Moving Beyond Weekly “Distance”: Optimizing Quantification of Training Load in Runners

Abstract

U BACKGROUND: Quantifying total running distance is valuable, as it comprises some aspects of the mechanical/neuromuscular, cardiovascular, and perceptual/psychological loads that contribute to training stress and is partially predictive of distancerunning success. However, running distance is only one aspect contributing to training stress. U CLINICAL QUESTION: The purpose of this commentary is to highlight (1) problems with only using running distance to quantify running training and training stress, (2) the importance of alternative approaches to quantify and monitor training stress, (3) moderating factors (effect-measure modifiers) of training loads, and (4) the challenges of monitoring training stress to assess injury risks. U KEY RESULTS: Training stress is influenced by external (ie, application of mechanical load) and internal (ie, physiological/psychological effort) training load factors. In running, some commonly used external load factors include volume and pace, while physiological internal load factors include session rating of perceived exertion, heart rate, or blood lactate level. Running distance alone might vastly obscure the cumulative training stress on different training days and, ultimately, misrepresent overall training stress. With emerging and novel wearable technology that quantifies external load metrics beyond volume or pace, the future of training monitoring should have an ever-increasing emphasis on biomechanical external load metrics, coupled with internal (ie, physiological/psychological) load metrics. U CLINICAL APPLICATION: It may be difficult to change the running culture's obsession with weekly distance, but advanced and emerging methods to quantify running training discussed in this commentary will, with research confirmation, improve training monitoring and injury risk stratification.

Sacral acceleration can predict whole-body kinetics and stride kinematics across running speeds

“…However, peak vGRF, vertical impulse, and contact time are typically quantified using expensive and immobile force plates or force-measuring treadmills. Wearable devices provide a method for monitoring external loading variables longitudinally outside of a laboratory ( Paquette et al, 2020 ), but the ability to simultaneously predict peak vGRF, vertical impulse, and contact time during running using a single wearable device and the accuracy of these predictions is not known. Predicting these biomechanical variables with a single wearable device could allow researchers, clinicians, and coaches to monitor external loading variables associated with bone loading magnitude and duration without the need of force-measuring equipment.…”

Comparison of different measures to monitor week-to-week changes in training load in high school runners

“…For example, a runner’s training volume could remain constant during two consecutive training days or weeks despite increases in intensity and resulting physiological response. 5 This misrepresentation of training stress could lead to maladaptation or periods of non-functional overreaching in runners. On the other hand, training load measures likely provide a more individualized assessment of the physiological training response 13 and overall training stress experienced by a runner.…”

“…On the other hand, training load measures likely provide a more individualized assessment of the physiological training response 13 and overall training stress experienced by a runner. 5 Thus, we urge coaches to consider thinking beyond just weekly volume and to incorporate measures of training loads in their monitoring approaches. This might be particularly important for inexperienced coaches, those who oversee the training of many runners, and those who oversee remote training (i.e., limited in-person and direct communication with athletes).…”

“…Many factors can contribute to these varied responses for individual runners in %Δ among different training load measures including emotional/psychological state (e.g., family, school, relationship stress) and different changes in specific external load metrics due to higher training load (e.g., different cadence, different intensity of steps, different pace, etc.). 5 Thus, future work should assess individual factors that might contribute to this individual response to various training load measures.…”

“…3 Historically, most runners and coaches have used external load factors such as volume (e.g., distance or duration) and intensity (e.g., pace) to quantity running training as these methods are engrained in the running culture. 4–7 However, there may be more appropriate and effective methods to monitor training stress in runners. A better understanding of and improvements in methods to quantify training stress should help coaches optimize running performance.…”