Oral Supplementation of Specific Collagen Peptides Combined with Calf-Strengthening Exercises Enhances Function and Reduces Pain in Achilles Tendinopathy Patients

Antifibrotic and Pro-regenerative Effects of SMAD3 siRNA and Collagen I mRNA-Loaded Lipid Nanoparticles in Human Tenocytes

Tendinopathy involves the inflammation and degeneration of the tendon due to repetitive strain injury. Current treatments primarily target inflammation resolution, yet they do not aim at tissue regeneration. In this study, a microfluidics approach is harnessed to develop a platform of lipid nanoparticles (LNPs) loaded simultaneously with SMAD3 siRNA and collagen I mRNA, aiming to explore its potential dual antifibrotic and regenerative effects in human tenocytes. The developed LNPs displayed size homogeneity and colloidal stability and exhibited high cytocompatibility in human tenocytes. Moreover, LNPs allowed for efficient uptake and transfection efficiency of the RNAs. In the in vitro efficacy studies, the gene expression and production of SMAD3 and collagen I were tested by real-time quantitative chain polymerase reaction and immuno- and intracellular staining, revealing collagen I production enhancement, SMAD3 inhibition, and modulation of other tendon repair factors by the LNPs. Overall, the potential of this platform of RNA-loaded LNPs to be used as a dual therapeutic approach to prevent fibrosis and promote tissue remodeling in late stages of tendon diseases was confirmed.

Collagen peptide supplementation before bedtime reduces sleep fragmentation and improves cognitive function in physically active males with sleep complaints

PURPOSE

The primary aim of this study was to examine whether a glycine-rich collagen peptides (CP) supplement could enhance sleep quality in physically active men with self-reported sleep complaints.

METHODS

In a randomized, crossover design, 13 athletic males (age: 24 ± 4 years; training volume; 7 ± 3 h·wk1) with sleep complaints (Athens Insomnia Scale, 9 ± 2) consumed CP (15 g·day1) or a placebo control (CON) 1 h before bedtime for 7 nights. Sleep quality was measured with subjective sleep diaries and actigraphy for 7 nights; polysomnographic sleep and core temperature were recorded on night 7. Cognition, inflammation, and endocrine function were measured on night 7 and the following morning. Subjective sleepiness and fatigue were measured on all 7 nights. The intervention trials were separated by ≥ 7 days and preceded by a 7-night familiarisation trial.

RESULTS

Polysomnography showed less awakenings with CP than CON (21.3 ± 9.7 vs. 29.3 ± 13.8 counts, respectively; P = 0.028). The 7-day average for subjective awakenings were less with CP vs. CON (1.3 ± 1.5 vs. 1.9 ± 0.6 counts, respectively; P = 0.023). The proportion of correct responses on the baseline Stroop cognitive test were higher with CP than CON (1.00 ± 0.00 vs. 0.97 ± 0.05 AU, respectively; P = 0.009) the morning after night 7. There were no trial differences in core temperature, endocrine function, inflammation, subjective sleepiness, fatigue and sleep quality, or other measures of cognitive function or sleep (P > 0.05).

CONCLUSION

CP supplementation did not influence sleep quantity, latency, or efficiency, but reduced awakenings and improved cognitive function in physically active males with sleep complaints.

Specific collagen peptides increase adaptions of patellar tendon morphology following 14-weeks of high-load resistance training: A randomized-controlled trial

ABSTRACTThe purpose of this study was to investigate the effect of a supplementation with specific collagen peptides (SCP) combined with resistance training (RT) on changes in structural properties of the patellar tendon. Furthermore, tendon stiffness as well as maximal voluntary knee extension strength and cross-sectional area (CSA) of the rectus femoris muscle were assessed. In a randomized, placebo-controlled study, 50 healthy, moderately active male participants completed a 14-week resistance training program with three weekly sessions (70-85% of 1 repetition maximum [1RM]) for the knee extensors. While the SCP group received 5g of specific collagen peptides daily, the other group received the same amount of a placebo (PLA) supplement. The SCP supplementation led to a significant greater (p < 0.05) increase in patellar tendon CSA compared with the PLA group at 60% and 70% of the patellar tendon length starting from the proximal insertion. Both groups increased tendon stiffness (p < 0.01), muscle CSA (p < 0.05) and muscular strength (p < 0.001) throughout the intervention without significant differences between the groups. The current study shows that in healthy, moderately active men, supplementation of SCP in combination with RT leads to greater increase in patellar tendon CSA than RT alone. Since underlying mechanisms of tendon hypertrophy are currently unknown, further studies should investigate potential mechanisms causing the increased morphology adaptions following SCP supplementation.Trial registration: German Clinical Trials Register identifier: DRKS00029244..

Collagen peptides supplementation improves function, pain, and physical and mental outcomes in active adults

INTRODUCTION

Chronic pain affects 19% of adults in the United States, with increasing prevalence in active and aging populations. Pain can limit physical activity and activities of daily living (ADLs), resulting in declined mental and social health. Nutritional interventions for pain currently target inflammation or joint health, but few influence both. Collagen, the most abundant protein in the human body and constituent of the extra cellular matrix, is such a nutraceutical. While there have been reports of reductions in pain with short-term collagen peptide (CP) supplementation, there are no long-term studies specifically in healthy middle-aged active adults.

PURPOSE

To determine the effects of daily CP consumption over 3, 6, and 9 months on survey measures of pain, function, and physical and mental health using The Knee Injury & Osteoarthritis Outcomes Score (KOOS) and Veterans Rand 12 (VR-12) in middle-aged active adults.

METHODS

This study was a double-blind randomized control trial with three treatment groups (Placebo, 10 g/d CP, and 20 g/d CP).

RESULTS

Improvements in ADLs (p = .031, ηp2 = .096) and pain (p = .037, ηp2 = .164) were observed with 10 g/d CP over 6 months, although pain only improved in high frequency exercisers (>180 min/week). Additionally, VR-12 mental component scores (MCS) improved with 10 g/d of CP over 3-9 months (p = .017, ηp2 = .309), while physical component scores (PCS) improved with 20 g/d of CP over 3-9 months, but only in females (p = .013, ηp2= .582).

CONCLUSION

These findings suggest 10 to 20 g/d of CP supplementation over 6 to 9 months may improve ADLs, pain, MCS, and PCS in middle-aged active adults.

The JUMPFOOD study: additional effect of hydrolyzed collagen and vitamin C to exercise treatment for patellar tendinopathy (jumper's knee) in athletes-study protocol for a double-blind randomized controlled trial

BACKGROUND

Patellar tendinopathy (PT) is a common problem in jumping athletes. Management can be challenging and treatment outcome is not always successful. In combination with tendon loading exercises, hydrolyzed collagen/vitamin C supplementation appears to have a promising effect on the recovery of tendinopathy. The aim of this study is to evaluate whether the use of oral supplementation of hydrolyzed collagen and vitamin C in combination with progressive tendon loading exercises (PTLE) is superior to PTLE and placebo on VISA-P score (which rates pain, function, sports participation) after 24 weeks for athletes with PT.

METHODS

The JUMPFOOD study is a double-blinded, two-armed randomized controlled trial, in which the effectiveness of oral supplementation of hydrolyzed collagen/vitamin C combined with PTLE compared to PTLE with placebo on pain and recovery of function in athletes with PT will be investigated. Seventy-six athletes aged 16-40 years, with symptoms of PT for at least 12 weeks, who play sports at least once a week will be included. All participants will receive education, advice with regard to load management and a PTLE program according to the Dutch guidelines for anterior knee pain. In addition, the intervention group will receive daily 10 g hydrolyzed collagen and 40 mg vitamin C supplementation for 24 weeks whereas the control group receives 10 g maltodextrin placebo supplementation. Measurements will take place at baseline and at 12 and 24 weeks' follow-up. Primary outcome is the VISA-P score, which evaluates pain, function, and sports participation. For secondary outcome measures, data with regard to pain during functional tests, flexibility measurements, blood withdrawals, imaging characteristics of the tendon, and health questionnaires will be collected. During the follow-up period, participants will register sports participation, amount of training and tendon load, pain during sports, co-medication, and side-effects in a digital weekly diary.

DISCUSSION

The JUMPFOOD study is the first large RCT to study the effectiveness of hydrolyzed collagen/vitamin C supplementation in combination with the PTLE program in athletes with patellar tendinopathy. If supplementation of collagen/vitamin C appears to be effective, this treatment can be implemented in daily sports medicine practice to improve the treatment outcome of patients with PT.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05407194. Registered on 7 June 2022.

Anti-Adhesive Resorbable Indomethacin/Bupivacaine-Eluting Nanofibers for Tendon Rupture Repair: In Vitro and In Vivo Studies

The treatment and surgical repair of torn Achilles tendons seldom return the wounded tendon to its original elasticity and stiffness. This study explored the in vitro and in vivo simultaneous release of indomethacin and bupivacaine from electrospun polylactide-polyglycolide composite membranes for their capacity to repair torn Achilles tendons. These membranes were fabricated by mixing polylactide-polyglycolide/indomethacin, polylactide-polyglycolide/collagen, and polylactide-polyglycolide/bupivacaine with 1,1,1,3,3,3-hexafluoro-2-propanol into sandwich-structured composites. Subsequently, the in vitro pharmaceutic release rates over 30 days were determined, and the in vivo release behavior and effectiveness of the loaded drugs were assessed using an animal surgical model. High concentrations of indomethacin and bupivacaine were released for over four weeks. The released pharmaceutics resulted in complete recovery of rat tendons, and the nanofibrous composite membranes exhibited exceptional mechanical strength. Additionally, the anti-adhesion capacity of the developed membrane was confirmed. Using the electrospinning technique developed in this study, we plan on manufacturing degradable composite membranes for tendon healing, which can deliver sustained pharmaceutical release and provide a collagenous habitat.

Effects of Specific Bioactive Collagen Peptides in Combination with Concurrent Training on Running Performance and Indicators of Endurance Capacity in Men: A Randomized Controlled Trial

BACKGROUND

First evidence indicates that the supplementation of specific collagen peptides (SCP) is associated with a significant improvement in running performance in physically active women; however, it is unclear if the same is true in males. The purpose of the present study was to investigate the effects of a concurrent training program including 60 min of continuous moderate intensity running training and 15 min of dynamic resistance training combined with supplementation of SCP on parameters of running performance in moderately trained males.

METHODS

In a double-blind, placebo-controlled, randomized trial, participants performed a 12 weeks concurrent training and ingested 15 g of SCP [treatment group (TG)] or placebo [control group (CG)] daily. Before and after the intervention, running endurance performance was measured by a 1-h time trial on a running track. Velocity at the lactate threshold (VLT) and at the individual anaerobic threshold (VIAT) were assessed on a treadmill ergometer. Body composition was evaluated by bioelectrical impedance analysis.

RESULTS

Thirty-two men (28.4 ± 5.2 years) completed the study and were included in the analysis. After 12 weeks, TG had a statistically significant (p ≤ 0.05) higher increase in running distance (1727 ± 705 m) compared to the CG (1018 ± 976 m) in the time trial. VLT increased in the TG by 0.680 ± 1.27 km h-1 and slightly decreased by - 0.135 ± 0.978 km h-1 in the CG, resulting in statistically significant group differences (p ≤ 0.05). A significantly higher improvement in VIAT (p ≤ 0.05) was shown in the TG compared with the CG only (1.660 ± 1.022 km h-1 vs 0.606 ± 0.974 km h-1; p ≤ 0.01). Fat mass decreased (TG - 1.7 ± 1.6 kg; CG - 1.2 ± 2.0 kg) and fat free mass increased (TG 0.2 ± 1.2 kg; CG 0.5 ± 1.3 kg) in both groups with no significant group differences.

CONCLUSION

In summary, supplementation with 15 g of SCP improved running performance in a 1-h time trial and enhanced indicators of endurance capacity at submaximal exercise intensities such as an increased velocity at the lactate as well as the anaerobic threshold more effectively than CT alone.

TRIAL REGISTRATION

ETK: 123/17; DRKS-ID: DRKS00015529 (Registered 07 November 2018-Retrospectively registered); https://drks.de/search/de/trial/DRKS00015529.

The Effect of Specific Bioactive Collagen Peptides on Tendon Remodeling during 15 wk of Lower Body Resistance Training

PURPOSE

Collagen peptide supplementation has been reported to enhance synthesis rates or growth in a range of musculoskeletal tissues and could enhance tendinous tissue adaptations to resistance training (RT). This double-blind placebo-controlled study aimed to determine if tendinous tissue adaptations, size (patellar tendon cross-sectional area (CSA) and vastus lateralis (VL) aponeurosis area), and mechanical properties (patellar tendon), after 15 wk of RT, could be augmented with collagen peptide (CP) versus placebo (PLA) supplementation.

METHODS

Young healthy recreationally active men were randomized to consume either 15 g of CP ( n = 19) or PLA ( n = 20) once every day during a standardized program of lower-body RT (3 times a week). Measurements pre- and post-RT included patellar tendon CSA and VL aponeurosis area (via magnetic resonance imaging), and patellar tendon mechanical properties during isometric knee extension ramp contractions.

RESULTS

No between-group differences were detected for any of the tendinous tissue adaptations to RT (ANOVA group-time, 0.365 ≤ P ≤ 0.877). There were within-group increases in VL aponeurosis area (CP, +10.0%; PLA, +9.4%), patellar tendon stiffness (CP, +17.3%; PLA, +20.9%) and Young's modulus (CP, +17.8%; PLA, +20.6%) in both groups (paired t -tests (all), P ≤ 0.007). There were also within-group decreases in patellar tendon elongation (CP, -10.8%; PLA, -9.6%) and strain (CP, -10.6%; PLA, -8.9%) in both groups (paired t -tests (all), P ≤ 0.006). Although no within-group changes in patellar tendon CSA (mean or regional) occurred for CP or PLA, a modest overall time effect ( n = 39) was observed for mean (+1.4%) and proximal region (+2.4%) patellar tendon CSA (ANOVA, 0.017 ≤ P ≤ 0.048).

CONCLUSIONS

In conclusion, CP supplementation did not enhance RT-induced tendinous tissue remodeling (either size or mechanical properties) compared with PLA within a population of healthy young men.

Effects of Collagen and Exercise on Tendon Properties and Pain: A Critically Appraised Topic

CLINICAL SCENARIO

Achilles tendon ruptures are prevalent and devastating injuries that require the need for extensive rehabilitation. The methods for preventing these injuries vary between different exercise methods and nutritional supplementation. Although proven effective for decreasing pain and increasing tendon properties, the influence of these 2 methods in combination has not yet been evaluated.

CLINICAL QUESTION

Does exercise combined with collagen supplementation improve Achilles tendon structural and mechanical properties and diminish subsequent patient-reported pain compared with exercise alone in adults?

SUMMARY OF KEY FINDINGS

Exercise training, including eccentric training protocols and concentric resistance training protocols, combined with collagen supplementation influence Achilles tendon properties and subsequent patient-reported pain compared with exercise alone.

CLINICAL BOTTOM LINE

Evidence supports that collagen along with exercise training has a significant influence on pain mitigation, augmented cross-sectional area, and tendon thickness, but may have little to no influence on tendon stiffness and microvascularity compared with exercise alone. Further research is needed to determine the effects of combined methods on various populations.

