Evidence has shown that protein supplementation following resistance exercise training (RET) helps to further enhance muscle mass and strength. Studies have demonstrated that collagen peptides containing mostly non-essential amino acids increase fat-free mass (FFM) and strength in sarcopenic men. The aim of this study was to investigate whether collagen peptide supplementation in combination with RET influences the protein composition of skeletal muscle. Twenty-five young men (age: 24.2 ± 2.6 years, body mass (BM): 79.6 ± 5.6 kg, height: 185.0 ± 5.0 cm, fat mass (FM): 11.5% ± 3.4%) completed body composition and strength measurements and vastus lateralis biopsies were taken before and after a 12-week training intervention. In a double-blind, randomized design, subjects consumed either 15 g of specific collagen peptides (COL) or a non-caloric placebo (PLA) every day within 60 min after their training session. A full-body hypertrophy workout was completed three times per week and included four exercises using barbells. Muscle proteome analysis was performed by liquid chromatography tandem mass spectrometry (LC-MS/MS). BM and FFM increased significantly in COL compared with PLA, whereas no differences in FM were detected between the two groups. Both groups improved in strength levels, with a slightly higher increase in COL compared with PLA. In COL, 221 higher abundant proteins were identified. In contrast, only 44 proteins were of higher abundance in PLA. In contrast to PLA, the upregulated proteins in COL were mostly associated with the protein metabolism of the contractile fibers. In conclusion, the use of RET in combination with collagen peptide supplementation results in a more pronounced increase in BM, FFM, and muscle strength than RET alone. More proteins were upregulated in the COL intervention most of which were associated with contractile fibers.

We aimed to determine the effects of long-term collagen peptide (CP) supplementation and resistance exercise training (RET) on body composition, strength, and muscle fiber cross-sectional area (fCSA) in recreationally active men. Fifty-seven young men were randomly and double-blinded divided into a group receiving either collagen peptides (COL, 15 g/day) or a placebo (PLA). Strength testing, bioimpedance analysis, and muscle biopsies were used prior to and after an RET intervention. Food record protocols were performed during the RET intervention. The groups trained three times a week for 12 weeks. Baseline parameters showed no differences between groups, and the external training load and dietary food intake were also similar. COL showed a significant increase in fat-free mass (FFM) compared with the placebo group (p < 0.05). Body fat mass (BFM) was unchanged in COL, whereas a significant increase in BFM was observed in PLA. Both groups showed significant increases in all strength tests, with a trend for a slightly more pronounced effect in COL. The fCSA of type II muscle fibers increased significantly in both groups without differences between the two groups. We firstly demonstrated improved body composition in healthy, recreationally active men subsequent to prolonged CP supplementation in combination with RET. As the observed increase in FFM was not reflected in differences in fCSA hypertrophy between groups, we assume enhanced passive connective tissue adaptations in COL due to CP intake.

Background/Objectives: Low energy availability (LEA) can cause impaired reproductive function, bone health issues, and suppressed immune function, and may result in decreased performance and overall health status. The purpose of this study was to investigate adaptions of body composition, blood status, resting metabolic rate, and endurance performance to gain more comprehensive insights into the symptoms of LEA and the adaptive effects in the athlete population (active women (n = 11) and men (n = 11)). Methods: Three treatments were defined as 45 (EA45, control), 30 (EA30), and 10 (EA10) kcal/kg FFM/day and randomly assigned. Pre- and post-intervention measurements were performed through blood sampling, bioelectrical impedance analysis, resting metabolic rate measurement, the oral glucose tolerance test (OGTT), and the incremental endurance test to exhaustion. Results: There was a significant reduction in body weight and fat mass in EA10 compared to EA45 (p ≤ 0.05). Blood serum levels were altered in triglyceride, uric acid, and creatinine concentrations in EA10 compared to EA45 (p ≤ 0.05). Furthermore, blood glucose was still accumulated after 120 min during OGTT in EA10 compared to EA45 (p ≤ 0.05). The respiratory exchange ratio was reduced during submaximal stages of the incremental treadmill test to exhaustion without influencing performance output after treatment EA10 (p ≤ 0.05). However, the resting metabolic rate did not change (p > 0.05). Conclusions: In conclusion, this short-term study indicates that energy restriction can lead to several metabolic-related adaptations, which suggests that the availability and regulation of glucose and fats are significantly influenced after only five days of LEA in physically active women and men. Future research should focus on longer exposures of LEA and sex-specific comparisons (including the menstrual cycle) on LEA symptoms.

Introduction: Protein supplementation increases postexercise muscle protein synthesis rates and, as such, supports exercise-induced muscle conditioning. Collagen protein has been suggested as the preferred protein source to stimulate muscle connective protein synthesis rates during recovery from exercise. Here we assessed the effects of hydrolyzed collagen peptide supplementation on both myofibrillar as well as muscle connective protein synthesis rates during 1 wk of strenuous resistance exercise training. Methods: In a randomized, double-blind, parallel design, 25 young men (24 ± 3 yr, 76.9 ± 6.4 kg) were selected to perform 1 wk of intense resistance–type exercise training. Subjects were randomly assigned into two groups receiving either 15 g hydrolyzed collagen peptides (COL) or a noncaloric placebo (PLA) twice daily during the intervention. Subjects were administered deuterated water (²H₂O) daily, with blood and skeletal muscle tissue samples being collected before and after the intervention to determine daily myofibrillar and muscle connective protein synthesis rates. Results: Post-absorptive plasma glycine, proline, and hydroxyproline concentrations increased following collagen peptide supplementation (P < 0.05) and showed higher levels when compared with the placebo group (P < 0.05). Daily muscle connective protein synthesis rates during the intervention period exceeded myofibrillar protein synthesis rates (1.99 ± 0.38 vs 1.34 ± 0.23%·d⁻¹, respectively; P < 0.001). Collagen peptide supplementation did not result in higher myofibrillar or muscle connective protein synthesis rates (1.34 ± 0.19 and 1.97 ± 0.47%·d⁻¹, respectively) when compared with the placebo group (1.34 ± 0.27 and 2.00 ± 0.27%·d⁻¹, respectively; P > 0.05). Conclusions: Collagen peptide supplementation (2 × 15 g daily) does not increase myofibrillar or muscle connective protein synthesis rates during 1 wk of intense resistance exercise training in young, recreational athletes.

Problem: There is a growing body of research investigating a variety of parameters affected by collagen peptide (CP) supplementation during structured exercise programs. The aim of this review is to focus on the musculoskeletal performance outcomes potentially affected by CP intake in healthy adults. Methods: A comprehensive literature search using defined MeSH terms was conducted in four databases (PubMed, Web of Science, EBSCO and Cochrane) by two independent reviewers. The resulting studies were used for systematic review and a random-effects meta-analysis. Results: A total of 13 studies were included in this review. Two primary study objectives were identified, categorizing studies into those focusing on a potential effect of CP intake on adaptation to training stimuli and those focusing on recovery from training stimuli. Nine of these studies were used for in-depth meta-analysis. Of the 55 performance parameters extracted, 48 were unaffected by additional CP intake. Furthermore, the meta-analysis revealed no significant effect of CP on strength-related performance parameters (SMD=0.079 [-0.120 to 0.273], p=0.445). Discussion: The studies included show a high degree of homogeneity in most methodological aspects and have a low risk of biased results, which supports the validity of the results found. Nevertheless, this result represents the current state of scientific knowledge. Conclusion: The qualitative and quantitative analysis of the available studies suggests the ineffectiveness of CP supplementation in addition to exercise to further improve musculoskeletal performance.