 25 patients in each group were unable to perform the Timed-Up-and-Go test; after block, this number increased to 7 of 25 in the FNB group and decreased to 0 of 25 in the ACB group.ConclusionAdductor canal block provides a clinically relevant and statistically significant increase in quadriceps muscle strength for patients in severe pain after TKA.

Background and ObjectivesAdductor canal block (ACB) has been suggested as an analgesic alternative to femoral nerve block (FNB) for procedures on the knee, but its effect on quadriceps motor function is unclear. We performed a randomized, blinded study to compare quadriceps strength following adductor canal versus FNB in volunteers. Our hypothesis was that quadriceps strength would be preserved following ACB, but not FNB. Secondary outcomes included relative preservation of hip adduction and degree of balance impairment.MethodsThe ACB was performed in one leg and the FNB in the contralateral leg in 16 volunteers using a randomized block sequence. For all blocks, 15 mL of 3% chloroprocaine was injected under ultrasonographic guidance. Maximal voluntary isometric contraction of knee extension and hip adduction was measured at baseline and at 30 and 60 minutes after block. After 60-minute assessments were complete, the second block was placed. A test of balance (Berg Balance Scale) was performed 30 minutes after the first block only.ResultsQuadriceps strength and balance scores were similar to baseline following ACB. Following FNB, there was a significant reduction in quadriceps strength (95.1% ± 17.1% vs 11.1% ± 14.0%; P < 0.0001) and balance scores (56 ± 0 vs 37 ± 17.2; P = 0.02) compared with baseline. There was no difference in hip adductor strength (97.0% ± 10.8% vs 91.8% ± 9.6%; P = 0.17).ConclusionsCompared with FNB, ACB results in significant quadriceps motor sparing and significantly preserved balance.

Background and aimsAnterior quadratus lumborum block is a truncal block, applied in close proximity to the lumbar plexus, potentially causing lower limb weakness. This trial aimed to evaluate whether a unilateral anterior quadratus lumborum block caused quadriceps muscle weakness compared with placebo.MethodsIn this randomized, non-inferiority, triple-blind trial, 20 healthy volunteers received an active unilateral anterior quadratus lumborum block with 30 mL ropivacaine 0.75% and a placebo block on the contralateral side. Primary outcome was change in maximal quadriceps muscle strength from baseline to 60 min postblock compared with placebo. Secondary outcomes were change in single-leg 6 m timed hop test, change in Timed-Up and Go test, change in mean arterial pressure from baseline to 30 min postblock and dermatomal affection.ResultsThere was no statistically significant difference in changes in maximal quadriceps muscle strength between active and placebo block; 15.88 N (95% CI −12.19 to +43.94), pnon-inf=0.003, indicating non-inferiority. Timed-Up and Go test was performed significantly faster 60 min postblock; −0.23 s (95% CI −0.38 to −0.08, p=0.005). Mean change in mean arterial pressure from baseline to 30 min postblock was 4.25 mm Hg (95% CI 0.24 to 8.26, p=0.04). Dermatome testing revealed an affection primarily of the lower abdomen (Th10-L1) with the active block.ConclusionIn this randomized controlled trial including healthy volunteers a unilateral anterior quadratus lumborum block does not cause statistical or clinical significant motor block of the quadriceps muscle compared with placebo. When administered correctly, the block can be used for procedures where early postoperative mobilization is essential.Trial registration number NCT05023343.

Cannabidiol supplements (CBD) are increasingly consumed by athletes to improve regeneration. However, the evidence for the pro-regenerative effects of CBD in sports is quite limited. Therefore, our aim was to investigate the effects of a single CBD supplementation in a six-arm placebo-controlled crossover study after resistance training on performance and muscle damage. Before and after the resistance training, one-repetition maximum in the back squat (1RM BS), countermovement jump (CMJ), and blood serum concentrations of creatine kinase (CK) and myoglobin (Myo) were measured in healthy, well-trained participants. 16 out of 21 participants completed the study and were included in the analysis. In 1RM BS, a significant decrease was observed after 24 h (p < 0.01) but not after 48 and 72 h. A significant group difference was detected after 72 h (p < 0.05; ES = 0.371). In CMJ, no significant changes were observed. The CK and Myo concentrations increased significantly after 24 h (CK: p < 0.001; Myo: p < 0.01), 48 h (CK: p < 0.001; Myo: p < 0.01) and 72 h (CK: p < 0.001; Myo: p < 0.001). After 72 h, significant group differences were observed for both muscle damage biomarkers (CK: p < 0.05 ES = 0.24; Myo: p < 0.05; ES = 0.21). The results show small but significant effects on muscle damage and recovery of squat performance after 72 h. However, more data are required for clearer statements concerning potential pro-regenerative effects of CBD supplementation after resistance training.