Hypothetically, what might be the best way to
build running intensity with these athletes?
Athlete scenario #1: Athlete with a history of multiple BSIs with compromised bone density.
Athlete scenario #2: Athlete with a history of one BSI and normal bone density.
[Please note: this is NOT specific medical advice]
Current point in training for BOTH athletes: Athlete #1 and #2 have successfully made it through the rehab phase post-BSI. They are meeting all daily & training nutritional needs and have successfully, gradually, and methodically built up to running 3 days a week for 60 minutes over the last 4 months at an easy pace. (4 months is an important point in time and will be explained later).
Training goal for BOTH athletes: Gradually introduce training intensity or speed work to prepare for a half marathon. No specific date for the half marathon has been set as the athletes have chosen to put their gradual return to healthy running before a specific date in time.
First, why is 4 months an important point in time?: Physiologically, 3 months is the minimum time it takes for full mineralization of cortical bone. Meaning, this athlete has successfully managed one cycle of the normal physiological process of bone microdamage related to easy pace running with the coordinated effort of bone-resorbing osteoclasts removing damaged bone and bone-forming osteoblasts filling gaps with new bone. For the most part this athlete is showing that he/she is managing appropriate nutritional needs, pacing, and recovery for the body to manage the normal physiological bone repair process.
What would be the most appropriate starting point for speed work?: First, it’s important to understand that bone is highly sensitive to the magnitude or intensity of load. “There is a strong correlation between the magnitude of the bone tissue stress/strain and the number of cycles before bone fatigue failure.” Ie, higher running intensity = less foot contacts before bone failure. This includes trail running, specifically running downhill.
“It is estimated that a 10% increase in tissue stress/strain results in halving the number of loading cycles before failure.” Or restated positively: “ a moderate (<10%) gain in bone mass induced by a loading program can generate a large and exponential (>100 fold) gain in bone fatigue resistance as a result of less tissue-level strain being experienced during each fatigue loading cycle.” - Warden et. al, 2021
Based on the above information + each athletes’s bone health history, the starting point for speed work, reviewed below, may be most beneficial for each athlete.
Athlete #1: Initially REDUCE weekly training volume to reduce total stress/strain on the bone when adding speed work. Stay very conservative when building intensity and consider having athlete run on a slight uphill vs. flat ground. Avoid downhill training for a period of time as the athlete adapts. Continue to follow all bone workload recommendations to maintain bone mechanosensitivity to the applied stress + normal physiological bone microdamage management process. Being conservative is key here due to compromised bone health!
Athlete #2: Initially REDUCE weekly training volume to reduce total stress/strain on the bone when adding speed work. Continue conservatively x 1-2 months or 1-2 bone remodeling cycles to determine how the athlete responds. May be slightly more progressive with speed work, utilizing the Acute: Chronic Workload ratio after a few months of successful implementation of speed work. It’s important to stay vigilant to the fact that one stress fracture is a predictor of future stress fractures, however, due to this athlete’s normal bone density, if he/she is responding in a healthy way over the first few months of a very conservative program, judicially progressing intensity may be ok with constant monitoring.
The above scenarios are hypothetical and by no means a prescription for activity. Please consult with a qualified DPT/Coach for specific help.
It’s always my pleasure to offer guidance. You deserve to find the healthy path to your performance goals!
Resource:
Warden, S., Edwards, W., & Willy, R. (2021). Preventing Bone Stress Injuries in Runners with Optimal Workload. Current Osteoporosis Reports, 19, 298 - 307. https://doi.org/10.1007/s11914-021-00666-y.