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Peak Performance Physical Therapy & Sports Training EVIDENCE-BASED PRACTICE UPDATE January 2024 Biomechanical Pitfalls Promoting Achilles Tendonitis in Recreational Runners by Andrew Neumeister, PT, DPT, FAFS, Certified Running Gait Analyst Clinical Scenario…What would you do? A 41 yr old male recreational runner with R achilles area pain developing gradually over the past 6 wks comes in for evaluation. Plain films are (-) and clinical exam shows tenderness on the R achilles tendon (AT) several cm above and down to the calcaneal insertion, painful vertical hopping and standing plantarflexion raising. Bilateral squat testing reveals limited ankle wb dorsiflexion while single leg squat shows asymmetric dynamic valgus and overpronation compared to the L side. He reports recently increasing weekly mileage from 20- - - >30 miles over his 4 days/week running frequency. I would … Order an MRI to confirm suspected achilles tendinopathy and R/O other possible causes. FU in 2 wks after starting a course of OTC NSAID’s to check progress and decide a plan of care. Advise rest from running for 4-6 weeks with a change to non-impact cross training options and FU in 4 wks. Prescribe a customized, biomechanical PT evaluation along with a running analysis to establish a customized functional exercise program geared to address any running pathomechanics. To include manual therapy, therapeutic taping trial, and Class IV laser therapy as indicated. Provide handout of standard calf stretching and ankle tubing resisted PF strengthening PRE with orders to reduce running mileage by 50% and frequency to BIW-TIW. Refer for custom orthotics evaluation and management along with non-impact cross training. FU in 4 wks. CURRENT EVIDENCE Skypala J, Hamill J et al. Running-Related Achilles Tendon Injury: A Prospective Biomechanical Study in Recreational Runners. J Appl Biomech. 2023 (online Jul 7), 39(4):237-245. https://journals.humankinetics.com/view/journals/jab/39/4/article-p237.xml We invite you to reach out to us at PT@peakptrochester.com or call our office at 585-218-0240 to further discuss this article in further detail if you wish. The abstract can be found after the case study. PEAK PERFORMANCE PERSPECTIVE Orthopedists and PCP’s often evaluate runners presenting with achilles tendon symptoms, easily discernible through palpation and painful resisted plantar flexion in weight bearing. Achilles tendonitis/tendinopathy (AT) is among one of the most common running related injuries (RRI), occurring up to 22% in recreational runners and has been shown to decrease running performance in up to 66% of runners during the first year after injury. Recommending treatment involves more than simply “routine” physical therapy as studies show that a running analysis can be helpful/necessary and contributing factors can easily be missed when simple “stretching and strengthening exercises'' PT concepts are ordered and employed. The study’s regression analysis showed that knee flexion angle increases at initial contact(IC) and midstance (MS) resulted in greater risk of AT - for every 1° of knee flexion angle increase; there was a 15% rise in AT risk. The authors hypothesized this may be related to alterations in the effective mechanical advantage of the gastroc complex. Dorsiflexion was also significantly greater at midstance. Foot strike patterns were not found to contribute. Clinically speaking we find that AT must involve a thorough biomechanical evaluation as there are numerous potential contributing factors, most of which were not analyzed or data not shown in this study. There are also many possible underlying reasons why a runner might exhibit this increased knee flexion angle at IC and MS. Merely being aware this finding is present does not indicate the actual cause that must be addressed with physical therapy. While coaching/cueing generic running form or cadence changes may temporarily alter symptoms and performance it is paramount that causative factors be identified so that tightness and/or weakness etc. are properly addressed so the compensatory abnormal knee flexion no longer is necessary in the first place. Further Details… Skypala 2023 et al. conducted a prospective biomechanical study in recreational runners to assess which mechanics during phases of running have influence on the RRI of AT. The authors reported that many previous cross sectional and retrospective studies conclude runners with AT have greater ankle dorsiflexion and eversion during the loading phase of running, and also noting conflicting reports showing either increased and decreased knee flexion during stance phase. These studies, however, were performed on runners already having AT, therefore do not confirm causal relationships but may reveal compensatory patterns due to pain. Skypala et al. set out to determine whether biomechanical variables were related to the incidence of RRI AT for one year in low-volume runners. The authors defined an AT RRI as pain in the AT region requiring medical evaluation or resulting in limited/cease of running for at least 7 days or 3 consecutive running sessions. Of the 318 original participants who met the inclusion criteria were 108 recreational runners aged 18 - 65 yr old with a weekly mileage under 51 km/wk and were free of musculoskeletal lower extremity injuries 6 months prior to the study. A 10 camera motion analysis biomechanical assessment using 24 markers while using a self-selected speed (for 45 min run pace) over a 17m force plate runway while wearing provided “neutral” running shoes was done, analyzing R side mechanics for this study. The authors reported that 26 (15 males and 11 females) or 25% of the final 103 participants completing the study had R sided AT within one year after biomechanical analysis, with 18 runners (17%) developing (B) AT. Biomechanical predictors that were associated with development of RRI AT were an increased knee flexion angle at initial contact (OR=1.146, P = .034) and midstance phase (OR=1.143, P=.037). Therefore, a 1° increase of knee flexion at initial contact (IC) and midstance (MS) was associated with a 15% increase in risk of developing RRI of AT. Runners with AT also showed significantly increased dorsiflexion (P=.010, ES=0.630) during stance phase and at baseline had lower body fat % (P=.041, ES=0.491) and reported more mod-vigorous activity (P=.048, ES=0.630). Foot strike pattern was not a risk factor (OR=0.997, P=.807). Effective mechanical advantage (EMA) of the medial and lateral gastroc reduce as the increase in both the knee and ankle flexion angles causes larger external flexion moments which then require greater muscle force to decelerate and then propel the body. The authors proposed this as a potential mechanism for the achilles overloading. Skypala et al’s study does have some important limitations that must be considered. As an endurance runner myself, it can often take time to establish your preferred speed in a study like this where runners were crossing a 17m over 6 minutes and stop/starting at each end. Simply cueing someone to run at a “45 min running pace” cannot simply be established in 6 minutes of inconsistent running. Runners used a “neutral” running shoe which does not account for each individual's preferred footwear during testing, thus potentially causing modifications from their otherwise typical running mechanics but also is then not the same footwear used during the subsequent year of running for the study. Foot dynamics were not assessed during the study thus no data regarding pronation and supination mechanics, with any over-the-counter orthotics, “pronation control”, or minimalist footwear used during training were analyzed. DF angles during IC and MS may be altered depending on different heel drop heights between shoes. The amount of calcaneal eversion can also be variable in control depending on orthotic design or the footwear itself. All of those factors above can influence the stress on the AT during running that was not accounted for during motion analysis in the lab. Regarding foot strike patterns it would require further analysis as to whether an adequate variability and number of participants having differing foot strike tendencies to power finding significant differences were present in the study. Why does any of this matter when recommending an appropriate treatment plan? It is not as simple to tell your patient to reduce their DF and knee flexion angle while on a run to reduce mechanical stress. The data suggests that reducing peak knee flexion and dorsiflexion angle reduces tension on the achilles tendon through improvement in their biomechanics, however does not address how to take this knowledge and then apply it to appropriate treatment methods. It is not inherent for patients and many therapists to know how to provide proper functional treatment while rehabilitating AT taking account of the dynamic activity which caused them to seek medical attention. A specific biomechanical evaluation assessing running form and technique using 2D motion analysis allows for the therapist and patient to visualize where external joint angles can increase stress on the entire lower extremity system contributing to AT pain and other common running injuries at each of the ankle, knee, and hip complexes. Ankle/foot mechanics need to also be assessed to determine where limitations in mobility or pronation control could exist as biomechanical pitfalls. Correction utilizing an appropriate orthotic can aid in reducing stress to the system caused by ground up tibial internal rotation and subsequent dynamic valgus. A functionally trained physical therapist with knowledge of running biomechanics can establish a return to running program with necessary cues to reduce impact stress during the stance phase from start to finish. Anderson et al. reported that increasing cadence has been shown to have a large effect on reducing peak