How injuries affect performance, recovery, and athlete identity

Originally published on March 21, 2023

Injury risk and recovery depend on more than a rehab plan. Sleep, fueling, menstrual health, training load, and mental stress all shape how fast an athlete breaks down and how well that athlete returns to play.

In Episode 214 of the WHOOP Podcast, Global Head of Human Performance, Principal Scientist at WHOOP Kristen Holmes speaks with Dr. Kate Ackerman, founder and director of the Wu Tsai Female Athlete Program at Boston Children's Hospital and associate professor of medicine at Harvard Medical School. Ackerman explains why stress fractures, relative energy deficiency in sport, and athlete identity often sit on the same continuum, especially for girls and women whose training demands rise faster than their recovery habits.

To listen to episode 214 in full, head to the WHOOP Podcast on YouTube.

Why do injuries affect mental health as much as physical performance

Injuries disrupt tissue, training, routine, and identity at the same time. Ackerman treats recovery as a whole-athlete problem, because the same stress fracture or ligament tear can also remove structure, confidence, and connection to a team.

That framing shapes the questions she asks in clinic. A diagnosis matters, but Ackerman also wants to know what led to the injury, how the athlete is coping, and what a safe return to play will require. For an athlete who has built daily life around practice, competition, and progress, an injury can feel like a sudden loss of purpose.

She also points to the wider pressures athletes carry away from sport. Academic load, family strain, relationship stress, political events, and social pressures can all affect how an athlete feels and performs. Ackerman gave the example of women basketball players who were deeply affected during the Black Lives Matter movement, even when they still looked composed on the court. In her view, those outside stressors belong in the performance conversation.

That broader view is one reason the United States Olympic & Paralympic Committee has invested more heavily in mental health support. Ackerman noted that earlier generations of athletes were taught to stay tough and stay quiet. Current athletes are more likely to speak openly about stress, depression, and the emotional cost of setbacks, which gives coaches and clinicians a better chance to respond before a bad stretch becomes a long spiral.

Ackerman told Holmes that her job goes beyond naming the injury.

"When I have a female athlete come into my clinic and they've had a stress fracture, A, what led to the stress fracture? B, how are they coping with that stress fracture? C, how are we getting them back into play safely?"

What you should take away

• Injury recovery includes mental health, identity, and social connection, alongside tissue healing.
• Outside stressors such as school, family strain, and current events can show up in performance and recovery patterns.
• Athletes who talk openly about mental health challenges give coaches and clinicians more room to intervene early.

If you want to hear Ackerman go deeper on the link between injury, identity, and mental health, listen to the full episode on Spotify.

How can low energy availability lead to stress fractures and setbacks

That whole-athlete view leads directly to one of the clearest injury patterns Ackerman sees in clinic. Low energy availability, which is central to relative energy deficiency in sport, or RED-S, can lower hormone levels, impair bone health, and raise the risk of stress fractures.

Ackerman described a common progression. A young athlete trains hard, gets leaner, feels faster, and believes the plan is working. Short term performance may improve. Then the pattern stops being sustainable. Menstrual cycles become irregular or disappear, bone density falls, recovery suffers, and injuries arrive. In clinic, Ackerman often sees delayed periods, loss of periods after menarche, and low bone density showing up together.

Her message to athletes is direct: early success under low fueling does not last. The athlete has not found a shortcut. The athlete has entered a higher risk state that often ends with a forced stop.

Ackerman also stressed that RED-S is not always a deliberate choice. Exercise can suppress appetite, so athletes who increase training load may still fail to eat enough. She cited work from the Australian Institute of Sport in rowers showing that athletes who increased training by 20 percent did not automatically increase intake, even when food was fully available. Intent matters less than whether energy intake keeps pace with the work.

Rigid eating patterns can add another layer. Ackerman said highly restrictive clean eating styles can hide energy deficiency, leave athletes short on micronutrients, and create the same downstream problems as more obvious restriction. That concern overlaps with patterns discussed in WHOOP coverage of eating disorders and their impact on performance, especially when athletes tie thinness to validation or speed.

Ackerman summed up the clinical warning signs in one sentence.

