Whey and Soy Protein Supplementation in Football Players

Study Overview
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Brief Summary
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In a constant effort to find ways to make a quicker recovery between demanding workouts and football matches, this study is the first to investigate the benefits of protein supplementation, and compares two types of proteins, an animal-derived (whey) and a plant-derived (soy) protein, after an exercise-induced muscle injury caused by a speed endurance training protocol. Soy protein could be a cheaper and more environment-friendly alternative for athletes involved in high-velocity strength training.

Detailed Description
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A randomized, three-trial (placebo vs. whey protein isolate vs. soy protein isolate consumption), cross-over, double-blind design. Baseline performance testing: Initially, volunteers will participate in a performance testing procedure at University facilities. These measurements include: A) measurement of descriptor variables: a) body composition (DXA), b) VO2max, c) Yo-Yo intermittent endurance level 2 (Yo-Yo IE2), d) Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2), e) technical skill level, f) daily dietary intake profile (over a 7-day period), g) gabitual physical activity level (over a 7-day period) and h) resting mtabolic rate (RMR). B) Measurement of dependent variables: a) isokinetic strength (concentric, eccentric) and maximal voluntary isometric contraction (MVIC) of knee extensors and flexors of both lower limbs, b) counter movement jump height (CMJ), c) repeated sprint ability (RSA), d) speed (10 and 30 m), e) delayed onset of muscle soreness (DOMS), f) blood sampling for measurement of lactate concentration, creatine kinase activity (CK) and inflammatory markers [i.e.Glutathione (GSH), total antioxidant capacity (TAC) and protein carbonyls (PC)]. A 1-week adaptive period: based on a dietary analysis, participants will be given a dietary plan [taking into account the resting metabolic rate (RMR) and total daily physical activity related energy expenditure], providing a standard protein intake of 0.8-1 g protein/kg/day over the 1-week adaptive period. This protein intake is accepted as the average and population-safe protein intake during periods of very low physical activity and/or exercise levels. RMR, daily dietary intake and physical activity will be measured before the adaptive period. Familiarization with the training protocol will take place during this phase. Participants will randomly participate in three trials including: whey protein (WP), soy protein (SP) and placebo (PL) supplementation: A 7-day pre-loading phase: A 7-day pre-loading phase will be applied prior to each trial, during which volunteers will receive the respective supplement (placebo, whey protein or soy protein). In WP and SP trials, participants will consume daily the appropriate amount of protein to reach a total protein intake of 1.5 g protein/kg body weight (BW). On the 7th day (end of pre-loading phase), participants will repeat performance testing (assessment of all dependent variables according to baseline testing) and blood sampling. On the 8th day, participants will perform the speed-endurance production training (SEPT) session 1 (1st trial). During training, participants internal (heart rate) and external load (total distance, speed zones, acceleration and decelerations, impacts) will be continuously monitored using heart rate monitors and global positioning system (GPS) instrumentation. Immediately after the training protocol: Determination of blood lactate concentration (3-4 minutes post-training) and assessment of MVIC (1 hour, 2 hours and 3 hours post-training). 1-Day post-training (9th day; 24 hours post-training): Blood sampling (for the determination of CK, GSH, TAC and PC) and measurement of dependent variables (i.e. isokinetic strength, MVIC, Speed, RSA, CMJ and DOMS). 2-Days post-training (10th day; 48 hours post-training): Blood sampling (for the determination of CK, GSH, TAC and PC) and assessment of DOMS. Thereafter, the SEPT session 2 will take place during which the particpants' internal and external load will be continuously monitored (as described in SEPT session 1). Wash-out period: 2-week without any activity or supplementation. 2nd trial: repeat of stages 3 and 4. 3rd trial: repeat of stage 3.

Official Title
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Comparison of the Effect of Whey and Soy Protein Supplementation on Muscle Damage Markers and Performance After a Speed Endurance Training Protocol in Football Players

Conditions
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Skeletal Muscle Damage, Muscle Damage, Athletic Performance

