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Trial registered on ANZCTR


Registration number
ACTRN12617001229369
Ethics application status
Approved
Date submitted
28/07/2017
Date registered
23/08/2017
Date last updated
23/08/2017
Type of registration
Retrospectively registered

Titles & IDs
Public title
Effect of concurrent resistance and endurance exercise on muscle growth in healthy men.
Scientific title
Effect of concurrent resistance and endurance exercise on muscle growth in healthy men.
Secondary ID [1] 292475 0
None
Universal Trial Number (UTN)
Trial acronym
CSCS
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Muscle hypertrophy 304098 0
Condition category
Condition code
Musculoskeletal 303433 303433 0 0
Normal musculoskeletal and cartilage development and function

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The study will employ a, parallel-groups design incorporating diet and exercise manipulation. Following appropriate preliminary testing, subjects will be assigned to one of three experimental groups: Resistance Exercise Only and High Protein Diet (Group 1), Endurance Exercise Only and High Protein Diet (Group 2), or Concurrent Resistance and Endurance Exercise and High Protein Diet (Group 3). Skeletal muscle biopsies will be obtained at rest (i.e.: 2 weeks before intervention commencement), 3 days following the first exercise session, after 4 weeks of training, after 8 weeks of training, and three days after the 12-wk training and nutrition intervention. There is no placebo group as the main purpose of this study is to determine whether nutritional strategies such as increased protein ingestion through a ‘high protein diet’ can offset declines in muscle strength and hypertrophy with chronic (i.e.: 12 weeks) concurrent training.

Body Composition and Urine Sample:
A dual energy X-ray absorptiometry scan (DXA) is a specialised X-ray technique to provide a measure of body composition. This is just like a normal X-ray, with no pain involved and it will measure total body mass, fat mass and lean mass. Participants will be scanned wearing light clothing at the beginning, 4 weeks, 8 weeks and conclusion of the study.

Ultrasound
Two-dimensional ultrasound is the most common technique used for assessing the structure of a muscle. Two-dimensional ultrasound will then be used to assess the structure of the quadriceps muscles at three sites along the length of the thigh. Participants will then have the structure of their hamstring muscles assessed.

Strength and Power Testing
Maximum muscular strength will be determined during a series of one repetition maximum (1RM) attempts and during an isometric mid-thigh pull (IMTP). The 1RM attempts will be performed on the leg press, leg extension, and bench press exercises. 1RM values from this test will be used to prescribe individualized training ranges/intensity..The IMTP is a simple test performed on a force platform that assesses lower-body strength. Participants will be shown correct and safe technique for each exercise by a qualified exercise physiologist and will subsequently be provided with appropriate time to safely perform each technique until competent and comfortable.

To assess power output, participants will perform two different jumps on the force platform: a countermovement jump (CMJ) and a squat jump (SJ). During the CMJ, participants will place their hands on their hips and try to jump as high as they can. As per the strength testing, participants will receive adequate instruction and demonstration prior to completing the testing.

VO2Peak Test
The VO2peak test is an incremental test to exhaustion on a stationary cycle ergometer. The workload increases every 2½ minutes until you can no longer maintain a pedalling rate of 60-70 rpm. This test is expected to last between 10-15 minutes. During the test expired air will be sampled as participant breathe into a mouthpiece attached to an automated gas analyser. The results from this test will provide a peak oxygen consumption reading and peak power output (PPO) and physiological data regarding cardiovascular health and fitness. PPO from this test will be used to prescribe individualized training ranges/intensity.

Dietary Intervention
For the duration of the 12-week exercise and nutrition intervention, participants will consume a ‘high’ protein diet. A diet is considering high in protein if it consumed above the recommended daily intake of 0.8g/kg/day. In this study, daily protein intake will be set at 2 g/kg/day, with a recommended total daily energy intake of 30 – 40 kcal/kg/day. This level of protein consumption is completely safe with similar, and in many cases, higher quantities used within the research field. Individual diet counselling as well as personal food and recipe plans will be provided face-to-face and via phone (based on availability) by the study dietitian on a fortnightly basis throughout the entire study. These appointments will typically range from 30-60 minutes. Participants will log their food intake using the Easy Diet Diary™ mobile phone App or manually through a ‘food diary’.

Exercise Training Program
All training sessions will be held in the exercise physiology labs/gyms located at ACU under direct supervision of Mr. Shamim and Dr. Camera. Mr. Shamim has extensive experience with intercollegiate strength and conditioning, powerlifting, and holds a Master's of Research degree in Sport and Exercise Sciences. Dr. Camera is a qualified personal training and holds a doctorates in Exercise Science. Sessions will be delivered in a group setting and last approximately 60 minutes each.