"If I have a female athlete who is delayed in getting her period, or she gets her period and then loses it because she's not eating enough, or she's really, really stressed [...] that is a huge risk factor for stress fracture."

What you should take away

• Low energy availability can reduce hormone levels, lower bone density, and increase stress fracture risk.
• Early performance gains from underfueling are temporary and often give way to plateau, breakdown, or injury.
• Appetite suppression after training increases can make RED-S inadvertent, even when food access is not the problem.
• Rigid clean eating patterns can mask calorie and micronutrient gaps that slow recovery and raise injury risk.

If you want to hear Ackerman unpack how menstrual disruption and stress fractures intersect, watch the full episode on YouTube.

What is the Female Athlete Resilience Study trying to measure

Low energy availability is one pathway into injury. Ackerman is also trying to measure the wider set of forces that shape how female athletes tolerate training, stress, and recovery.

She told Holmes that female athletes remain underrepresented in sports science, citing an estimate that only 6 percent of sports science studies in recent years focused solely on women. That gap affects everything from menstrual cycle research to load management, sleep, and emotional stress. Ackerman wants female athlete data that is specific enough to guide real world decisions, instead of asking women to fit models built mainly from male participants.

The Female Athlete Resilience Study reflects that goal. Working with Boston College student athletes, the study combines qualitative interviews, validated surveys, and WHOOP bands with biologic samples to build a fuller picture of readiness and breakdown. Ackerman described questionnaires on sleep patterns, mood state, depression, and school workload, alongside physiologic data and blood, urine, or saliva measures.

The aim is to find practical surrogates. Daily blood draws over long periods are expensive and hard on participants. If a wearable pattern, a saliva marker, or a survey trend can stand in for a harder-to-capture signal, researchers can study larger groups and give athletes more usable feedback. That same spirit sits behind other WHOOP research, including Project PR, which examined how Recovery-guided training affected performance and injury rates in runners.

Ackerman put the research gap bluntly.

"Only 6% of research studies in sports science were focused solely on women."

What you should take away

• Female athlete research still lacks direct data, which limits how precisely coaches and clinicians can individualize training and recovery.
• The Female Athlete Resilience Study combines interviews, surveys, biologic samples, and WHOOP data to capture the full load an athlete carries.
• Practical surrogate markers could make menstrual health and stress research easier to scale beyond small lab settings.

For Ackerman's full take on why female athlete research needs better data, listen to the full episode on Spotify.

How should athletes recover mentally and physically after an injury

Those research gaps show up most clearly in rehab. Injury recovery needs active movement, enough food, enough sleep, and support for the identity shock that comes with losing normal training.

Ackerman sees many driven athletes struggle when their routine breaks. She tells them there is almost always something they can do physically. A concussed athlete may be able to walk. An athlete with a broken leg may still train the upper body. Preserving some movement helps protect mood, routine, and the feeling of being engaged in the process.

She also pushes athletes to build interests away from sport. Learning an instrument, taking up cooking, or studying a new language can help fill the empty space that opens when training volume drops. That advice becomes especially important for athletes whose sense of self has narrowed around one role.

Fueling remains central during rehab. Ackerman said she has seen athletes respond to major injuries such as ACL tears or femoral neck fractures by eating less because they believe they are burning fewer calories. That instinct can slow healing. Repair still requires energy, and further hormonal disruption can deepen the problem.

Her own work on bone stress injuries shows how long the body can stay in a vulnerable state after symptoms improve. Ackerman described a study of women with tibial bone stress injuries, grades 2 through 4 on MRI, in which bone microarchitecture looked worst about 12 weeks after injury and took another 12 weeks to return to baseline. Athletes are often running again by the time those deeper bone changes are still recovering.

Ackerman highlighted the timeline in specific terms.

"We found that bone microarchitecture drops and is at its worst about 12 weeks after the stress injury [...] it would take them another 12 weeks to get back to baseline."

What you should take away

• Injury rehab works better when athletes keep some form of safe movement in the schedule.
• Fueling needs remain high during rehab because tissue repair and hormonal stability both require energy.
• Interests outside sport can reduce the identity crash that often follows a long layoff.
• Bone recovery can lag behind symptom relief, so return to play timelines need more than a pain check.