STRENGTH OF RECOMMENDATION

Collectively, the body of evidence included to answer the clinical question aligns with the strength of recommendation of A.

Exercise therapy for tendinopathy: a mixed-methods evidence synthesis exploring feasibility, acceptability and effectiveness

Background

Tendinopathy is a common, painful and functionally limiting condition, primarily managed conservatively using exercise therapy.

Review questions

(i) What exercise interventions have been reported in the literature for which tendinopathies? (ii) What outcomes have been reported in studies investigating exercise interventions for tendinopathy? (iii) Which exercise interventions are most effective across all tendinopathies? (iv) Does type/location of tendinopathy or other specific covariates affect which are the most effective exercise therapies? (v) How feasible and acceptable are exercise interventions for tendinopathies?

Methods

A scoping review mapped exercise interventions for tendinopathies and outcomes reported to date (questions i and ii). Thereafter, two contingent systematic review workstreams were conducted. The first investigated a large number of studies and was split into three efficacy reviews that quantified and compared efficacy across different interventions (question iii), and investigated the influence of a range of potential moderators (question iv). The second was a convergent segregated mixed-method review (question v). Searches for studies published from 1998 were conducted in library databases (n = 9), trial registries (n = 6), grey literature databases (n = 5) and Google Scholar. Scoping review searches were completed on 28 April 2020 with efficacy and mixed-method search updates conducted on 19 January 2021 and 29 March 2021.

Results

Scoping review - 555 included studies identified a range of exercise interventions and outcomes across a range of tendinopathies, most commonly Achilles, patellar, lateral elbow and rotator cuff-related shoulder pain. Strengthening exercise was most common, with flexibility exercise used primarily in the upper limb. Disability was the most common outcome measured in Achilles, patellar and rotator cuff-related shoulder pain; physical function capacity was most common in lateral elbow tendinopathy. Efficacy reviews - 204 studies provided evidence that exercise therapy is safe and beneficial, and that patients are generally satisfied with treatment outcome and perceive the improvement to be substantial. In the context of generally low and very low-quality evidence, results identified that: (1) the shoulder may benefit more from flexibility (effect sizeResistance:Flexibility = 0.18 [95% CrI 0.07 to 0.29]) and proprioception (effect sizeResistance:Proprioception = 0.16 [95% CrI -1.8 to 0.32]); (2) when performing strengthening exercise it may be most beneficial to combine concentric and eccentric modes (effect sizeEccentricOnly:Concentric+Eccentric = 0.48 [95% CrI -0.13 to 1.1]; and (3) exercise may be most beneficial when combined with another conservative modality (e.g. injection or electro-therapy increasing effect size by ≈0.1 to 0.3). Mixed-method review - 94 studies (11 qualitative) provided evidence that exercise interventions for tendinopathy can largely be considered feasible and acceptable, and that several important factors should be considered when prescribing exercise for tendinopathy, including an awareness of potential barriers to and facilitators of engaging with exercise, patients' and providers' prior experience and beliefs, and the importance of patient education, self-management and the patient-healthcare professional relationship.

Limitations

Despite a large body of literature on exercise for tendinopathy, there are methodological and reporting limitations that influenced the recommendations that could be made.

Conclusion

The findings provide some support for the use of exercise combined with another conservative modality; flexibility and proprioception exercise for the shoulder; and a combination of eccentric and concentric strengthening exercise across tendinopathies. However, the findings must be interpreted within the context of the quality of the available evidence.

Future work

There is an urgent need for high-quality efficacy, effectiveness, cost-effectiveness and qualitative research that is adequately reported, using common terminology, definitions and outcomes.

Study registration

This project is registered as DOI: 10.11124/JBIES-20-00175 (scoping review); PROSPERO CRD 42020168187 (efficacy reviews); https://osf.io/preprints/sportrxiv/y7sk6/ (efficacy review 1); https://osf.io/preprints/sportrxiv/eyxgk/ (efficacy review 2); https://osf.io/preprints/sportrxiv/mx5pv/ (efficacy review 3); PROSPERO CRD42020164641 (mixed-method review).

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) HTA programme and will be published in full in HTA Journal; Vol. 27, No. 24. See the NIHR Journals Library website for further project information.

Nutritional Supplements in the Clinical Management of Tendinopathy: A Scoping Review

INTRODUCTION

Tendinopathy has a high prevalence and incidence in the general population and among athletes, with a lack of consensus among medical practitioners on optimal management strategies. The objective of this scoping review was to evaluate current research on the use of nutritional supplements for treating tendinopathies, including what supplements have been used and what outcomes, outcome measures, and intervention parameters have been reported.

METHODS

Databases searched included Embase, SPORTDiscus, the Cochrane Library, MEDLINE, CINAHL, and AMED. This scoping review considered primary studies investigating nutritional supplements for tendinopathies and was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews.

RESULTS

A total of 1527 articles were identified with 16 included in the review. Studies investigated a range of nutritional supplements in the clinical management of various tendinopathies, including several commercially available proprietary blends of several ingredients. TendoActive (mucopolysaccharides, type I collagen, and vitamin C) was used in 2 studies, TENDISULFUR (methylsulfonylmethane, hydrolyzed collagen, L-arginine, L-lysine, vitamin C, bromelain, chondroitin, glucosamine, Boswellia, and myrrh) was used in 3 studies, and Tenosan (arginine-L-alpha ketoglutarate, hydrolyzed collagen type I, methylsulfonylmethane, vitamin C, bromelain, and vinitrox) was used in 2 studies. Collagen peptides were used in 2 studies, with omega-3 fatty acids, combined fatty acids and antioxidants, turmeric rhizome combined with Boswellia, β-hydroxy β-methylbutyric, vitamin C in isolation and combined with gelatin, and creatine investigated in one study each.

CONCLUSION

Despite a paucity of studies to date, findings from this review suggest that several nutritional compounds may be beneficial in the clinical management of tendinopathies, by exerting anti-inflammatory effects and improving tendon healing. Nutritional supplements may have potential as an adjunctive method to standard treatment methods such as exercise, where their pain-relieving, anti-inflammatory, and structural tendon effects may augment the positive functional outcomes gained from progressive exercise rehabilitation.

Impact of essential amino acid intake, resistance exercise, and aging on the concentration of Achilles peritendinous amino acids and procollagen Iα1 in humans

Recent studies have shown that consuming amino acid-rich compounds improves tendon collagen content and biomechanical properties. Yet, it is unclear if the consumption of amino acids alters local (peritendinous) amino acid concentrations. If aging or exercise influence local amino acid concentrations in conjunction with an amino acid bolus is also not known. We conducted two studies. In Study 1, young women (n = 7, 25 ± 2 years) completed two identical resistance training sessions with either essential amino acid (EAA) or placebo consumption. In Study 2, an EAA bolus identical to Study 1 was given to younger (n = 7; 27 ± 1 year) and older adults (n = 6; 68 ± 2 years). Microdialysis was used to determine Achilles peritendinous amino acid and pro-collagen Iα1 (a marker of collagen synthesis) concentrations. In Study 1, amino acid consumption increased peritendinous concentrations of all EAA except histidine (p < 0.05). In Study 2, the peritendinous concentration of EAAs except for methionine, histidine, and lysine (p > 0.05) increased with time (p < 0.05). Further, the concentrations of most measured amino acids were greater in older adults (p < 0.05). Pro-collagen Iα1 concentration (p > 0.05) was unaffected by exercise, EAA, or aging (p > 0.05). Our findings demonstrate the following: (1) when not combined with exercise, an oral EAA bolus leads to only modest increases in Achilles peritendinous amino acid concentrations; (2) when combined with resistance exercise, EAA consumption resulted in greater peritendinous amino acid concentrations compared to no exercise; (3) the basal concentrations of most amino acids were greater in older adults, and (4) neither the EAA bolus nor exercise altered peritendinous pro-collagen concentrations.

