Effects of 16 weeks of two different high-protein diets with either resistance or concurrent training on body composition, muscular strength and performance, and markers of liver and kidney function in resistance-trained males

ABSTRACT

Purpose

It is unclear whether resistance (RT) and concurrent training (CT; resistance plus endurance training) combined with different protein intakes have differential effects on muscle hypertrophy, strength, and performance. Therefore, we compared the effects of two high-protein diets (1.6 or 3.2 g.kg^−1.d⁻¹) during 16 weeks of either CT or RT alone in resistance-trained males.

Methods

Forty-eight resistance-trained males (age: 26 ± 6 yr, body mass index: 25.6 ± 2.9 kg.m⁻²) performed 16 weeks (four sessions·w⁻¹) of CT or RT with either 1.6 g.kg^−1.d⁻¹ protein (CT1; n = 12; RT1; n = 12) or 3.2 g.kg^−1.d⁻¹ protein (CT2; n = 12; RT2; n = 12). Training adaptations were assessed pre-, mid-, and post-intervention.

Results

All measures of performance (endurance, vertical jump, and pull-up), lean mass, muscle strength, and power significantly increased post-intervention in all groups, but peak power gains were greater in RT2 compared with RT1 and CT1 (p < .05). VO_2max significantly increased in both CT groups (p < .001). Select biochemical markers of kidney and liver function significantly increased within the RT2 and CT2 groups (p < .05), however, no between-group differences were apparent (p > .05).

Conclusions

With the exception of peak power, intake of 1.6 g.kg^−1.d⁻¹ of protein appears sufficient to maximize gains in lean mass, muscle strength, performance, and aerobic capacity during both RT and CT without influencing markers of kidney and liver function, indicating this daily protein amount is effective and safely tolerated in young, healthy adults.

KEYWORDS:

• Concurrent exercise
• protein intake
• skeletal muscle adaptation
• exercise performance

Acknowledgments

We would like to express our great appreciation to Dr. Neda Cheraghloo for her valuable and constructive suggestions during data analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ information

This was provided on the first page.

Ethical approval and consent to participate

The protocol was reviewed by the Institutional Human Subject Committee and the Ethics Committee of the University of Isfahan (IR.UI.REC.1400.098) and carried out in accordance with the Declaration of Helsinki. This study has been registered with the Iranian Registry of Clinical Trials (IRCT20191204045612N2). All participants signed an informed consent form and were informed that they could withdraw from the study at any point.

Consent for publication

We agree to publications after acceptance in JISSN.

Datat availability statement Data sharing is applicable.

Authorship contributions

Conceptualization: [Reza Bagheri and Donny M Camera]; Methodology: [Reza Bagheri, Donny M Camera, David Scott, Ramin Sadeghi, and Mehdi Kargarfard]; Formal analysis and investigation: [Reza Bagheri]; Writing – original draft preparation: [Reza Bagheri and Donny M Camera]; Writing – review and editing: [Reza Bagheri, Donny M Camera, David Scott, and Ramin Sadeghi]; Supervision: [Mehdi Kargarfard].

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15502783.2023.2236053

Additional information

Funding

The University of Isfahan provided funding sources to perform study procedures.