Negative Steps and Achilles Tendon Ruptures

Injuries are multifactorial and rarely have a simple answer.

Achilles tendon injuries stole the spotlight during the 2025 NBA playoffs, and many quickly blamed the so-called negative step, which was visible when Tyrese Haliburton ruptured his Achilles tendon in Game 7 of the NBA Finals. The negative step — also referred to as the false step or plyo step — has been found to be frequently associated with Achilles tenon ruptures (Lemme et al., 2019; Petway et al., 2022).

The negative step is seen almost any time anyone runs forward from a parallel stance (Kraan et al., 2001). The body naturally steps backward to create a more optimal body position for acceleration, setting up an inherent mechanical advantage by achieving a faster peak ankle angular velocity (PAAV) and decreasing time from zero to five meters (Schwenzfeier et al., 2022).

Speed expert Lee Taft, the originator of the term plyo-step, explained that athletes “instinctively reposition one foot behind their center of mass in order to have a proper force application angle to move the center of mass forward, or in whatever direction of travel. This action of repositioning the foot behind the body opens the joint angles of the knee and hip and creates a ‘stiffness’ that induces a stretch shortening cycle response (SSC), also known as an elastic response.”

Inadequate stiffness may separate advantageous plyo steps from the injurious negative steps. Injuries occurred with a long backward step far outside the base of support followed by an extreme and rapid increase in ankle dorsiflexion, frequently with an outwardly-turned foot (Lemme et al., 2019; Petway et al., 2022). Improving Achilles tendon stiffness may prevent reaching the end ranges where injuries occur and also improve the transfer of force from muscle to tendon (Petway et al., 2022). Optimizing the backward step is a better path forward than attempting to eliminate the movement, as has been suggested.

When I played, coaches spent years training a forward first step, as they believed the negative step slowed down players. We attempted to undue the instinctive or reflexive movements. As speed coach Charlie Francis wrote in Speed Trap, “The human body adjusts to small idiosyncrasies, and you tamper with them at your peril.” The short, explosive plyo step improves performance, but coaches spent generations attempting to change this reflex. Francis wrote, “All coaches have their own theories about technique. The best know when to adapt their theories to the idiosyncrasies of their athletes.”

The negative step occurs naturally — that is, without instruction or prompting — nearly any time anyone sprints from a parallel stance. Therefore, the step does not need to be taught. Instead, as Francis suggested, we simply need not tamper with the human body’s idiosyncrasies. Our theories of technique are not superior to the body’s instinctual movements. We need to use these reflexes, not change them.

Offensive basketball players rarely start from a parallel stance. A common triple-threat stance for a right-handed player is a left-foot pivot foot with the right foot in front of the left. Depending on the stance (how close to parallel), some players step back to go go forward. We often see this in the corner when players catch, shot fake, and go, and step out of bounds. The stance in these situations tend to be more parallel and upright, requiring the backward step to position the center of mass in front of the base of support (Kraan et al., 2001).

The triple-threat stance tends to be a lower, more flexed athletic position. Trainers began to teach the negative step to improve first-step acceleration from this lowered, staggered stance. This is a consequence of the rules governing the traveling violation and the perpetuation of the left-foot pivot foot.

I questioned the left-foot pivot foot for right-handed players in Hard2Guard Player Development Newsletters, Volume 7 and Fake Fundamentals, Volume 4. I argued the left foot is not a natural pivot foot as most basketball coaches suggest, but learned through habit, just as jumping off the left foot for a right-handed layup is a learned skill.

The left-foot pivot for right-handed players developed from the jab-step series. The game has changed, and these skills are less prevalent. Few players catch, hold the ball, and iso with the jab-step series like prime Carmelo Anthony. Why not question the resulting methods when the foundation of offensive basketball has changed?

Why is the left-foot pivot foot presumed to be advantageous if we eliminate the jab step, and especially the jab-and-shoot? The left-foot pivot foot sets up players to travel. Our natural gait is for the trail foot to step forward, but most players hold the ball with their right-foot forward. A right-foot pivot foot with the right foot forward affords a first step by the left foot, the trailing foot, which is the normal gait, and therefore one could argue, the more natural movement.

Trainers attempted to recreate the stretch-shortening response to improve their players’ acceleration by teaching the negative step. Players in the staggered stance with their left-foot as pivot foot step backward to create a more optimal position for a right-foot first step. Of course, this step backward is not the instinctive, natural plyo step, but a learned negative step. This learned movement may be too long or dorsiflexion too great for the system. The learned movement is not the instinctual, reflexive movement. The simplest solution is to adopt the right-foot pivot foot more frequently.

Despite the focus on the negative step, Achilles tendon ruptures are multifactorial injuries; you cannot pinpoint a single cause (Xergia et al., 2023). In a review of Achilles tendon ruptures in the NBA, 35% of injured players had missed at least one game for Achilles tendinitis or an Achilles tendon injury, and an additional 18% suffered from plantar fasciitis or foot inflammation or a previous ankle injury (Petway et al., 2025). Halliburton, as an example, was known to have a calf/Achilles problem before Game 7.

Additionally, the use of oral fluoroquinolones — a class of antibiotics — have been associated with increased risk of Achilles tendon rupture (Rasmussen et al., 2024). Similarly, corticosteroid use, typically oral, has been associated with increased Achilles tendinopathy and rupture (Data, 2005). A few players who have ruptured their Achilles tendons in recent seasons reportedly have used inhalers, which often include corticosteroids to reduce inflammation in the airways.