Intervention / Treatment
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* Dietary Supplement: Whey protein
* Dietary Supplement: Soy protein
* Dietary Supplement: Placebo (maltodextrin)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Playing at a competitive level (top three divisions) for ≥3 years Free of any recent history of illnesses, musculoskeletal problems and metabolic diseases No use of supplements and medications (for ≤6 months prior to the study) Non-smokers Exclusion Criteria: A known milk intolerance or allergy A recent febrile illness History of muscle lesion Lower limb trauma Metabolic diseases.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 25 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Whey protein<br>Whey protein isolate supplementation (7 day pre-loading phase and 3 day training phase). The protein dose will be individually adjusted to reach a total protein intake of 1.5 g protein/kg body mass/day. | Dietary Supplement: Whey protein<br>* Whey protein isolate supplementation, individually adjusted to reach a total protein intake of 1.5 g/kg body weight/day for 10 days (7 days pre-loading and 3 days during trials 1 and 2)<br>|
| Experimental: Soy protein<br>Soy protein isolate supplementation (7 day pre-loading phase and 3 day training phase). The protein dose will be individually adjusted to reach a total protein intake of 1.5 g protein/kg body mass/day. | Dietary Supplement: Soy protein<br>* Soy protein isolate supplementation, individually adjusted to reach a total protein intake of 1.5 g/kg body weight/day for 10 days (7 days pre-loading and 3 days during trials 1 and 2)<br>|
| Placebo Comparator: Placebo (maltodextrin)<br>Isoenergetic, maltodextrin (7 day pre-loading phase and 3 day training phase) | Dietary Supplement: Placebo (maltodextrin)<br>* Isoenergetic placebo (maltodextrin) for 10 days (7 days pre-loading and 3 days during trials 1 and 2<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in field activity during the speed-endurance production training (SEPT) | Field activity will be continuously recorded during both SEPT sessions using global positioning system (GPS) technology | Throughout the SEPT sessions in all trials | 
| Change in heart rate during the speed-endurance production training (SEPT) | Heart rate will be continuously recorded during both SEPT sessions using heart rate monitors. | Throughout the SEPT sessions in all trials | 
| Change in creatine kinase in plasma | Concentration of creatine kinase will be measured in plasma | Baseline; Post-loading (Day 7); 24 hours (Day 9) and 48 hours (Day 10) following SEPT session 1. | 
| Change in repeated sprint ability (RSA) | 5 x 30 m sprints will be performed with 25 seconds rest in-between | Baseline; Post-loading (Day 7); 24 hours (Day 9) following SEPT session 1 | 
| Change in countermovement jump (jump height in centimeters) | Countermovement jump will be assessed on a contact platform | Baseline; Post-loading (Day 7); 24 hours (Day 9) following SEPT session 1 | 
| Change in isokinetic strength of lower limbs | Isokinetic strength will be assessed on an isokinetic dynamometer for both knee extensors and knee flexors at 60 degrees. | Baseline; Post-loading (Day 7); 24 hours (Day 9) following SEPT session 1 | 
| Change in maximal voluntary isometric contraction (MVIC) of lower limbs | MVIC will be assessed on an isokinetic dynamometer for knee extensors at 90 degrees and knee flexors at 30 degrees | Baseline; Post-loading (Day 7); 1, 2 and 3 hours post-SEPT session 1; 24 hours (Day 9) and 48 hours (Day 10) following SEPT session 1. | 
| Change in delayed onset of muscle soreness | Muscle soreness will assessed during palpation of the muscle belly and the distal region of relaxed vastus medialis, vastus lateralis and rectus femoris following three repetitions of of a full squat. Subjects will rate their DOMS on a visual analogue scale (0-10). A score of O indicates no sign or symptom of DOMS, a score of 10 indicated severe signs and symptoms of delayed onset muscle soreness (DOMS). These signs and symptoms include dull, diffuse pain and tenderness; stiffness; swelling; and decreased strength of the exercised muscle. | Baseline; Post-loading (Day 7); 24 hours (Day 9) and 48 hours (Day 10) following SEPT session 1. | 
| Change in total antioxidant capacity in plasma | Total antioxidant capacity will be measured in plasma | Baseline; Post-loading (Day 7); 24 hours (Day 9) and 48 hours (Day 10) following SEPT session 1. | 
| Change in protein carbonyl levels in plasma | Protein carbonyl levels will be measured in plasma | Baseline; Post-loading (Day 7); 24 hours (Day 9) and 48 hours (Day 10) following SEPT session 1. | 
| Change in GSH levels in red blood cell lysate | GSH will be measured in red blood cell lysate | Baseline; Post-loading (Day 7); 24 hours (Day 9) and 48 hours (Day 10) following SEPT session 1. | 
| Change in sprint time | Sprint time will be assessed over a 10m and 30m distance using light cells. | Baseline; Post-loading (Day 7); 24 hours (Day 9) following SEPT session 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dietary intake | Dietary intake will be assessed using 7-day diet recalls. | Over a 7-day period at baseline. | 
| Concentration of blood lactate | Blood lactate will be measured using an automatic analyzer | Pre- and Post-SEPT session 1 (Day 8), Pre- and Post-SEPT session 2 (Day 10) | 
| Change in habitual physical activity | Physical activity will be measured using 3-axial accelerometers | Over a 7-day period at baseline | 
| Change in resting metabolic rate (RMR) | RMR will be measured using open-circuit indirect calorimeter with a ventilated hood system, after an overnight fast. | At baseline. | 
| Change in body composition | Body composition will be assessed using dual-energy X-ray absorptiometry (DXA). | At baseline. | 
| Change in maximal oxygen uptake | Maximal oxygen uptake (VO2max) will be measured during a graded exercise testing on a treadmill, by using open-circuit spirometry with an automated online pulmonary gas exchange system, via breath-by-breath analysis. | At baseline. | 
| Change in soccer-specific conditioning. | Soccer-specific conditioning will be assessed using the the Yo-Yo intermittent endurance level 2 test (Yo-Yo IE2) and the Yo-Yo intermittent recovery level 2 test (Yo-Yo IR2). | At baseline. |