Group 1: Resistance Exercise Only with High Protein Diet
Participants in Group 1 will consume a ‘high protein’ diet as described above and perform only resistance exercise three times per week for the duration of the 12-wk training period. Resistance exercise will progressively increase in weight to account for increases in muscle size and strength throughout the program.
The resistance exercise protocol will consist of a whole-body routine including the following types of exercises: chest press, lat pulldown, rows, leg extension, leg press, shoulder press and lunges.
1) Phase 1 – Familiarization (Week 1): Sessions in this period will introduce main movements and exercises (~60-65% 1RM).
2) Phase 2 – Hypertrophy (Weeks 2-6): Sessions in this period will focus primarily on building muscle mass through higher volume of repetitions per session. Load will increase in a linear progression throughout this phase (~65-80% 1RM).
3) Phase 3 – Power (Week 7): Sessions in this phase of training will act as a ‘de-loading’ period and aim to improve muscle power in primary movements (~60-70% 1RM)
4) Phase 4 – Strength (Weeks 8-10): Sessions in this phase will focus on strength development and consist of a lower volume of repetitions paired with heavier weights. A linear increase in load will also be used during this phase (~80-90% `1RM)
5) Phase 5 – Peaking (Weeks 11-12): Sessions in this phase will focus solely on peaking the neuromuscular system and preparing for the main movements performed during the final strength testing. (~90-95% 1RM)

Participants in the resistance exercise group will be required to training on three occasions per week (Monday, Wednesday, and Friday OR Tuesday, Thursday, and Saturday).

Group 2: Endurance Exercise Only with High Protein Diet
Participants in Group 2 will consume a ‘high protein’ diet as described above and perform only endurance-based exercise on a stationary exercise bike three times per week for the duration of the 12-wk training period.

Endurance exercise will consist of variety of diverse exercise sessions including:
• 30-45 minutes of moderate intensity cycling on a stationary ergometer at approximately 50-75% of VO2peak capacity at a speed of approximately 60-70 rpm
• 30-45 minutes of high-intensity interval training involving 5 mins of cycling at approximately 75-85% of each individual’s pre-determined VO2peak capacity with 60 seconds of recovery period.
• 30-45 minutes of Sprint interval training involving <60 seconds of cycling at approximately 85-100% of each individual’s pre-determined VO2peak capacity with varying recovery periods of 30 seconds, 40 seconds, 1 minute, or 4 minutes based on session.

Participants in the endurance exercise group will be required to training on three occasions per week (Monday, Wednesday, and Friday OR Tuesday, Thursday, and Saturday).

Group 3: Combined Resistance and Endurance Exercise with High Protein Diet
Participants in Group 3 will consume a ‘high protein’ diet as described above and will perform combined resistance and endurance exercise six times per week for the duration of the 12-week training period. The concurrent training program will incorporate the same resistance and endurance exercise protocols mentioned in Group 1 and Group 2, respectively, on alternate days. Therefore participants in this combined exercise group will be required to perform resistance training on Monday, Wednesday, and Friday, and endurance training on Tuesday, Thursday, and Saturday, each week.

Muscle Tissue Biopsy
Muscle tissue biopsies will be collected on four occasions (Figure 1) during the study:
(1) Before the commencement of the 12-week training program (Week -2)
(2) 3 days after the completion of the 2nd week of exercise training (Week 3);
(3) 3 days after the completion of the 8th week of exercise training (Week 9); and
(3) 3 days after the completion of the 12-wk training program (Week 13).

Muscle biopsies are necessary in order to measure muscle growth responses to the respective diet and exercise interventions. The muscle biopsy procedure will be conducted by our study doctor who possesses extensive experience in the technique. The muscle biopsy sample is obtained from the outer thigh as this muscle site contains few surface sensory nerves. In preparation for a biopsy, a small amount of local anesthetic is injected under the skin which may result in a mild burning sensation while the fluid is injected. A small, 4-5 mm incision will then be made into your skin to create an opening for the biopsy needle. There is often a small amount of bleeding from the incision; however this bleeding is generally minimal. The biopsy needle will then be inserted through the incision site. There may also be some minimal bleeding when the needle is removed which may require the application of pressure for a few minutes. At the completion of each biopsy, the incision will be closed with sterile tape and wrapped with a bandage. Participants are advised to refrain from excessive muscle use for the remainder of the day.
Intervention code [1] 298659 0
Treatment: Other
Comparator / control treatment
The endurance only and resistance only groups will act as comparators to the combined exercise group.
Control group
Active

Outcomes
Primary outcome [1] 302817 0
To determine whether a high protein diet can ‘rescue’ the loss of muscle growth following 12 weeks of combined resistance and endurance exercise compared to resistance exercise only. Muscle growth will be assessed through skeletal muscle cross sectional area from biopsy samples, as well as DEXA and Ultrasound scans.
Timepoint [1] 302817 0
Pre intervention, post 2, 4, 6, and 8 weeks of training as well as post completion of the 12-week intervention, with the primary endpoint being post completion of the 12-week intervention.
Secondary outcome [1] 337136 0
Characterize the effects of 12 weeks of combined resistance and resistance and endurance exercise on strength compared to resistance or endurance exercise performed in isolation. Strength will be assessed through 1 repetition maximum testing of the leg press, leg extension, and bench press exercises, as well as maximal force output during the isometric mid-thigh pull movement performed on a digital force measurement platform.
Timepoint [1] 337136 0
Pre intervention, post 6-weeks of training, and post completion of the 12 week intervention.
Secondary outcome [2] 337914 0
Characterize the effects of 12 weeks of combined resistance and resistance and endurance exercise on muscle power compared to resistance or endurance exercise performed in isolation. Power will be assessed through the squat jump and counter movement jump performed on a digital force measurement platform.
Timepoint [2] 337914 0
Pre intervention and post completion of the 12 week intervention.

