Remote Concurrent Training for Metabolic Fitness

A 16-week study on remote fitness training found that giving trainees the flexibility to choose their daily workout based on how they felt delivered the same strength and endurance results as following a rigid, prescribed schedule. The critical catch? People in the flexible group were more likely to skip sessions over time.

Published in the *International Journal of Exercise Science* by researchers from Liberty University and the University of Montevallo, this research tackles a practical question for anyone training outside a gym: is a flexible program as effective as a traditional one?

A Study of Fixed Schedules vs. Personal Choice

Christopher Bonilla and colleagues recruited 18 recreationally trained adults and split them into two groups. Both groups were given workouts to complete remotely over a four-month period.

One group, the control, received a fixed concurrent training program. Their schedule dictated which days were for strength (deadlifts, push-ups) and which for endurance (running), regardless of their daily readiness. The experimental group received the same library of exercises but was allowed to choose their workout each day based on their perceived energy and recovery levels. This “flexible” model aimed to mimic how many people naturally approach training when life—or fatigue—intervenes.

All participants were tested at the start and finish on three key metrics: maximal deadlift, maximum push-ups to failure, and time for a two-mile run. The primary goal was to see if the self-directed approach could match the proven results of a fixed plan.

Equal Fitness Gains, But a Decline in Adherence

The results on performance were clear. Both groups made significant and statistically similar improvements across all tests. Whether following a strict schedule or picking daily workouts, participants got stronger and improved their running. This finding confirms that for recreationally trained individuals, a flexible program is not a compromise; it’s a viable alternative that yields equivalent physical outcomes.

However, the data revealed a telling divergence in behavior. While both groups started with high compliance, adherence rates in the flexible-choice group dropped notably as the 16 weeks progressed. The researchers point to “decision fatigue” as a likely culprit. The constant need to decide *what* to do, rather than simply following instructions, may have become a mental burden, leading to more skipped sessions.

“The findings suggest that while flexible programming offers similar benefits to traditional fixed programs, it may require strategies to maintain adherence over longer periods,” the authors wrote.

Practical Implications for Remote and Endurance Athletes

For the endurance-focused audience, this study offers valuable lessons. The flexibility to swap a planned high-intensity interval session for a steady Zone 2 training day when feeling fatigued can still drive progress. This aligns with a holistic view of training where managing overall load and recovery is as important as the workout itself.

The remote application is particularly relevant. For populations like military personnel, travelers, or anyone without consistent access to specific equipment, a flexible model that adapts to changing environ (iron bisglycinate)ments can sustain training momentum. The research proves you don’t need a perfect, fixed schedule to improve.

The adherence warning is the study’s most practical insight. To make a flexible approach sustainable, trainees might use simple rules to reduce daily decisions. Examples include having a default “low-energy” workout (like a recovery row or walk), planning the week’s workouts in advance but allowing swaps, or using tools like heart rate variability to guide choice objectively. Integrating modalities like a rowing ergometer can also provide a full-body, low-impact option for days when running feels taxing.

Flexibility is Effective, But Structure Still Helps

This study validates a more intuitive, autoregulated approach to concurrent training. It demonstrates that listening to your body and adjusting daily exercise selection does not come at the cost of fitness gains. For endurance athletes balancing strength and cardio, this flexibility can be a tool to optimize recovery and long-term consistency, much like how understanding lactate and brain health informs broader training philosophy.

The key takeaway is not that rigid schedules are obsolete, but that effective training can take multiple forms. The fixed program worked. The flexible program worked just as well for the body, but required more mental effort to stick with. For long-term success, the most effective program may be one that blends a flexible framework with just enough structure to prevent decision fatigue from derailing consistency.

Source: Bonilla CP, Kilian JR, Herron RL. A Flexible Training Approach to Improving Concurrent Training Outcomes in Remote Trainees. Int J Exerc Sci. 2025;18(8):43-55. PMID: 39917430.