Collagen supplementation in skin and orthopedic diseases: A review of the literature

Collagen is one of the main components of the extracellular matrix of the dermis and articular cartilage and influences the body's mechanical, organizational, and tissue formation properties. Produced from food industry by-products, it is considered a nutraceutical product widely used as an ingredient or supplement in food, pharmaceutical, and cosmetic industries. This study aimed to conduct a literature review on the scientific evidence regarding the beneficial effects of collagen consumption in the treatment of skin and orthopedic diseases. Literature data have shown that hydrolyzed collagen supplementation promotes skin changes, such as decreased wrinkle formation; increased skin elasticity; increased hydration; increased collagen content, density, and synthesis, which are factors closely associated with aging-related skin damage. Regarding orthopedic changes, collagen supplementation increases bone strength, density, and mass; improves joint stiffness/mobility, and functionality; and reduces pain. These aspects are associated with bone loss due to aging and damage caused by strenuous physical activity. Thus, this review addresses the economic and health potential of this source of amino acids and bioactive peptides extracted from food industry by-products.

The effect of specific bioactive collagen peptides on function and muscle remodeling during human resistance training

AIM

Bioactive collagen peptides (CP) have been suggested to augment the functional, structural (size and architecture), and contractile adaptations of skeletal muscle to resistance training (RT), but with limited evidence. This study aimed to determine if CP vs. placebo (PLA) supplementation enhanced the functional and underpinning structural, and contractile adaptations after 15 weeks of lower body RT.

METHODS

Young healthy males were randomized to consume either 15 g of CP (n = 19) or PLA (n = 20) once every day during a standardized program of progressive knee extensor, knee flexor, and hip extensor RT 3 times/wk. Measurements pre- and post-RT included: knee extensor and flexor isometric strength; quadriceps, hamstrings, and gluteus maximus volume with MRI; evoked twitch contractions, 1RM lifting strength, and architecture (with ultrasound) of the quadriceps.

RESULTS

Percentage changes in maximum strength (isometric or 1RM) did not differ between-groups (0.684 ≤ p ≤ 0.929). Increases in muscle volume were greater (quadriceps 15.2% vs. 10.3%; vastus medialis (VM) 15.6% vs. 9.7%; total muscle volume 15.7% vs. 11.4%; [all] p ≤ 0.032) or tended to be greater (hamstring 16.5% vs. 12.8%; gluteus maximus 16.6% vs. 12.9%; 0.089 ≤ p ≤ 0.091) for CP vs. PLA. There were also greater increases in twitch peak torque (22.3% vs. 12.3%; p = 0.038) and angle of pennation of the VM (16.8% vs. 5.8%, p = 0.046), but not other muscles, for CP vs. PLA.

CONCLUSIONS

CP supplementation produced a cluster of consistent effects indicating greater skeletal muscle remodeling with RT compared to PLA. Notably, CP supplementation amplified the quadriceps and total muscle volume increases induced by RT.

Perioperative Management in the Collegiate Athlete: An Integrated Approach

Collegiate athletes face rigorous physical, academic, and emotional demands. While significant attention has been paid to injury prevention among young athletes in the past two decades, orthopedic injury rates remain high among collegiate athletes, and a significant number will undergo surgical management for injuries each year. In this narrative review, we describe techniques for perioperative management of pain and stress after surgery in collegiate athletes. In particular, we outline pharmacologic and non-pharmacologic management of surgical pain, with a goal of minimizing opiate consumption. We emphasize a multi-disciplinary approach to optimizing post-operative recovery in collegiate athletes help minimize reliance on opiate pain medication. Additionally, we recommend that institutional resources should be harnessed to support athletes in their well-being, from a nutritional, psychological and sleep standpoint. Critical to success in perioperative pain management is the communication among the athletic medicine team members and with the athlete and family to address pain and stress management and encourage timely, safe return to play.

Collagen peptide supplementation for pain and function: is it effective?

PURPOSE OF REVIEW

Connective tissue injuries are prevalent in active and aging populations, leading to chronic pain and decreased function. Turnover of this tissue is not well understood, especially as it relates to aging and injury. Supplementation of collagen peptides has been shown to improve connective tissue recovery and pain through increased collagen production.

RECENT FINDINGS

Collagen peptide supplementation improves pain and function, and upregulates metabolic pathways associated with muscle and tendon growth. Literature from the past 12-18 months supports that these pathways are also involved with increased synthesis and degradation of collagen and other elements of the extracellular matrix. Improvements in body composition and strength have been noted with collagen peptide supplementation when paired with resistance training. Collagen peptide supplements are hydrolyzed into small peptides, termed bioactive peptides, and individual amino acids. These bioactive peptides are associated with the benefits observed with collagen peptide supplementation and may play a critical role in the collagen turnover.

SUMMARY

Collagen peptide supplementation has been shown to promote recovery, decrease pain, and improve strength and body composition when paired with resistance training. These benefits may be attributed to bioactive peptides in collagen peptide supplements. Additional research is warranted to examine the specific effects of these bioactive peptides.

Effects of specific collagen peptide supplementation combined with resistance training on Achilles tendon properties

The purpose of this study was to investigate the effect of specific collagen peptides (SCP) combined with resistance training (RT) on changes in tendinous and muscular properties. In a randomized, placebo-controlled study, 40 healthy male volunteers (age: 26.3 ± 4.0 years) completed a 14 weeks high-load resistance training program. One group received a daily dosage of 5g SCP while the other group received 5g of a placebo (PLA) supplement. Changes in Achilles tendon cross-sectional area (CSA), tendon stiffness, muscular strength, and thickness of the plantar flexors were measured. The SCP supplementation led to a significantly (p = 0.002) greater increase in tendon CSA (+11.0%) compared with the PLA group (+4.7%). Moreover, the statistical analysis revealed a significantly (p = 0.014) greater increase in muscle thickness in the SCP group (+7.3%) compared with the PLA group (+2.7%). Finally, tendon stiffness and muscle strength increased in both groups, with no statistical difference between the groups. In conclusion, the current study shows that the supplementation of specific collagen peptides combined with RT is associated with a greater hypertrophy in tendinous and muscular structures than RT alone in young physically active men. These effects might play a role in reducing tendon stress (i.e., deposition of collagen in load-bearing structures) during daily activities.

Management of tendinopathies among south Indians using collagen II peptide, glucosamine and vitamin C

Tendinopathy is a multi-factorial, broad spectrum of tendon disorder, characterized by activity-related chronic tendon pain and local tenderness. The point of this study was to assess the adequacy of a nutritional supplement containing Glucosamine, type II collagen and vitamin C on the clinical and auxiliary advancement of tendinopathies. The prospective study was Hospital based randomized control trail comparing the efficacy of collage 2 peptide, glucosamine and vitamin c with placebo in various tendinopathies. All diagnosed patients willing for the treatment attending Konaseema Institute of Medical Sciences during period of 2017-2019 were selected with regular follow up of 2nd week, 2nd month & 6 month. The statistics and visualizations of various observations made in the entire study which include a total of 80 patients with various tendinopathies. 60 of them were given collagen 2, glucosamine and vitamin c (cases) and 20 were given placebo (controls). At the end of 6 months almost 90% patients relieved completely of pain. The duration of maximum benefit to reach is almost around 24 weeks. These are seen more commonly to affect non-athletes rather than athletes.

Protein and Sport: Alternative Sources and Strategies for Bioactive and Sustainable Sports Nutrition

Nutrition and sport play an important role in achieving a healthy lifestyle. In addition to the intake of nutrients derived from the normal diet, some sport disciplines require the consumption of supplements that contribute positively to improved athletic performance. Protein intake is important for many aspects related to health, and current evidence suggests that some athletes require increased amounts of this nutrient. On the other hand, society's demand for more environmentally friendly products, focus on the search for alternative food sources more sustainable. This review aims to summarize the latest research on novel strategies and sources for greener and functional supplementation in sport nutrition. Alternative protein sources such as insects, plants or mycoproteins have proven to be an interesting substrate due to their high added value in terms of bioactivity and sustainability. Protein hydrolysis has proven to be a very useful technology to revalue by-products, such as collagen, by producing bioactive peptides beneficial on athletes performance and sport-related complications. In addition, it has been observed that certain amino acids from plant sources, as citrulline or theanine, can have an ergogenic effect for this target population. Finally, the future perspectives of protein supplementation in sports nutrition are discussed. In summary, protein supplementation in sports nutrition is a very promising field of research, whose future perspective lies with the search for alternatives with greater bioactive potential and more sustainable than conventional sources.

Effect of Collagen Types, Bacterial Strains and Storage Duration on the Quality of Probiotic Fermented Sheep’s Milk

Collagen has become popular in dietary supplements, beverages and sports nutrition products. Therefore, the aim of this study was to evaluate the possibility of using various doses of collagen and collagen hydrolysate to produce probiotic sheep’s milk fermented with Lactobacillus acidophilus, Lacticaseibacillus casei, Lacticaseibacillus paracasei and Lacticaseibacillus rhamnosus. The effects of storage time, type and dose of collagen, and different probiotic bacteria on the physicochemical, organoleptic and microbiological properties of fermented sheep’s milk at 1 and 21 days of refrigerated storage were investigated. The addition of collagen to sheep’s milk increased the pH value after fermentation and reduced the lactic acid contents of fermented milk compared to control samples. After fermentation, the number of probiotic bacteria cells was higher than 8 log cfu g⁻¹. In sheep’s milk fermented by L. acidophilus and L. casei, good survival of bacteria during storage was observed, and there was no effect of collagen dose on the growth and survival of both strains. The addition of collagen, both in the form of hydrolysate and bovine collagen, resulted in darkening of the color of the milk and increased the sweet taste intensity of the fermented sheep’s milk. However, the addition of hydrolysate was effective in reducing syneresis in each milk sample compared to its control counterpart.

Assessment of the reporting quality of resistance training interventions in randomised controlled trials for lower limb tendinopathy: A systematic review

OBJECTIVES

1. To describe what exercises and intervention variables are used in resistance training interventions in randomised controlled trials for lower limb tendinopathy 2. To assess completeness of reporting as assessed by the Consensus on Exercise Reporting Template (CERT) and the Toigo and Boutellier framework. 3. To assess the implementation of scientific resistance training principles. 4. To assess therapeutic quality of exercise interventions with the i-CONTENT tool.

DATA SOURCES

We searched MEDLINE, CINAHL, AMED, EMBase, SPORTDiscus, and the Cochrane library databases.

REVIEW METHODS

Systematic review of randomised controlled trials that reported using resistance exercises for lower limb tendinopathies.

RESULTS

We included 109 RCTs. Eccentric heel drops were the most common exercise (43 studies), followed by isotonic heel raises (21), and single leg eccentric decline squats (18). Reporting of exercise descriptor items from the Toigo and Boutellier framework ranged from 0-13, with an average score of 9/13, and only 7 studies achieved a full 13/13. Reporting of items from the CERT ranged from 0-18, with an average score of 14/19. No study achieved a full 19/19, however 5 achieved 18/19. Scoring for resistance training principles ranged from 1-10, with only 11 studies achieving 10/10. Reporting across studies for the i-CONTENT tool ranged from 2-7, with an average score of 5 across included studies. A total of 19 studies achieved a full 7/7 score. Less than 50% of studies achieved an overall low risk of bias, highlighting the methodological concerns throughout studies.

CONCLUSION

The reporting of exercise descriptors and intervention content was generally high across RCTs for lower limb tendinopathy, with most allowing exercise replication. However, reporting for some tendinopathies and content items such as adherence was poor, limiting optimal translation to clinical practice.

Does Additional Dietary Supplementation Improve Physiotherapeutic Treatment Outcome in Tendinopathy? A Systematic Review and Meta-Analysis

A systematic review and meta-analysis of randomized controlled trials was performed to evaluate the effects of dietary supplements in addition to physiotherapeutic treatment on pain and functional outcomes. PubMed, The Cochrane Library, Web of Science, and Embase were searched from inception to November 2021 (Prospero registration: CRD42021291951). Studies were eligible if the interventions consisted of physiotherapeutic approaches that were combined with dietary supplementation and if they reported measures of pain and/or function. Six studies were included in the meta-analysis. Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated and analysed using a Review Manager software. Subgroup analysis was performed to explore possible associations between the study characteristics and the effectiveness of the intervention. Additional dietary supplementation during physiotherapeutic treatment significantly improved the reduction in pain score (SMD = −0.74, 95% CI, −1.37 to −0.10; p < 0.05), while it had no effect on functional outcomes (SMD = 0.29, 95% CI, 0.00 to 0.58; p > 0.05). This systematic review and meta-analysis suggests that additional nutritional interventions may improve physiotherapeutic treatment outcomes in the management of tendinopathies.

Resistance Training Interventions for Lower Limb Tendinopathies: A Scoping Review of Resistance Training Reporting Content, Quality, and Scientific Implementation

The objectives of this scoping review were as follows: (1) to describe what exercises and intervention variables are used in resistance training interventions for lower limb tendinopathy,  (2) to assess the completeness of reporting as assessed by the Consensus on Exercise Reporting Template (CERT) and the Toigo and Boutellier framework, and (3) to assess the implementation of scientific resistance training principles. We searched MEDLINE, CINAHL, AMED, Embase, SPORTDiscus, and Cochrane Library databases. Randomized controlled trials, cohort studies, case series, case reports, and observational studies that reported using resistance exercises for lower limb tendinopathies were considered for inclusion, with 194 studies meeting the inclusion criteria. Completeness of the reporting of exercise descriptors and programme variables was assessed by the CERT and the Toigo and Boutellier framework. Reporting of exercise descriptor items from the Toigo and Boutellier framework ranged from 0 to 13, with an average score of 9/13, with only 9 studies achieving a full 13/13. Reporting of items from the CERT ranged from 0 to 18, with an average score of 13/19. No study achieved a full 19/19; however, 8 achieved 18/19. Scoring for resistance training principles ranged from 1 to 10, with only 14 studies achieving 10/10. Eccentric heel-drops were the most common exercise (75 studies), followed by isotonic heel raises (38), and single-leg eccentric decline squats (27). The reporting of exercise descriptors and intervention content was high across studies, with most allowing exercise replication, particularly for Achilles and patellar tendinopathy. However, reporting for some tendinopathies and content items such as adherence was poor, limiting optimal translation to clinical practice.

Comparing Effectiveness of Combination of Collagen Peptide Type-1, Low Molecular Weight Chondroitin Sulphate, Sodium Hyaluronate, and Vitamin-C Versus Oral Diclofenac Sodium in Achilles Tendinopathy: A Prospective Randomized Control Trial

Background

Achilles tendinopathy, a common cause of heel pain, is primarily considered mechanical in origin, but its pathogenesis and treatment lack consensus. Molecules such as collagen peptide type-1, low molecular weight chondroitin sulphate, sodium hyaluronate and vitamin C have been shown to act as building blocks of tendon structure, and oral supplementation of these have promising results in Achilles tendinopathy.

Methods

This study was a prospective randomized control trial to compare the effectiveness of oral diclofenac sodium versus a nutraceutical combination of collagen peptide type-1, chondroitin sulphate, sodium hyaluronate, and vitamin C in the treatment of Achilles tendinopathy on pain and ultrasonographic structures. A total of 40 patients satisfying inclusion and exclusion criteria were randomly allocated into two groups and were given the nutraceutical combination in group A and diclofenac sodium in group B. The patient evaluation was done at baseline, six-week, and 12-week intervals in terms of VAS (Visual Analogue Scale) and tendo-Achilles thickness by ultrasound.

Results

Both nutraceutical combination and diclofenac reduced pain in persons with Achilles tendinopathy. The nutraceutical combination had a statistically significant better outcome in reducing pain at the end of 12 weeks. On ultrasound, both the interventions reduced Achilles tendon anteroposterior and mediolateral thickness by the end of 12 weeks. Although there was no absolute significant intergroup difference, the percentage change was more in the nutraceutical group in the case of anteroposterior thickness.

Conclusion

Combining collagen peptide type-1, low molecular weight chondroitin sulphate, sodium hyaluronate, and vitamin C is more effective than oral diclofenac in controlling pain in Achilles tendinopathy.

Potential Relevance of Bioactive Peptides in Sports Nutrition

Bioactive peptides are physiologically active peptides mostly derived from proteins following gastrointestinal digestion, fermentation or hydrolysis by proteolytic enzymes. It has been shown that bioactive peptides can be resorbed in their intact form and have repeatedly been shown to have a positive effect on health-related parameters such as hypertension, dyslipoproteinemia, inflammation and oxidative stress. In recent years, there has been increasing evidence that biologically active peptides could also play an important role in sports nutrition. Current studies have shown that bioactive peptides could have a positive impact on changes in body composition and muscular performance, reduce muscle damage following exercise and induce beneficial adaptions within the connective tissue. In the following overview, potential mechanisms as well as possible limitations regarding the sports-related effect of bioactive peptides and their potential mechanisms are presented and discussed. In addition, practical applications will be discussed on how bioactive peptides can be integrated into a nutritional approach in sports to enhance athletic performance as well as prevent injuries and improve the rehabilitation process.

The impact of collagen protein ingestion on musculoskeletal connective tissue remodeling: a narrative review

Collagen is the central structural component of extracellular connective tissue, which provides elastic qualities to tissues. For skeletal muscle, extracellular connective tissue transmits contractile force to the tendons and bones. Connective tissue proteins are in a constant state of remodeling and have been shown to express a high level of plasticity. Dietary-protein ingestion increases muscle protein synthesis rates. High-quality, rapidly digestible proteins are generally considered the preferred protein source to maximally stimulate myofibrillar (contractile) protein synthesis rates. In contrast, recent evidence demonstrates that protein ingestion does not increase muscle connective tissue protein synthesis. The absence of an increase in muscle connective tissue protein synthesis after protein ingestion may be explained by insufficient provision of glycine and/or proline. Dietary collagen contains large amounts of glycine and proline and, therefore, has been proposed to provide the precursors required to facilitate connective tissue protein synthesis. This literature review provides a comprehensive evaluation of the current knowledge on the proposed benefits of dietary collagen consumption to stimulate connective tissue remodeling to improve health and functional performance.

The effects of collagen peptide supplementation on body composition, collagen synthesis, and recovery from joint injury and exercise: a systematic review

Collagen peptide supplementation (COL), in conjunction with exercise, may be beneficial for the management of degenerative bone and joint disorders. This is likely due to stimulatory effects of COL and exercise on the extracellular matrix of connective tissues, improving structure and load-bearing capabilities. This systematic review aims to evaluate the current literature available on the combined impact of COL and exercise. Following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, a literature search of three electronic databases—PubMed, Web of Science and CINAHL—was conducted in June 2020. Fifteen randomised controlled trials were selected after screening 856 articles. The study populations included 12 studies in recreational athletes, 2 studies in elderly participants and 1 in untrained pre-menopausal women. Study outcomes were categorised into four topics: (i) joint pain and recovery from joint injuries, (ii) body composition, (iii) muscle soreness and recovery from exercise, and (iv) muscle protein synthesis (MPS) and collagen synthesis. The results indicated that COL is most beneficial in improving joint functionality and reducing joint pain. Certain improvements in body composition, strength and muscle recovery were present. Collagen synthesis rates were elevated with 15 g/day COL but did not have a significant impact on MPS when compared to isonitrogenous higher quality protein sources. Exact mechanisms for these adaptations are unclear, with future research using larger sample sizes, elite athletes, female participants and more precise outcome measures such as muscle biopsies and magnetic imagery.

[Tendinopathies of the Achilles tendon]

Disorders of the Achilles tendon are among the most frequent musculoskeletal injuries in athletes as well as in the general population. It is very important to differentiate the different clinical pictures summarized under the general term achillodynia and to understand the pathogenesis in order to undertake the correct therapeutic measures. In the case of insertional tendinopathies in particular, a rheumatological origin should be clarified. Doppler ultrasound is the most important diagnostic tool. Evidence-based treatment methods include various training programs, shock wave treatment, diverse injection and surgical procedures, each of which are discussed in detail in this article.

The dipeptide prolyl-hydroxyproline promotes cellular homeostasis and lamellipodia-driven motility via active β1-integrin in adult tendon cells

Collagen-derived hydroxyproline (Hyp)-containing peptides have a variety of biological effects on cells. These bioactive collagen peptides are locally generated by the degradation of endogenous collagen in response to injury. However, no comprehensive study has yet explored the functional links between Hyp-containing peptides and cellular behavior. Here, we show that the dipeptide prolyl-4-hydroxyproline (Pro-Hyp) exhibits pronounced effects on mouse tendon cells. Pro-Hyp promotes differentiation/maturation of tendon cells with modulation of lineage-specific factors and induces significant chemotactic activity in vitro. In addition, Pro-Hyp has profound effects on cell proliferation, with significantly upregulated extracellular signal-regulated kinase phosphorylation and extracellular matrix production and increased type I collagen network organization. Using proteomics, we have predicted molecular transport, cellular assembly and organization, and cellular movement as potential linked-network pathways that could be altered in response to Pro-Hyp. Mechanistically, cells treated with Pro-Hyp demonstrate increased directional persistence and significantly increased directed motility and migration velocity. They are accompanied by elongated lamellipodial protrusions with increased levels of active β1-integrin-containing focal contacts, as well as reorganization of thicker peripheral F-actin fibrils. Pro-Hyp-mediated chemotactic activity is significantly reduced (p < 0.001) in cells treated with the mitogen-activated protein kinase kinase 1/2 inhibitor PD98059 or the α5β1-integrin antagonist ATN-161. Furthermore, ATN-161 significantly inhibits uptake of Pro-Hyp into adult tenocytes. Thus, our findings document the molecular basis of the functional benefits of the Pro-Hyp dipeptide in cellular behavior. These dynamic properties of collagen-derived Pro-Hyp dipeptide could lead the way to its application in translational medicine.

The implementation of resistance training principles in exercise interventions for lower limb tendinopathy: A systematic review

OBJECTIVES

The primary purpose of this systematic review is to examine the literature on resistance training interventions for lower limb tendinopathy to evaluate the proportion of interventions that implemented key resistance training principles (specificity, progression, overload, individualisation) and reported relevant prescription components (frequency, intensity, sets, repetitions) and reported intervention adherence.

METHODS

Two reviewers performed a systematic review after screening titles and abstracts based on eligibility criteria. Identified papers were obtained in full text, with data extracted regarding the implementation of resistance training principles. Included articles were evaluated by the Cochrane risk of bias tool, with a scoring tool out of 10 used for implementation and reporting of the 5 key principles. Scientific databases were searched in November 2020 and included Medline, CINAHL, AMED, and Sportsdiscus.

RESULTS

52 randomised controlled trials investigating resistance training in five different lower limb tendinopathies were included. Although most studies considered the principles of progression (92%) and individualisation (88%), only 19 studies (37%) appropriately described how this progression in resistance was achieved, and only 18 studies (35%) reported specific instruction on how individualisation was applied. Adherence was considered in 27 studies (52%), with only 17 studies (33%) reporting the levels of adherence. In the scoring criteria, only 5 studies (10%) achieved a total maximum score of 10, with 17 studies (33%) achieving a maximum score of 8 for implementing and reporting the principles of specificity, overload, progression and individualisation.

CONCLUSION

There is meaningful variability and methodological concerns regarding the application and reporting of resistance training principles, particularly progression and individualisation, along with intervention adherence throughout studies. Collectively, these findings have important implications for the prescription of current resistance training interventions, including the design and implementation of future interventions for populations with lower limb tendinopathies.

The Influence of Specific Bioactive Collagen Peptides on Body Composition and Muscle Strength in Middle-Aged, Untrained Men: A Randomized Controlled Trial

It has been shown that specific collagen peptides combined with resistance training (RT) improves body composition and muscle strength in elderly sarcopenic men. The main purpose of this RCT study was to investigate the efficacy of the identical specific collagen peptides combined with RT on body composition and muscle strength in middle-aged, untrained men. Furthermore, in the exploratory part of the study, these results were compared with another group that had received whey protein in addition to the RT. Ninety-seven men completed this study and participated in a 12-week RT program. They ingested 15 g of specific collagen peptides (n = 30; CP-G), placebo (n = 31; P-G), or whey protein (n = 36; WP-G) daily. Changes in fat free mass and fat mass were determined by dual-energy X-ray absorptiometry (DXA), and isometric leg strength was measured. All participants had significantly (p < 0.01) improved levels in fat free mass (ΔCP-G = 3.42 ± 2.54 kg; ΔP-G = 1.83 ± 2.09 kg; ΔWP-G = 2.27 ± 2.56 kg), fat mass (ΔCP-G = -5.28 ± 3.19 kg; ΔP-G = -3.39 ± 3.13 kg; ΔWP-G = -4.08 ± 2.80 kg) and leg strength (ΔCP-G = 163 ± 189 N; ΔP-G = 100 ± 154 N; ΔWP-G = 120 ± 233 N). The main analysis revealed a statistically significantly higher increase in fat free mass (p = 0.010) and decrease in fat mass (p = 0.023) in the CP-G compared with the P-G. The exploratory analysis showed no statistically significant differences between WP-G and CP-G or P-G, regarding changes of fat free mass and fat mass. In conclusion, specific collagen peptide supplementation combined with RT was associated with a significantly greater increase in fat free mass and a decrease in fat mass compared with placebo. RT combined with whey protein also had a positive impact on body composition, but the respective effects were more pronounced following the specific collagen peptide administration.

Pain-guided activity modification during treatment for patellar tendinopathy: a feasibility and pilot randomized clinical trial

BACKGROUND

Activity modification is a key component of patellar tendinopathy treatment but there is a lack of evidence guiding activity modification prescription. Use of activity modification in treatment studies has varied widely and the impact of those recommendations has not been directly investigated or compared. The purpose of this study was to assess (1) the feasibility of using pain-guided activity modification during treatment for patellar tendinopathy and (2) if our outcome measures are responsive to changes in tendon health over the course of treatment.

METHODS

This was an unblinded, randomized two-arm pilot and feasibility study randomized clinical trial with parallel assignment, conducted in Newark, DE. Individuals between the ages of 16 and 40 years old with patellar tendinopathy were included. Participants were randomly assigned to a pain-guided activity (PGA) or pain-free activity (PFA) group using a spreadsheet-based randomization scheme. All participants received standardized treatment using a modified version of the heavy-slow resistance protocol 3×/week for 12 weeks. For the first 6 weeks, the PGA group used the Pain-Monitoring Model to guide activity outside of treatment and the PFA group was restricted from running, jumping, or activities that provoked their patellar tendon pain. Feasibility outcomes included recruitment, enrollment, randomization, compliance, and retention percentages. Clinical evaluations were conducted at baseline, 6, and 12 weeks to assess symptom severity, psychological factors, tendon morphology and mechanical properties, lower extremity function, and quadriceps muscle performance.

RESULTS

In a ~ 13-month period, 108 individuals were screened, 47/108 (43.5%) were eligible for participation, and 15/47 (32.0%) of those were enrolled (9 PGA, 6 PFA). The recruitment rate was 1.15 participants/month. The mean ± SD compliance with treatment was PGA: 86.1 ± 13.0% and PFA: 67.1 ± 30.7%. There was one missed evaluation session and two adverse events, which were not due to study interventions. Changes exceeding the smallest detectable change were observed for at least one outcome in each domain of tendon health.

CONCLUSIONS

Use of pain-guided activity modification during exercise therapy for patellar tendinopathy was found to be feasible, and the proposed outcome measures appropriate. Computer-based allocation concealment, blinding of evaluators, and greater recruitment of high-level athletes should be implemented in future trials.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03694730 . Registered 3rd of October, 2018.

The Influence of Specific Bioactive Collagen Peptides on Knee Joint Discomfort in Young Physically Active Adults: A Randomized Controlled Trial

First evidence indicates that the supplementation of specific collagen peptides is associated with a significant reduction in activity-related joint pain in young adults. The purpose of the current investigation was to confirm the efficacy of the same collagen peptides in a comparable study population. In total, 180 active men and women aged between 18 and 30 years with exercise-related knee pain but no diagnosed joint disease completed the trial over a period of 12 weeks. Participants were randomly assigned to the group receiving 5 g of specific collagen peptides (CP-G) or to the placebo group (P-G). For the primary outcome, changes in pain during or after exercise from pre- to post-intervention were assessed by the participants using the Visual Analog Scale (VAS). These changes were additionally evaluated by the examining physician by means of anamnesis and physical examination of the affected knee joint. As secondary outcomes, pain under resting conditions and after 20 squats were compared between the study groups. In addition, the mobility of the knee joint and the use of alternative therapies (e.g., ointments or physiotherapy) were recorded. The supplementation of specific collagen peptides derived from type I collagen with a mean molecular weight of 3 kDa led to a significantly (p = 0.024) higher reduction of exercise-induced knee pain (−21.9 ± 18.3 mm) compared with the placebo group (−15.6 ± 18.5 mm). These findings were consistent with the physician’s evaluation (−23.0 ± 19.2 mm vs. −14.6 ± 17.9 mm, p = 0.003). The decrease in pain under resting conditions and after squats did not significantly differ between the groups, as only a small number of participants suffered from pain under these conditions. Due to the clinically unremarkable baseline values, the mobility of the knee joint did not change significantly after the intervention. In conclusion, the current investigation confirmed that the oral intake of bioactive collagen peptides used in the current investigation led to a statistically significant reduction of activity-related joint pain in young active adults suffering from knee joint discomfort.

Influence of Specific Collagen Peptides and Concurrent Training on Cardiometabolic Parameters and Performance Indices in Women: A Randomized Controlled Trial

The purpose was to examine the effects of concurrent training (CT) combined with specific collagen peptides (SCP) intake on cardiometabolic parameters and performance indices in women. In a double-blind, placebo-controlled, randomized trial recreationally active women (n = 59) completed a 12-week CT training (3 day/week) and ingested 15 g of SCP (treatment group [TG]) or placebo (control group [CG]) on a daily basis. Running distance as a marker of endurance performance (time trial), velocity and heart rate at the lactate and anaerobic threshold (incremental running test) and body composition (bioelectrical impedance analysis [BIA]) were measured. BIA measurements included determination of fat mass (FM) and fat free mass (FFM). Additionally, muscular strength (one-repetition-maximum [1RM]) and muscular endurance (60% of 1RM) were assessed. After 12-weeks, TG had a higher increase in running distance (1,034 ± 643 m) compared to the CG (703 ± 356 m) indicated by a significant interaction effect (p < 0.05). Velocity at lactate and anaerobic threshold improved in both groups over time (p < 0.001), with no significant differences between groups. Similarly, heart rate at lactate threshold decreased over time (p < 0.001), with no time × group interaction. TG declined more in heart rate at anaerobic threshold (−8 ± 14 bpm) than the CG (−1 ± 7 bpm), which resulted in a significant interaction effect (p < 0.01). FM decreased over time in TG and CG (p < 0.001), with no group differences. On contrary, TG had a higher increase in FFM (0.8 ± 0.9 kg) compared to the CG (0.3 ± 1.0 kg) (time × group interaction: p < 0.05). Both, 1RM and muscular endurance improved over time (p < 0.001), with no significant group differences. In conclusion, supplementation of SCP in combination with CT resulted in a significant increase in endurance performance compared to the control group. This might potentially be a consequence of improved structural and cardiometabolic adaptations.

Probiotic Fermented Milk with Collagen

The aim of this study was to assess the possibility of using collagen protein hydrolysate in the production of milk fermented by Bifidobacterium animalis ssp. lactis Bb-12 and Lactobacillusrhamnosus. Physicochemical and organoleptic properties were studied and microbiological analysis of fermented milk was performed on days 1 and 21 of storage. Milk with the addition of 3% collagen protein hydrolysate was pasteurized (85 °C/30 min), divided into two groups, cooled to 37 °C and inoculated: the first group with Bifidobacteriumanimalis ssp. lactis Bb-12, second with Lactobacillus rhamnosus. Incubation was carried out at 37 °C/10 h. After 21 days of refrigerated storage, the pH value decreased in all analyzed milk samples. Collagen protein hydrolysate was a good milk additive to increase gel hardness and reduce syneresis. Moreover, its addition did not change the taste and odour of milk fermented with the use of Bifidobacterium Bb-12 and Lactobacillus rhamnosus. Collagen protein hydrolysate favourably stimulated the survival of Bifidobacterium Bb-12 during 21 days of storage. After 21 days of cold storage in milk with collagen, the number of Lactobacillus rhamnosus cells was reduced by 0.11 log cfu g−1.

Plasma Amino Acid Concentrations After the Ingestion of Dairy and Collagen Proteins, in Healthy Active Males

Introduction: Recent evidence suggests that the consumption of essential amino acids (AA) and/or those abundantly present in collagen may have the capacity to influence the synthesis of new collagen in ligaments and tendons, when tissue perfusion is optimized (e.g., during exercise). However, little is currently known about the bioavailability of these AAs in blood after the consumption of various collagen and diary protein sources: such information is needed to develop potentially useful dietary and supplement intake strategies. Objectives: The aim of the current study was to characterize blood AA concentrations in response to consumption of collagen and dairy protein sources; specifically, maximum concentrations, the timing of maximum concentration, and total (area under the curve) exposure above baseline. Methods: A 20 g serve of various dairy and collagen proteins, and a 300 mL serve of bone broth were consumed by healthy, recreationally active males after an overnight fast. Blood samples were drawn every 20 min for a total of 180 min, for analysis of plasma AA concentrations. Total AA, essential AA and collagen specific AAs were analyzed for maximum concentration, timing of peak, and area under the curve. Results: In general, protein intake was associated with a similar increase in total and collagen specific AAs, except for collagen proteins being a superior source of glycine (683 ± 166 μmol/L) compared to 260 ± 65 μmol/L for dairy proteins (P < 0.0001), whilst dairy proteins were a superior source of leucine (267 ± 77 μmol/L) compared to 189 ± μmol/L for collagen proteins (P < 0.04). Although there were several differences in the bioavailability of hydrolysed compared to non-hydrolysed proteins, this only reached statistical significance within the dairy proteins, but not for collagen proteins. Conclusions: The intake of collagen proteins result in higher plasma peaks of glycine, whilst the intake of dairy proteins result in higher plasma peaks of leucine. This information may support further investigations, and identification of key AAs that may support exercise in the synthesis of collagen.

Conservative Treatment of Chronic Achilles Tendinopathy: A Systematic Review

Achilles tendinopathy is a common musculoskeletal disorder. Athletes, runners and jumpers, and the sedentary are frequently affected. Numerous are the therapeutic choices to manage these kinds of disorders. The aim of this review is to analyze the available literature to document the up-to-date evidence on conservative management of Achilles tendinopathy. A systematic review of two medical electronic databases was performed by three independent authors, using the following inclusion criteria: conservative treatment consisted of pharmacologic, physical therapy without operative treatment, with more of 6 months symptoms and a minimum average of 6-months follow-up. Studies of any level of evidence, reporting clinical results, and dealing with Achilles tendinopathy and conservative treatment were searched for. A total of n = 1228 articles were found. At the end of the first screening, following the previously described selection criteria, we selected n = 94 articles eligible for full-text reading. Ultimately, after full-text reading and a reference list check, we selected n = 29 articles. Achilles tendinopathy is a frequent musculoskeletal disorder and several conservative treatments have been proposed, but no therapy is universally accepted, except for eccentric exercise training, which is the gold standard and a commonly used protocol.

Prolonged Collagen Peptide Supplementation and Resistance Exercise Training Affects Body Composition in Recreationally Active Men

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.

Significant Amounts of Functional Collagen Peptides Can Be Incorporated in the Diet While Maintaining Indispensable Amino Acid Balance

The results of twenty years of research indicate that the inclusion of collagen peptides in the diet can lead to various improvements in health. According to the current protein quality evaluation method PDCAAS (Protein Digestibility-corrected Amino Acid Score), collagen protein lacks one indispensable amino acid (tryptophan) and is therefore categorized as an incomplete protein source. Collagen protein displays a low indispensable amino acid profile, yet as a functional food, collagen is a source of physiologically active peptides and conditionally indispensable amino acids that have the potential to optimize health and address physiological needs posed by aging and exercise. The objective of this study was to determine the maximum level of dietary collagen peptides that can be incorporated in the Western pattern diet while maintaining its indispensable amino acid balance. Iterative PDCAAS calculations showed that a level as high as 36% of collagen peptides can be used as protein substitution in the daily diet while ensuring indispensable amino acid requirements are met. This study suggests that the effective amounts of functional collagen peptides (2.5 to 15 g per day) observed in the literature are below the maximum level of collagen that may be incorporated in the standard American diet.

Enzymatic Hydrolysis of a Collagen Hydrolysate Enhances Postprandial Absorption Rate-A Randomized Controlled Trial

Collagen is characterized by its high content of glycine, proline and hydroxyproline, and is found to exert beneficial effects on joint pain related to activity and osteoarthritis. However, to exert any beneficial effects it is essential that collagen is optimally absorbed. This study aimed to investigate the postprandial absorption of collagen and elucidate the impact of an exogenous enzymatic hydrolysis on absorption rate and bioavailability. A randomized, blinded, cross-over study was conducted where ten healthy male subjects received either 35 g enzymatically hydrolyzed collagen protein (EHC), 35 g non-enzymatically hydrolyzed collagen protein (NC) or placebo (250 mL water) on three nonconsecutive days. Blood samples were drawn before, and up to 240 min following, ingestion and the blood metabolome was characterized by nuclear magnetic resonance (NMR)-based metabolomics. A significant increase in the plasma concentration of nearly all amino acids (AAs) was observed over a 240 min period for both EHC and NC. In addition, the absorption rate and bioavailability of glycine, proline and hydroxyproline were significantly higher for EHC (p < 0.05). In conclusion, ingestion of collagen hydrolysates increases postprandial plasma concentrations of AAs over a period of 240 min, and an enzymatic hydrolysis increases the absorption rate and bioavailability of the collagen-rich AAs glycine, proline and hydroxyproline.