Eligibility
Key inclusion criteria
Healthy men, aged 18-35 years, with a Body Mass Index (BMI) of 18.5-29, and are recreationally active (defined here 2-3 days per week of non-structured/non-competitive exercise)
Minimum age
18 Years
Maximum age
35 Years
Gender
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
Smoking, steroid/anabolic agent use, vegan diets.

Study design
Purpose of the study
Treatment
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Stratified allocation employed in the study based on participant body masses such that each condition contains an equal distribution of body mass. Allocation of participants was done manually by random selection by a member of the research team blinded to all participant information except body mass.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Participant recruitment numbers (30 total; 10 per group) are based upon a priori power calculations using the methods of Hopkins (http://www.sportsci.org/resource/stats/). A minimum number of 12 participants per group (with allowance for a possible 15% dropout rate) will be required to detect a difference in each group (power = 80%, a = 0.05). A two-way with repeated measures analysis of variance (ANOVA) for Time (Pre to Post intervention) and Treatment (Group 1 vs. Group 2 vs. Group 3) and Student-Newman-Keuls post hoc test will be used during data analysis.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 297047 0
University
Name [1] 297047 0
Australian Catholic University (ACU)
Address [1] 297047 0
115 Victoria Parade, Fitzroy, VIC, 3065
Country [1] 297047 0
Australia
Primary sponsor type
University
Name
ACU
Address
115 Victoria Parade, Fitzroy, VIC, 3065
Country
Australia
Secondary sponsor category [1] 296050 0
None
Name [1] 296050 0
Address [1] 296050 0
Country [1] 296050 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 298228 0
ACU Human Research Ethics Committee
Ethics committee address [1] 298228 0
8-20 Napier Street-Level 16 (532.16)
North Sydney NSW 2059
Ethics committee country [1] 298228 0
Australia
Date submitted for ethics approval [1] 298228 0
16/02/2016
Approval date [1] 298228 0
21/05/2016
Ethics approval number [1] 298228 0
2016-54H

Summary
Brief summary
Exercise is well known to induce multiple physical and psychological benefits, although the nature of these benefits is dependent on the type of exercise performed. For instance, resistance training can increase muscle strength and mass, while endurance exercise can enhance the ability and efficiency to use energy so that exercise can be performed at higher intensities or longer durations.

Many individuals who undertake exercise, particularly those involved in team sports, perform a combination of resistance and endurance exercise so that all the physical benefits of exercise can be attained. However, previous research has established that the gains in muscle strength and mass with resistance exercise can be reduced when resistance exercise is performed concurrently with endurance exercise. The mechanisms responsible for this reduced response are not completely understood, but may be related to a combination of factors including fatigue, inadequate exercise intensity and/ or duration, and poor diet to facilitate muscle growth. In this regard, it is well established that protein ingestion can enhance muscle growth responses with resistance exercise. Whether protein can similarly enhance muscle growth following combined resistance and endurance exercise is not known. Accordingly, the aims of this research project are to:

1. Determine whether a high protein diet can ‘rescue’ the loss of muscle growth following 12 weeks of combined resistance and endurance exercise compared to resistance exercise only.
2. Characterise the effects of 12 weeks of combined resistance and resistance and endurance exercise on several performance tests measuring strength and power, and compare these responses to resistance or endurance exercise performed in isolation.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 76406 0
Dr Donny Camera
Address 76406 0
The Mary MacKillop Institute for Health Research
215 Spring Street
Level 5
Melbourne, VIC, 3000
Country 76406 0
Australia
Phone 76406 0
+61403166127
Fax 76406 0
Email 76406 0
donny.camera@acu.edu.au
Contact person for public queries
Name 76407 0
Mr Baubak Shamim
Address 76407 0
The Mary MacKillop Institute for Health Research
215 Spring Street
Level 5
Melbourne, VIC, 3000
Country 76407 0
Australia
Phone 76407 0
+61432703424
Fax 76407 0
Email 76407 0
baubak.shamim@myacu.edu.au
Contact person for scientific queries
Name 76408 0
Dr Donny Camera
Address 76408 0
The Mary MacKillop Institute for Health Research
215 Spring Street
Level 5
Melbourne, VIC, 3000
Country 76408 0
Australia
Phone 76408 0
+61403166127
Fax 76408 0
Email 76408 0
donny.camera@acu.edu.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary