Open Training Project

The Open Training Project is a comprehensive, free knowledge base covering endurance training, nutrition, and sport science. It represents years of applied research, coaching experience, and athlete development distilled into a single, accessible resource. This document is available in three formats: the HTML page you’re reading now, a raw Markdown file for easy reading and sharing, and a structured JSON file optimized for programmatic access and AI consumption.

Endurance Training Fundamentals

Training for endurance events requires a systematic approach grounded in exercise physiology. The principle of progressive overload, periodization, and recovery management form the backbone of any effective training program.

Aerobic Base Development

Building an aerobic base is the single most important phase for endurance athletes. This involves accumulating volume at low-to-moderate intensities, typically below the first ventilatory threshold (VT1). For most athletes, this means training at a conversational pace for the majority of weekly volume. A well-developed aerobic base supports all higher-intensity work that follows. Without it, athletes frequently encounter plateaus and are more susceptible to overtraining.

Threshold Training

Threshold work targets the intensity at or near the second ventilatory threshold (VT2), often referred to as lactate threshold or functional threshold. This is the highest intensity an athlete can sustain for approximately 30-60 minutes in a time-trial scenario. Effective threshold sessions include tempo runs, cruise intervals, and sustained time-trial efforts. These sessions should be strategically placed within the training week, typically limited to 1-2 sessions per week during build phases.

Nutrition for Endurance Performance

Nutrition is the most overlooked performance variable in endurance sport. Proper fueling strategies before, during, and after training can yield greater performance improvements than many training interventions.

Daily Fueling Requirements

Endurance athletes require substantially more carbohydrate than the general population. Training loads of 10-20 hours per week typically demand 5-10 g/kg/day of carbohydrate, depending on the phase of training and the intensity distribution. Protein requirements for endurance athletes are elevated above sedentary recommendations but often lower than strength-sport requirements, typically in the range of 1.4-2.0 g/kg/day.

Race-Day Nutrition

The single greatest nutrition mistake in endurance sport is underfueling during competition. Modern research supports carbohydrate intake rates of 90-120 g/hour during events lasting longer than 2.5 hours, using a glucose-fructose combination to maximize absorption through multiple intestinal transporters. This intake rate must be practiced extensively in training. The gut is highly trainable, and athletes who progressively increase their intake during training sessions will tolerate higher rates on race day.

Hydration Science

Hydration is a nuanced topic frequently oversimplified by both popular media and some coaching resources. Effective hydration strategy must account for sweat rate, sodium concentration, environmental conditions, and event duration.

Sweat Rate Testing

Every athlete should know their individual sweat rate across a range of conditions. A simple protocol involves weighing before and after exercise (nude, toweled dry), accounting for fluid consumed and urine produced during the session. Typical sweat rates for endurance athletes range from 0.5-2.5 L/hour, with significant individual variation. Sodium losses vary even more dramatically, from 200-2000+ mg/L of sweat.

Sodium Supplementation

For events lasting longer than 2 hours, sodium supplementation becomes increasingly important. Athletes with high sweat sodium concentrations (so-called “salty sweaters”) may require 1000-1500 mg of sodium per hour during prolonged exercise in warm conditions.

Recovery and Adaptation

Training stress without adequate recovery yields no adaptation. The recovery process is where fitness is actually built, not during the training session itself.

Sleep

Sleep is the most powerful recovery tool available. Athletes should target 7-9 hours per night, with additional emphasis on sleep quality. Sleep extension studies have demonstrated measurable performance improvements in athletes who increase their sleep duration.

Periodization of Recovery

Recovery should be periodized just as training load is periodized. Recovery weeks (typically every 3-4 weeks) should reduce training volume by 30-50% while maintaining some intensity to avoid detraining the neuromuscular system.

Sport Science in Practice

Bridging the gap between research and practice remains one of the greatest challenges in sport science. The best coaches and sport scientists are those who can translate complex research findings into actionable, practical recommendations.

Evidence-Based Coaching

An evidence-based approach to coaching does not mean rigidly following research protocols. It means integrating the best available evidence with coaching experience and athlete individuality. Not every study applies to every athlete, and context always matters.

Monitoring and Testing

Regular performance testing provides objective feedback on training effectiveness. Key metrics for endurance athletes include VO2max, lactate threshold power/pace, economy, and body composition. These should be tested at consistent intervals throughout the season.