Resistance Training and Hydrolyzed Collagen Supplementation in Middle-aged Adults

The aim of this clinical trial is to investigate the longitudinal effects of hydrolyzed collagen ingestion combined with resistance training on muscle-tendon unit structure and function in middle-aged males and females.

The main research questions this clinical trial aims to answer are:

1. Does resistance training with hydrolyzed collagen ingestion lead to greater changes in tendon properties than resistance training alone in middle-aged health men and women?
2. Does resistance training with hydrolyzed collagen ingestion lead to greater changes in muscle size than resistance training alone?
3. Does resistance training with hydrolyzed collagen lead to greater increases in strength and power compared to resistance training alone in middle-aged, healthy men and women?

Participants will be randomly assigned to collagen or placebo groups. Participants will perform 24 sessions of high intensity resistance training across 12-weeks. Alongside each training session, participants will consume a beverage containing hydrolyzed collagen or maltodextrin, with both beverages containing vitamin C.

Researchers will compare the collagen and placebo groups to see if there would be beneficial effects on changes in muscle and tendon that are greater than resistance training alone. To achieve this, an dynamometry will be used to assess lower limb strength and ultrasound will be used to measure the morphological, mechanical, and material properties of the patellar tendon, as well the size and architecture of the vastus lateralis muscle.

Healthy, active, middle-aged men and women will ingest a beverage containing 30 g of hydrolyzed collagen with 50 mg of vitamin C or a calorie matched beverage (maltodextrin), also with 50 mg of vitamin C combined with high-volume, high-intensity resistance training for the lower body on 2 - 3 occasions per week for 8-12 weeks.

The aim of this study was to investigate the effect of combining hydrolyzed collagen with resistance training in middle-aged men and women.If supplementation with hydrolyzed collagen leads to a greater change in tendon size, stiffness, and Young's modulus than resistance training alone, this will allow us to recommend this type of intervention to young athletes seeking to improve tendon health and/or athletic performance. This is the first study to investigate the combination of hydrolyzed collage supplementation with resistance training in middle-aged men and women. If supplementation with hydrolyzed leads to greater improvements in tendon size, stiffness, strength and/or power, this will allow us to recommend this type of intervention to middle-aged athletes/trainees seeking to improve tendon health, reduce injury risk, or enhance athletic performance.

The experimental design of both arms will be the same, however Arm 1 will be health, middle-aged male participants and Arm 2 will be health, middle-aged female participants.

Eligibility Criteria:
Inclusion Criteria:

* Recreationally active or competing in Masters sport
* No history of patellar tendon injuries in the past 6 months
* No history of lower limb musculoskeletal injuries in the past 6 months
* Non-smokers (including e-cigarettes)
* Free from cardiovascular and metabolic diseases

Exclusion Criteria:

* Age \< 35 years or \> 59 years
* Being vegan or vegetarian (due to the mammalian source of collagen)
* Injury history incompatible with lower body resistance training
* Consumption of nutritional supplementation that purportedly affects muscle-tendon adaptation or recovery (i.e. protein powder, vitamin C, collagen)
* BMI over 30 kg/m2