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D1 Featured In Men's Journal On How Endurance Workouts Build Muscle, Mental Toughness

Nov 21, 2025 / Author: Clif Marshall
D1 Training, Clif Marshall, Men's Journal

Clif Marshall is D1 Training's Senior Director of Coaching and Pro Training. Each week in D1 Daily, Clif shares his insight gained from more than 20 years working in strength and conditioning.

Editor’s Note: Clif recently had the opportunity to contribute to a Men’s Journal article about a military style endurance workout. What follows is a Q&A that Clif submitted to the publication’s editors. To read the full article and workout, go here.

Strength Under Stress

A full-body workout is a game-changer because it targets multiple muscle groups simultaneously, unlike traditional strength sessions that isolate specific muscle groups. This approach builds overall stability and stamina. To push yourself safely, it's crucial to focus on proper form first and then gradually increase the resistance. Remember, the moment your form starts to break down, it's time to stop and reset. Think quality over quantity!  

Combat Conditioning 

This workout is all about combining bursts of cardio with powerful strength moves. The key is to remain explosive while keeping control. A common mistake people make is going too fast and sacrificing good form. Always remember, pacing yourself is essential. 

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Tactical Agility

Speed and coordination often get overlooked because most people focus more on strength or cardio. This workout is designed to make both your body and brain work together, incorporating quick direction changes, reaction drills, and balance exercises. It trains the "athlete mindset," not just the muscles. I call it “cognitive athleticism”! 

Endurance Under Pressure

This workout is as much about mental resilience as it is about physical fitness. When fatigue sets in, I advise athletes to control their breathing, reset their posture, and tackle one rep at a time. This method builds mental toughness safely through structured practice and self-awareness.

Go here to read the full article in Men’s Journal featuring D1 coach Clif Marshall

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