Additionally, I have followed a Belgian Osteopath named Frederic Van Burm for several years (Volume 7). He mentioned the connection between oral surgeries (such as root canals) and injuries, specifically Achilles tendon ruptures. Shortly thereafter, I had a player suffer an Achilles tendon rupture, and he had had a root canal during the previous summer. After seeing the injury connection first-hand, I paid attention when professional athletes injured their Achilles, and inquired, as much as possible, as to their oral health. Several players had dental work in the months preceding the injury. Correlation does not equal causation, but there is some evidence.

Integrative dentistry eschews root canals because they fear that it locks bad bacteria in the mouth, and this bacteria may circulate through the bloodstream (Hooper, 2017). Van Burm said in an interview, “If I only had the money to hire one doctor, I would choose a dentist and not a traditional doctor.” Periodontitis is like an ulcer under your gums, which can lead to difficult-to-detect changes in the immune system and recurring high-performance sports injuries (Limpens, 2014). Periodontitis is a painless mouth infection that athletes often do not notice for years (Limpens, 2014).

Specific sporting injuries have been associated with bacterial dissemination in the bloodstream, including Achilles tendinitis, although oral infections do not cause athletic injury (Budd & Egea, 2017). These infections may weaken tendons, which makes the tendon more susceptible to chronic and acute injuries. “These germs can wriggle through red, swollen gums and travel to the bloodstream, where they’re free to proliferate throughout the body triggering a harmful immune response far from the mouth” (Hooper, 2017). The Achilles tendon is vulnerable because it is hypovascular (Budd & Egea, 2017); there is limited blood flow. “Immunocomplexes and other inflammatory elements will tend to deposit around collagen fibers. This inhibits effective healing of an injured tendon,” (Budd & Egea, 2017). An injured tendon that does not heal may become a chronic injury, such as tendonitis, or the tendon may be compromised, resulting in a rupture. Additionally, poor oral health was associated with re-injuries such as repeated exercise-associated muscle cramps and muscle or tendon re-injury (Solleveld et al., 2015).

We like simple, causal answers: A caused B. We see injuries occur with a false step, and we blame the false step. The false step provides a simple, easy answer. Injuries are multifactorial.

There were reportedly eight Achilles tendon ruptures in the 2024-25 NBA season. Over 500 players appeared in the NBA during the 2024-25 season, each of whom makes dozens of false steps; some of whom make thousands of false steps each season. Injuries occur on a small fraction of one percent of all false steps. Why those specific few? Why are there not hundreds of Achilles tendon ruptures each year if the negative step is the sole cause?

Eliminating a natural, instinctive movement will not necessarily eliminate Achilles tendon ruptures just as flossing likely will not eliminate the injuries. We should examine the injuries holistically rather than attempting to eliminate a movement that optimizes performance.

First, rather than change or improve the movement, allow the instinctive movement; trust the body knows best. Second, improve the stiffness of the system through plyometrics and other training. Third, be cognizant of related injuries. Pain is a perception of a threat; the body’s attempt to signal danger, as Adrian Luow said at the 2013 Boston Sports Medicine and Performance Group conference. Listen to the body and uncover the cause of the danger. Finally, be aware of other factors, whether corticosteroids or periodontitis, and reduce these factors.

References

Lemme, N.J., Li, N.Y., Kleiner, J.E., Tan, S., DeFroda, S.F., & Owens, B.D. (2019). Epidemiology and video analysis of Achilles tendon ruptures in the National Basketball Association. The American Journal of Sports Medicine, 47(10), 2360-66.

Petway, A.J., Jordan, M.J., Epsley, S., & Anloague, P. (2022). Mechanisms of Achilles tendon rupture in National Basketball Association players. Journal of Applied Biomechanics, 38(6), 398-403.

Kraan, G.A., Van Veen, J., Snijders, C.J., & Storm, J. (2001). Starting from standing; why step backwards?. Journal of Biomechanics, 34(2), 211-15.

Schwenzfeier, A., Rhoades, J.L., Fitzgerald, J., Whitehead, J., & Short, M. (2022). Increased sprint performance with false step in collegiate athletes trained to forward step. Sports Biomechanics, 21(8), 958-65.

Xergia, S.A., Tsarbou, C., Liveris, N.I., Hadjithoma, Μ., & Tzanetakou, I.P. (2023). Risk factors for Achilles tendon rupture: An updated systematic review. The Physician and Sportsmedicine, 51(6), 506-16.

Petway, A.J., Burch, R.F., Saucier, D., Gillen, Z.M., Epsley, S., Forbes, R., ... & King, J. (2025). Examining prior injury relative to Achilles tendon ruptures in National Basketball Association players. Research in Sports Medicine, 1-12.

Rasmussen, P.V., Strange, J.E., & Holt, A. (2024). Oral fluoroquinolones and the risk of Achilles tendon rupture. Journal of Sport and Health Science, 13(6), 749.

Data, P. (2005). Corticosteroid-associated tendinopathies. Drug Safety, 28(7), 633-43.

Hooper, J. (2017). How oral health affects the rest of you. Men’s Journal, 26(5), 39-42.

Limpens, M. (2014). Hoe disbalans in de kaak het bewegingsapparaat beïnvloedt: Osteopaat Frédéric van Burm kent de triggers. PodoSophia, 22(1), 22-25.

Budd, S.C. & Egea, J.C. (2017). Sport and Oral Health: A Concise Guide. Springer.

Solleveld, H., Goedhart, A., & Bossche, L.V. (2015). Associations between poor oral health and reinjuries in male elite soccer players: a cross-sectional self-report study. BMC Sports Science, Medicine and Rehabilitation, 7(1), 11.