# Global Proteomics Reveals Distinct Muscle Adaptations to Menstrual Cycle Phase-Based Sprint Interval Training in Endurance-Trained Females

## TL;DR

This study shows that sprint interval training during different phases of the menstrual cycle leads to distinct muscle protein changes in trained women.

## Contribution

First global proteomic analysis of menstrual cycle phase-based sprint interval training in endurance-trained females.

## Key findings

- Luteal phase-based training suppressed mitochondrial pathways and reduced cardiorespiratory fitness.
- Follicular phase-based training preserved mitochondrial function and enhanced tissue remodeling.
- Phase-based training programming may optimize outcomes in well-trained females.

## Abstract

Advances in mass-spectrometry (MS)-based technologies have leveraged our understanding of protein-wide adaptations in human skeletal muscle in response to exercise. However, there is a lack of such data in females, particularly pertaining to already trained females and menstrual cycle phase-based sprint interval training (SIT) despite its efficacy and popularity. Here, we present a comprehensive global proteome analysis of skeletal muscle adaptations to high-frequency SIT during different menstrual cycle phases in endurance-trained females. We randomized 49 eumenorrheic females to either high-frequency SIT in the follicular (FB) or luteal phase (LB) over one menstrual cycle comprising eight sessions of 6 × 30-s all-out efforts. MS-proteomics, covering 4155 proteins after filtering, revealed notable differences in muscle adaptations to phase-based SIT. LB suppressed mitochondrial pathways of the tricarboxylic acid cycle and electron transport chain while enriching ribosomal complexes. Conversely, FB enriched filament organization and skeletal system development. Mitochondrial repression during LB was linked to reduced V˙ O2max, whereas exercise capacity improved in FB only. Our findings show that menstrual cycle phase-based high-frequency SIT induces distinct protein-wide muscle adaptations and affects phenotype in endurance-trained eumenorrheic females. NCT04136457.

•First to assess the global muscle proteome in females across menstrual phases.•MS-proteomics reveals phase-specific muscle adaptations to sprint interval training.•Luteal phase-based sprint interval training suppresses mitochondrial pathways.•Follicular phase-based sprint interval training enhances filament organization.•Phase-based programming may optimize training outcomes in well-trained females.

First to assess the global muscle proteome in females across menstrual phases.

MS-proteomics reveals phase-specific muscle adaptations to sprint interval training.

Luteal phase-based sprint interval training suppresses mitochondrial pathways.

Follicular phase-based sprint interval training enhances filament organization.

Phase-based programming may optimize training outcomes in well-trained females.

This study provides the first comprehensive proteomic analysis of menstrual cycle phase-based sprint interval training (SIT) in endurance-trained females. High-frequency SIT during the follicular phase preserved mitochondrial function and enhanced tissue remodeling, while luteal phase-based training suppressed mitochondrial pathways and reduced cardiorespiratory fitness. These findings emphasize the importance of considering menstrual cycle phase in female training strategies.