The purpose of this study is to determine the effects of repeated dosing vitamin C enriched hydrolyzed collagen (HC) over a 24hr period, compared to PrimaColl™ (PC), whey protein (WP) and placebo (PL), with prescribed exercise on collagen synthesis.

To achieve this, participants will consume a supplemental dose of HC (20g with 50mg vitamin C), PC (20g with 50mg vitamin C), whey protein (20g whey isolate with 50mg vitamin C) or a placebo (20g maltodextrin with 50mg vitamin C) 1hr prior to an exercise bout (6 minutes of jump rope), this will be repeated three times over a 24h period.

The amount of collagen protein synthesized will be indirectly measured by measuring pro-collagen type I N-terminal propeptide (PINP) in the serum before and 4hrs after the last exercise bout.

The purpose of this study is to determine the effects of repeated dosing of vitamin C enriched hydrolyzed collagen (HC) over a 24hr period, compared to PrimaColl™ (PC), whey protein (WP) and placebo (PL), with prescribed exercise on collagen synthesis.

To achieve this, participants will consume a supplemental dose of HC (20g with 50mg vitamin C), PC (20g with 50mg vitamin C), whey protein (20g whey isolate with 50mg vitamin C) or a placebo (20g maltodextrin with 50mg vitamin C) 1hr prior to exercise bouts (6 minutes of jump rope). The amount of collagen protein synthesized will be indirectly measured by measuring procollagen type I N-terminal propeptide (PINP) in the serum before and 4hrs after the last exercise bout.

It is expected that this project will determine whether greater increases in collagen synthesis are observed with repeated doses of HC and exercise, compared with a single dose and exercise bout (from previous research). This study will also determine whether collagen synthesis is similarly stimulated with PrimaColl, or whey protein. Results from this study will help to better prescribe the use of dietary collagen and exercise training to improve collagen synthesis in healthy young people. Improved collagen synthesis has the potential to decrease ligament, tendon, and bone injuries in the general and athletic populations.

Male and female participants between the ages of 18-30 years of age will be enrolled in the study. A randomized double-blind crossover design with neither the subjects nor the investigators knowing who is on which treatment (HC, PC, WP or PL).

I. Baseline blood draw

The subjects will arrive in the laboratory following an overnight fast. The antecubital vein will be cannulated, and an initial 5 mL baseline blood sample will be collected.

II. Supplementation

After baseline blood draw subjects will be provided with a supplement as shown in the table below. Subjects will be asked to consume the supplement that will be pre-mixed with 250 ml of water 60 min before the jump rope exercise. This will be repeated 3 times, separated by 12 hours over a 24h period.

III. Exercise

Sixty minutes after the ingestion of the supplement, each participant will complete 6 minutes of jump rope. This will be repeated on 3 occasions over a 24hr period. Subjects will be asked to abstain from vigorous exercise during the 24hr period, aside from the prescribed jump rope exercise.

Subjects will be asked to ingest supplement and jump rope in lab for time point 1. Subjects will be given the option to ingest supplement and jump rope outside lab if more conducive to their scheduling restrictions at time points 2 and 3 blood draws are not required at these timepoints. Subjects will be asked to return to the lab 4 hours after last jumping session for blood sampling.

Blood draws for PNIP analysis

Blood samples (5 mL) at different time points:

• Baseline 2 vials will be drawn (1 for PINP and the other for bioassays)
• 1h after the first supplementation 1 vial will be drawn (bioassay)
• 4hrs post-exercise session number 3 the last vial will be drawn (PINP) Blood will be collected in 5 mL serum separating tubes and allowed to clot for 1hr before centrifugation at 1000 x g for 10 minutes and the serum will be frozen and kept at -30°C until processed. PINP levels will be determined by electrochemiluminescence (ECL; Roche Diagnostics, Indianapolis, IN) according to the manufacturer's instructions. The total number of blood draws will be 12 (3 per intervention with 4 interventions). Treatments will be randomized to avoid an order effect and a washout period of about 72h between trials will be used to minimize the effect of the previous treatment

Inclusion Criteria:

• healthy active male or female
• normal weight (BMI between 18 and 25 kg/m2)

Exclusion Criteria:

• taking any medication that may interfere with the study
• have a history of more than 3 musculoskeletal injuries within the past 12 months
• have any health or dietary restriction that would be affected by the supplementation protocol

A randomized double-blind crossover design with neither the subjects nor the investigators knowing who is on which treatment. The interventions will be coded using a blinded alphabetical letter code (A, B, C, D). A delegate researcher (independent party not further involved in the study) will randomize all interventions using a computer-generated randomization list. The delegate will hand in the code-breaker to the principal investigator in a sealed envelope. The envelope will be stored in a locked filing cabinet in the principal investigator's office, which will also be locked when unoccupied. The envelope will be opened by the principal investigator after completing the analysis of blood samples.