ankle DF and knee flexion angles. Through an appropriate biomechanical evaluation and treatment geared specifically to the runner’s goals, results can be obtained quicker by addressing specific biomechanical results. While Skypala et al. used a large group prospectively to better understand commonalities among runners developing AT, it must also be remembered that each individual runner brings unique physical abilities and limitations that potentially affect risk of developing AT. More in-depth biomechanical kinetic chain assessments must be included for effective physical therapy care beyond merely utilizing group findings such as from this study, especially considering the variety of kinetic and kinematic information not analyzed here. A variety of limitations such as limited ankle DF, abnormal foot mechanics leading to prolonged overpronation during propulsion phase, poor contralateral propulsion or swing phase function, proximal hip Abductor and/or ER’s weakness, and weak quadriceps among others have all been findings we’ve noted that potentially have contributed to AT cases in runners. THE PEAK PERFORMANCE EXPERIENCE A 1° increase of knee flexion at initial contact (IC) and midstance (MS) was associated with a 15% increase in risk of developing RRI of AT. At a cadence of 150-160, the peak knee flexion ankle at midstance is 50°. Below are images of the author running at 7.5 mph speed at 8 different cadences ranging from: 150 steps/min to 220 steps/min increasing by 10’s respectively. A reduction of knee peak knee flexion reduces as cadence increases, down to 32° at 220 steps/min. 1. 2. 3. 4. 5. 6. 7. 8. (angles are calculated by (180° - X deg. below) Skypala J, Hamill J et al. Running-Related Achilles Tendon Injury: A Prospective Biomechanical Study in Recreational Runners. J Appl Biomech. 2023 (online Jul 7), 39(4):237-245. Abstract Background: Few running studies have attempted to prospectively identify biomechanical risk factors associated with Achilles tendonitis injuries. Many studies have been done retrospectively on individuals with AT and have not identified if the results are mere correlation and not causation. Purpose: The authors set out to determine what potential factors there may be associated with developing AT in healthy recreational runners. Type: Prospective Study Methods: 103 healthy recreational runners had their kinematics and kinetics assessed with a motion analysis system at a self selected running speed. They then completed weekly questionnaires at home for the following year to determine if they had developed AT per the authors definition of the running related injury. Findings: A more flexed knee at initial contact and at the midstance phase were significant predictors for developing the Running Related Injury of AT. Runners who had a significantly greater maximal ankle dorsiflexion during the stance phase also were found to be a risk factor for developing AT. Author's Conclusion: The incidence of running related AT over a 1-year prospective evaluation was 30%. Participants with AT RRI ran with greater angles of knee flexion and dorsiflexion during stance phase. This potential risk factor could be attributed to a mechanical disadvantage of the gastrocnemius complex with a flexed knee. The effective mechanical advantage is reduced as external moment arms increase at the knee angle ankle with individuals exhibiting greater knee flexion and ankle DF. (Citation for evidence regarding the effect of cadence on running kinematics) 2. Anderson LM, Martin JF, Barton CJ, Bonanno DR. What is the Effect of Changing Running Step Rate on Injury, Performance and Biomechanics? A Systematic Review and Meta-analysis. Sports Med Open. 2022 Sep 4;8(1):112. doi: 10.1186/s40798-022-00504-0. PMID: 36057913; PMCID: PMC9441414. You can trust the Physical Therapists at PEAK PERFORMANCE to do a thorough evaluation, to search for related but underlying contributing factors to kinetic chain dysfunction, and to design exercise progressions that both respect tissue healing and creatively use biomechanics principles to prevent symptoms and optimize carryover to your patients' functional goals. Call us at 218-0240 to discuss your patient's specific needs. Peak Performance is just minutes away from your patients in Penfield, Fairport, Pittsford, Brighton, Rochester and, of course, East Rochester. We promise Individualized, hands-on and biomechanically appropriate Physical Therapy for your patients. No "one-size-fits-all" approaches. We WILL go the extra mile and "dig deeper" to discover underlying causes for injury risk and delayed recovery using the most advanced Evidence Based methods available and, we’re able to make unique adjustments to exercise prescriptions to speed the return to function and to minimize or prevent symptoms from interfering. No surprises. No hassles. Confident your patient is in the right place. COME VISIT US AT 161 E Commercial St Just 1 mile off 490 exit (585) 218-0240 www.PeakPTRochester.com