If you want to hear Ackerman go deeper on return to play after a major setback, watch the full episode on YouTube.

Which daily habits help athletes stay available over time

Once rehab starts to stabilize, the conversation shifts from acute healing to long term availability. Ackerman's rule is simple: train smarter, not harder.

For her, the biggest gains come from consistency and self-observation. WHOOP makes that process easier by helping athletes see how sleep, alcohol, travel, and life stress affect next day readiness. Ackerman shared a small example from a friend who learned that red wine hurt next day recovery while tequila was easier to tolerate. The point was not the specific drink. The point was individual response.

Sleep sits near the top of the list. Ackerman said earlier generations of athletes treated sleep like an afterthought, often focusing only on the night before competition. Her current approach is steadier. Sleep is a training input every day, and poor sleep should change how an athlete thinks about load that day.

She applies the same logic to exams, work travel, and other life stressors. If the rest of life is demanding more from the body, training has to give somewhere. WHOOP members can use daily trends in Sleep, Recovery, and Strain to see when that adjustment may be warranted. The same principle runs through WHOOP education on Recovery and mobility and injury prevention.

Ackerman also noted that female athletes need to change training as they age. More rest, more strength work, and more variety matter. Repeating the same sessions year after year can keep an athlete busy without moving performance forward.

Her practical rule for overloaded periods is direct.

"If you are traveling for work or you have exams and you're staying up late to study for them, you're gonna have to back off on your training."

What you should take away

• Long term availability depends on consistent sleep, fueling, and training adjustments that match real life stress.
• WHOOP can help athletes spot personal patterns, including how alcohol, travel, and sleep loss affect next day readiness.
• Training plans should change with age, workload, and recovery capacity, rather than repeating the same routine indefinitely.

The bottom line

• Injuries change more than tissue status, because they also disrupt identity, routine, confidence, and social connection.
• Low energy availability is a major risk factor for stress fractures, menstrual disruption, and slower recovery.
• Female athlete research still lacks enough women-specific data, which limits how precisely training and rehab can be individualized.
• Return to play should account for deeper recovery timelines, because tissue quality can lag behind symptom improvement.
• Sleep and fueling remain central during rehab, even when training volume drops.
• Outside stress from school, work, travel, or current events can change recovery and performance as much as physical training does.
• WHOOP trends are most useful when athletes use them to adjust behavior, rather than treat a single score as a verdict.

Frequently asked questions about things discussed in this episode

How does WHOOP measure Recovery during injury rehab?

WHOOP measures Recovery from overnight physiology, including heart rate variability, resting heart rate, sleep, and respiratory rate. During rehab, those signals can help show whether the body is handling life stress and training load well, even though WHOOP does not diagnose the injury itself.

What does WHOOP help athletes notice about life stress outside training?

WHOOP helps athletes see that school pressure, travel, alcohol, and poor sleep can change next day readiness. That kind of pattern tracking supports the whole-athlete approach Ackerman described, where physical and emotional stress both affect performance.

How does WHOOP help with patterns related to low energy availability?

WHOOP can highlight patterns that may accompany low energy availability, such as reduced recovery tolerance, poor sleep, or difficulty bouncing back from normal training. RED-S still requires clinical evaluation, especially when menstrual function, bone health, or nutrition concerns are involved.

What does WHOOP show when an athlete needs to back off training?

WHOOP shows how recent strain and overnight recovery metrics are trending, which can help athletes spot periods when load may need to come down. Ackerman's advice in those moments is to adjust training when exams, travel, or sleep loss are already increasing stress.

How can WHOOP support return to play after an injury?

WHOOP can support return to play by giving athletes and clinicians a clearer view of sleep, strain tolerance, and recovery trends across rehab. That added context is useful when symptoms are improving but the body may still be rebuilding deeper capacity.

What does WHOOP reveal about alcohol and next day performance?

WHOOP often makes the next day cost of alcohol easier to see through sleep and recovery changes. Ackerman's example was individual, which fits the broader point that athletes respond differently and benefit from tracking their own patterns.

For athletes trying to stay healthy through setbacks, WHOOP helps connect sleep, strain, and recovery trends to the exact stressors Ackerman says often decide whether healing stays on track.