How many runners with new-onset Achilles tendinopathy develop persisting symptoms? A large prospective cohort study

Epidemiology of insertional and midportion Achilles tendinopathy in runners: A prospective cohort study

BACKGROUND

Achilles tendinopathy (AT) is a common problem among runners. There is only limited evidence for risk factors for AT, and most studies have not defined the AT subcategories. No study has compared the incidence and risk factors between insertional AT and midportion AT, though they are considered distinct. This study aimed to assess incidence and risk factors of AT based on data from a large prospective cohort. The secondary aim was to explore differences in risk factors between insertional and midportion AT.

METHODS

Participants were recruited from among registered runners at registration for running events. Questionnaires were completed at baseline, 1 month before the event, 1 week before the event, and 1 month after the event. Information concerning demographics, training load, registered events, and running-related injuries were collected at baseline. The follow-up questionnaires collected information about new injuries. A pain map was used to diagnose midportion and insertional AT. The primary outcome was the incidence of AT. Multivariable logistic regression analysis was applied to identify risk factors for the onset.

RESULTS

We included 3379 participants with a mean follow-up of 20.4 weeks. The incidence of AT was 4.2%. The proportion of insertional AT was 27.7% and of midportion AT was 63.8%; the remaining proportion was a combined type of insertional and midportion AT. Men had a significantly higher incidence (5%, 95% confidence interval (95%CI): 4.1%-6.0%) than women (2.8%, 95%CI: 2.0%-3.8%). AT in the past 12 months was the most predominant risk factor for new-onset AT (odds ratio (OR) = 6.47, 95%CI: 4.27 -9.81). This was similar for both subcategories of AT (insertional: OR = 5.45, 95%CI: 2.51-11.81; midportion: OR = 6.96, 95%CI: 4.24-11.40). Participants registering for an event with a distance of 10/10.55 km were less likely to develop a new-onset AT (OR = 0.59, 95%CI: 0.36-0.97) or midportion AT (OR = 0.47, 95%CI: 0.23 -0.93). Higher age had a significant negative association with insertional AT (OR = 0.97, 95%CI: 0.94-1.00).

CONCLUSION

The incidence of new-onset AT among recreational runners was 4.2%. The proportion of insertional and midportion AT was 27.7% and 63.8%, respectively. AT in the past 12 months was the predominant risk factor for the onset of AT. Risk factors varied between insertional and midportion AT, but we could not identify clinically relevant differences between the 2 subtypes.

Do physical tests have a prognostic value in chronic midportion Achilles tendinopathy?

OBJECTIVES

To determine whether baseline physical tests have a prognostic value on patient-reported outcomes in Achilles tendinopathy.

DESIGN

Prospective cohort study, secondary analysis of data from a randomized trial.

METHODS

Patients with chronic midportion Achilles tendinopathy performed a progressive calf muscle exercise program. At baseline and after 2, 6, 12 and 24 weeks, patients completed the Victorian Institute of Sports Assessment-Achilles questionnaire and performed the following physical tests: ankle dorsiflexion range of motion with a bent knee or an extended knee, calf muscle strength, jumping height and pain on palpation (Visual Analogue Scale; 0-100) and after 10 hops (Visual Analogue Scale-10-hops). Associations between baseline test results and improvement (Victorian Institute of Sports Assessment-Achilles scores) were determined using a Mixed Linear Model.

RESULTS

80 patients were included. The mean Victorian Institute of Sports Assessment-Achilles score improved 20 points (95 % confidence interval, 16-25, P < .001) after 24 weeks. There were significant associations between the baseline ankle dorsiflexion range of motion with a bent knee (β 0.2, 95 % confidence interval 0.001 to 0.3, P = .049), the baseline pain provocation tests (Visual Analogue Scale palpation: β -0.2; 95 % confidence interval: -0.4 to -0.1; P < .001, Visual Analogue Scale-10-hops: β -0.3; 95 % confidence interval: -0.4 to -0.2; P < .001) and the change in the Victorian Institute of Sports Assessment-Achilles score.

CONCLUSIONS

In patients with chronic midportion Achilles tendinopathy, easy-to-perform pain provocation tests have a clinically relevant prognostic value on patient-reported improvement. Patients with less pain during pain provocation tests at baseline have a better improvement in pain, function and activities after 24 weeks than patients with high baseline pain scores.

Running-Related Achilles Tendon Injury: A Prospective Biomechanical Study in Recreational Runners

There are relatively few running studies that have attempted to prospectively identify biomechanical risk factors associated with Achilles tendon (AT) injuries. Therefore, the aim was to prospectively determine potential running biomechanical risk factors associated with the development of AT injuries in recreational, healthy runners. At study entry, 108 participants completed a set of questionnaires. They underwent an analysis of their running biomechanics at self-selected running speed. The incidence of AT running-related injuries (RRI) was assessed after 1-year using a weekly questionnaire standardized for RRI. Potential biomechanical risk factors for the development of AT RRI injury were identified using multivariable logistic regression. Of the 103 participants, 25% of the sample (15 males and 11 females) reported an AT RRI on the right lower limb during the 1-year evaluation period. A more flexed knee at initial contact (odds ratio = 1.146, P = .034) and at the midstance phase (odds ratio = 1.143, P = .037) were significant predictors for developing AT RRI. The results suggested that a 1-degree increase in knee flexion at initial contact and midstance was associated with a 15% increase in the risk of an AT RRI, thus causing a limitation of training or a stoppage of running in runners.

Lower motor unit discharge rates in gastrocnemius lateralis, but not in gastrocnemius medialis or soleus, in runners with Achilles tendinopathy: a pilot study

OBJECTIVES

Deficits in muscle performance could be a consequence of a reduced ability of a motor neuron to increase the rate in which it discharges. This study aimed to investigate motor unit (MU) discharge properties of each triceps surae muscle (TS) and TS torque steadiness during submaximal intensities in runners with Achilles tendinopathy (AT).

METHODS

We recruited runners with (n = 12) and without (n = 13) mid-portion AT. MU discharge rate was analysed for each of the TS muscles, using high-density surface electromyography during 10 and 20% isometric plantar flexor contractions.

RESULTS

MU mean discharge rate was lower in the gastrocnemius lateralis (GL) in AT compared to controls. In AT, GL MU mean discharge rate did not increase as torque increased from 10% peak torque, 8.24 pps (95% CI 7.08 to 9.41) to 20%, 8.52 pps (7.41 to 9.63, p = 0.540); however, in controls, MU discharge rate increased as torque increased from 10%, 8.39 pps (7.25-9.53) to 20%, 10.07 pps (8.89-11.25, p < 0.001). There were no between-group difference in gastrocnemius medialis (GM) or soleus (SOL) MU discharge rates. We found no between-group differences in coefficient of variation of MU discharge rate in any of the TS muscles nor in TS torque steadiness.

CONCLUSION

Our data demonstrate that runners with AT may have a lower neural drive to GL, failing to increase MU discharge rate to adjust for the increase in torque demand. Further research is needed to understand how interventions focussing on increasing neural drive to GL would affect muscle function in runners with AT.

The effect of combined Action Observation Therapy with eccentric exercises in the treatment of mid-portion Achilles-tendinopathy: a feasibility pilot randomised controlled trial

BACKGROUND

Mid-portion Achilles Tendinopathy (AT) is a common musculoskeletal condition with varying rehabilitation success rates. Despite the prevalence of this condition, a considerable proportion of individuals experience persisting pain and functional deficits. Current treatment approaches bias the biomedical model which emphasises physically treating and loading the tendon. Overall, there is a lack of consideration for the central nervous system that is commonly implicated in chronic injuries. The aim of this pilot study was to explore the feasibility of combining Action Observation Therapy (AOT), a treatment technique which targets central changes and influences motor learning, with eccentric exercises in the treatment of mid-portion AT. AOT involves the observation of movements and is commonly followed by the physical performance of these same movements.

METHODOLOGY

This was a double-blinded randomised controlled pilot feasibility study. All participants underwent the 12-week Alfredson eccentric training protocol. The intervention group watched videos of the exercises prior to performing these exercises, whilst the control group watched nature videos before performing the same exercises. Study feasibility was the primary outcome measure, with the Victorian Institute of Sports Assessment- Achilles (VISA-A) selected as the primary clinical outcome measure.

RESULTS

Thirty participants were recruited, reflecting a 75% eligibility rate and 100% of eligible participants enrolled in the study. The retention rate at week 12 was 80%. At week six the mean VISA-A score improved by 18.1 (95% CI 10.2-26.0) in the intervention group and 7.7 (95% CI 0.3-14.9) in the control group, and 75% and 33% of participants in the intervention and control group respectively exceeded the minimal clinically important difference (MCID). At week 12 the mean VISA-A score from baseline improved by 22.25 (95% CI 12.52-31.98) in the intervention group and 16.5-(95% CI 8.47-24.53) in the control group, equating to 75% and 58% in each group respectively exceeding the MCID.

CONCLUSION

The positive feasibility outcomes and exploratory data from the clinical outcome measures suggest that a larger scaled RCT is warranted to further investigate the impact of AOT in the rehabilitation of mid-portion AT. Trial registration ISRCTN58161116, first registered on the 23/12/2020.

Intra- and Inter-Rater Reliability of Processing Ultrasound Tissue Characterization Scans in Midportion Achilles Tendinopathy

Purpose

Ultrasound tissue characterization (UTC) is used to visualize and quantify the Achilles tendon structure. We investigated the intra-rater and inter-rater reliability of UTC for quantifying the midportion tendon structure and the area of maximum degeneration (AoMD) in military personnel with midportion Achilles tendinopathy.

Method

UTC scans of 50 patients (16-60 years) were processed twice by rater 1 and once by rater 2. First, the midportion tendon structure was quantified and subsequently the AoMD. The intraclass correlation coefficient (ICC) was calculated for echo-types I, II, III, IV, aligned fibrillar structure (echo-types I + II), and disorganized tendon structure (echo-types III + IV).

Results

For midportion tendon structure, all ICC values were excellent for intra-rater reliability (range: 0.97 to 0.99) and inter-rater reliability (range: 0.98 to 0.99). Regarding the AoMD, intra-rater reliability showed excellent ICC values for all echo-types (range: 0.94 to 0.98) except for echo-type II (0.85). Inter-rater reliability showed excellent ICC values for all echo-types (range: 0.92 to 0.98).

Conclusion

Processing of UTC scans is highly reliable in quantifying the midportion Achilles tendon structure and the AoMD.

Bibliometric Study of Exercise and Tendinopathy Research from 2001 to 2020

Background

Tendinopathy is a tendon disease that often occurs in athletes. Many studies have revealed that exercise therapy is beneficial for the nonoperative management of tendinopathy. However, the general aspect bibliometric analysis of this global research topic associated with exercise and tendinopathy is lacking. The present study aimed to make a bibliometric analysis of worldwide development tendency and research hotspots in exercise and tendinopathy research from 2001 to 2020.

Material/Methods

Using the Web of Science, articles and reviews published between 2001 and 2020 were retrieved from the Science Citation Index Expanded database. CiteSpace was used to analyze the relationship among publications, countries, institutions, journals, authors, references, and keywords.

Results

In total, 857 articles were found in this study. Over the past 20 years, there was a marked increase in the number of publications. A total of 194 different scholarly journals were dedicated to the categories Sport Sciences, Orthopedics, and Rehabilitation. The USA and La Trobe University were the most prolific country and institution, respectively. The British Journal of Sports Medicine was the prominent journal for research on exercise and tendinopathy and had the most publications. The analysis of keywords showed that rehabilitation, rotator cuff tendinopathy, stiffness, and disability of individuals with tendinopathy had become the research focus in this field.

Conclusions

Bibliometric analysis provides a historical and scientific perspective on exercise and tendinopathy research, providing relevant researchers, funding agencies, and policymakers with valuable information to explore the current research status, hotspots, and new directions for future research.

Are static foot posture and ankle dorsiflexion range of motion associated with Achilles tendinopathy? A cross-sectional study

BACKGROUND

Subtalar hyperpronation and ankle dorsiflexion restriction have been theoretically associated with Achilles tendinopathy (AT). However, evidence to support these associations is lacking.

OBJECTIVES

To compare foot alignment and ankle dorsiflexion range of motion (ROM) between the symptomatic and non-symptomatic limbs of individuals with unilateral AT. And to verify whether differences exist between individuals with symptomatic pronated feet and individuals with symptomatic neutral/supinated feet in terms of tendon pain, structure, and symptom severity.

METHODS

Sixty-three participants with unilateral AT underwent a bilateral evaluation of pain during tendon palpation, symptom severity, tendon thickening, tendon neovascularization, ankle dorsiflexion ROM, and foot posture alignment [foot posture index (FPI), navicular drop, navicular drift, and longitudinal arch angle (LAA)]. Side and group comparisons were made using t-tests and correlations were evaluated using the Pearson test.

RESULTS

There were no differences between the symptomatic and non-symptomatic limbs regarding foot posture alignment. Specifically, non-significant negligible differences were observed between limbs regarding FPI [mean difference (MD)=-0.23; 95% confidence interval (CI)=-0.70, 0.25), navicular drop (MD=0.58 mm; 95%CI=-0.25, 1.43), navicular drift (MD=0.16 mm; 95%CI=-0.77, 1.09), and LAA (MD=0.30º; 95%CI=-1.74, 2.34). There was no difference between limbs regarding ankle dorsiflexion ROM. However, lower ankle dorsiflexion was associated with worse symptom severity (r = 0.223). Finally, no difference was observed between individuals with symptomatic pronated feet and individuals with symptomatic neutral/supinated feet in terms of tendon pain or structure.

CONCLUSIONS

Static foot alignment measures do not seem to be clinically relevant in patients with AT. Smaller ankle dorsiflexion ROM, however, was associated with greater symptom severity in this population.

Management of recent onset tendon-related pain in a primary contact setting: A survey of practice

BACKGROUND

Tendon-related pain is a common and debilitating condition that affects a wide range of people. To inform future research, it is important to understand healthcare professional's current practice.

OBJECTIVES

To describe the practice of First Contact Practitioners (FCPs) and Other Clinicians (OCs) for recent onset tendon pain in a primary contact setting. The secondary aim was to understand if practice differed between the locations of pain.

DESIGN

Cross-sectional online survey METHOD: The online survey asked for responses relating to one scenario of shoulder pain and one of Achilles pain. Except location of pain, the scenarios were identical. Responses were collected over a four-week period to December 2020. The Chi-Square test was used to analyse the difference in proportion of responses between FCPs and OCs, and between locations of pain.

RESULTS

118 responses were received. Rotator Cuff Related Shoulder Pain (RCRSP) was preferred by 64/118 (54.2%) for the shoulder scenario. Achilles tendinopathy was the preferred term by 86/103 (83.5%) for the Achilles. FCPs were more likely to advise NSAIDs for both shoulder (p = 0.006) and Achilles (p = 0.046) scenarios than OCs. Amended duties were more likely to be advised for manual workers for the shoulder scenario compared to Achilles (p = <0.0001).

CONCLUSION

There were similarities in the management of recent onset tendon-related pain; the majority of respondents recommended against further investigations, steroid injections, and recommended exercise. Understanding whether these approaches are clinically effective requires further investigation.

Impact of chronic Achilles tendinopathy on health-related quality of life, work performance, healthcare utilisation and costs

Objectives

To evaluate the impact of Achilles tendinopathy (AT) on quality of life (QoL), work performance, healthcare utilisation and costs in adults with conservatively treated chronic midportion AT.

Methods

This cross-sectional survey-based study included 80 patients and took place in a sports medicine department of a large regional hospital in the Netherlands. Data were collected before any intervention was given. Primary outcome was the EuroQol questionnaire (EQ-5D). The EQ-5D expresses the percentage of moderate/major problems on the domains self-care, anxiety/depression, mobility, usual activities and pain/discomfort. Secondary outcomes were the number of previous healthcare visits, work performance during the period of symptoms and estimated annual direct medical and indirect costs per patient as a result of AT.

Results

All 80 patients completed the questionnaires. The EQ-5D scores were low for the domains self-care (1%) and anxiety/depression (20%), and high for the domains mobility (66%), usual activities (50%) and pain/discomfort (89%). Patients with AT mainly reported an impact on work productivity (38%). Work absenteeism due to AT was present in 9%. The total median (IQR) number of annual healthcare visits was 9 (3-11). The total mean (SD) estimated annual costs were €840 (1420) per patient with AT (mean (SD) US$991 (1675)).

Conclusions

This study shows the large impact of AT on QoL and work productivity. This study also provides new information about the socioeconomic impact of AT, which emphasises that this common and longstanding disease causes substantial costs. These findings stress the need for optimised treatment and improved preventive interventions for AT.

Trial registration number

NCT02996409.

Thermographic assessment of the immediate and short term-effects of blood flow restriction exercise on Achilles tendon skin temperature

OBJECTIVES

To determine the thermal patterning of the Achilles tendon following bodyweight resistance exercise with and without blood-flow restriction (BFR).

DESIGN

Cross-sectional.

SETTING

Research laboratory.

PARTICIPANTS

Twelve asymptomatic recreational runners (Age: 37 ± 10, Height: 169 ± 20, Mass: 73.8 ± 13.4).

MAIN OUTCOME MEASURES

Thermograms were taken pre and post exercise with and without a BFR cuff on separate legs. BFR cuff pressure was set at 80% maximal arterial occlusion pressure determined using doppler via the tibial artery. Linear mixed-effects models were used to assess the effect of BFR and time post-exercise on skin-temperature (Tskin).

RESULTS

A lower Tskin was seen following BFR exercise at the tendon insertion (P = 0.002), but not at the free tendon (P = 0.234), or the musculotendinous junction (P = 0.933). A significant effect of time upon changes in Tskin was observed in both BFR and non-BFR groups (P = 0.002). No interaction of time and BFR were observed on changes in Tskin (P = 0.726).

CONCLUSION

Region specific changes in Tskin were found, with greater and longer reductions observed at the insertion of the Achilles following BFR exercise before returning to baseline. These findings could have implications for the programming of BFR exercise on tendon health. Future research should observe for differences between symptomatic and healthy tendons.

Which treatment is most effective for patients with Achilles tendinopathy? A living systematic review with network meta-analysis of 29 randomised controlled trials

OBJECTIVE

To provide a consistently updated overview of the comparative effectiveness of treatments for Achilles tendinopathy.

DESIGN

Living systematic review and network meta-analysis.

DATA SOURCES

Multiple databases including grey literature sources were searched up to February 2019.

STUDY ELIGIBILITY CRITERIA

Randomised controlled trials examining the effectiveness of any treatment in patients with both insertional and/or midportion Achilles tendinopathy. We excluded trials with 10 or fewer participants per treatment arm or trials investigating tendon ruptures.

DATA EXTRACTION AND SYNTHESIS

Reviewers independently extracted data and assessed the risk of bias. We used the Grading of Recommendations Assessment, Development and Evaluation to appraise the certainty of evidence.

PRIMARY OUTCOME MEASURE

The validated patient-reported Victorian Institute of Sport Assessment-Achilles questionnaire.

RESULTS

29 trials investigating 42 different treatments were included. 22 trials (76%) were at high risk of bias and 7 (24%) had some concerns. Most trials included patients with midportion tendinopathy (86%). Any treatment class seemed superior to wait-and-see for midportion Achilles tendinopathy at 3 months (very low to low certainty of evidence). At 12 months, exercise therapy, exercise+injection therapy and exercise+night splint therapy were all comparable with injection therapy for midportion tendinopathy (very low to low certainty). No network meta-analysis could be performed for insertional Achilles tendinopathy.

SUMMARY/CONCLUSION

In our living network meta-analysis no trials were at low risk of bias and there was large uncertainty in the comparative estimates. For midportion Achilles tendinopathy, wait-and-see is not recommended as all active treatments seemed superior at 3-month follow-up. There seems to be no clinically relevant difference in effectiveness between different active treatments at either 3-month or 12-month follow-up. As exercise therapy is easy to prescribe, can be of low cost and has few harms, clinicians could consider starting treatment with a calf-muscle exercise programme.

PROSPERO REGISTRATION NUMBER

CRD42018086467.

Stiffness of the Gastrocnemius-Achilles Tendon Complex Between Amateur Basketball Players and the Non-athletic General Population

Muscle and tendon stiffness are related to sports performance, tendinopathy, and tendon degeneration. However, the effects of habitual loading on muscle and tendon mechanical properties are unclear. Using amateur basketball players as examples, we investigated the effects of mechanical loading on the stiffness of the gastrocnemius–Achilles tendon (AT) complex in non-dominant and dominant lower limbs. Then, we evaluated the correlation between gastrocnemius and AT stiffness. Forty participants (20 amateur basketball players; 20 normal non-athletic persons) were recruited for this study. Stiffness of the gastrocnemius–AT complex was assessed using MyotonPRO at neutral position and 10° dorsiflexion of the ankle joint in participants from amateur basketball players and the non-athletic general population. Our results showed a greater stiffness of the gastrocnemius–AT complex in amateur basketball players than that in healthy non-athletic subjects at neutral position and 10° dorsiflexion of the ankle joint (P < 0.05). No significant difference in stiffness was found between the non-dominant and dominant lower limbs either in amateur basketball players or in generally healthy subjects (P > 0.05). A significant positive correlation was obtained between stiffness of the AT and medial gastrocnemius (MG) in amateur basketball players (neutral position: r = 0.726 and P = 0.001; dorsiflexion 10°: r = 0.687 and P = 0.001). The amateur basketball players exhibit significantly higher stiffness value in Achilles and gastrocnemius. This is possibly caused by repeated training effects. The symmetric stiffness of the AT and gastrocnemius exists both in amateur basketball players and generally healthy subjects. A significant correlation between the AT and the MG was found in amateur basketball players.

Effectiveness of a high volume injection as treatment for chronic Achilles tendinopathy: randomised controlled trial

OBJECTIVE

To study whether a high volume injection without corticosteroids improves clinical outcome in addition to usual care for adults with chronic midportion Achilles tendinopathy.

DESIGN

Patient and assessor blinded, placebo controlled randomised clinical trial.

SETTING

Sports medicine department of a large district general hospital, the Netherlands.

PARTICIPANTS

80 adults (aged 18-70 years) with clinically diagnosed chronic midportion Achilles tendinopathy and neovascularisation on ultrasonography. 39 were randomised to a high volume injection without corticosteroids and 41 to placebo.

INTERVENTIONS

Participants were instructed to perform an exercise programme for 24 weeks (usual care) combined with one 50 mL high volume injection of saline and lidocaine (intervention group) or one 2 mL placebo injection of saline and lidocaine (placebo group) at baseline.

MAIN OUTCOME MEASURES

Primary outcome was pain and function assessed using the validated Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire at 24 weeks (analysed using a generalised estimation equations model). Secondary outcomes were patient satisfaction, return to sport, degree of ultrasonographic Doppler flow, visual analogue scale on 10 hop test, power and flexibility of the gastrocnemius and soleus muscles, pain detect questionnaire for neuropathic pain, and pain coping inventory. Participants were evaluated at baseline and at 2, 6, 12, and 24 weeks.

RESULTS

Only one participant (1%) was lost to follow-up. The estimated mean VISA-A score improved significantly, from 40.4 (95% confidence interval 32.0 to 48.7) at baseline to 59.1 (50.4 to 67.8) at 24 weeks in the high volume injection group and from 36.9 (27.1 to 46.8) to 58.5 (47.9 to 69.1) in the placebo group. The VISA-A score over time did not differ between the groups (adjusted between group difference at 24 weeks 0.5 points, 95% confidence interval -17.8 to 18.8). No significant between group differences were found for patient satisfaction (21/37 (57%) v 19/39 (49%) patients, P=0.50) and return to desired sport (15/29 (52%) v 19/31 (61%) patients active in sports, P=0.65) at 24 weeks. None of the other secondary outcomes differed between the two groups.

CONCLUSIONS

A high volume injection without corticosteroids in addition to usual care is not effective for symptom reduction in patients with chronic midportion Achilles tendinopathy. On the basis of our findings, we cannot recommend the use of a high volume injection in this patient group.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02996409.

How many runners with new-onset Achilles tendinopathy develop persisting symptoms? A large prospective cohort study

BACKGROUND

Achilles tendinopathy (AT) occurs in half of the elite runners. AT is a difficult-to-treat tendon disease, which may progress from new onset to a chronic state. It is unknown how many runners with new-onset AT develop persisting symptoms and which prognostic factors are associated with this course.

OBJECTIVE

To describe how many runners develop persisting symptoms 1 year after onset of reactive AT.

STUDY DESIGN

Prospective cohort study.

METHODS

Runners registering for a Dutch running event (5-42.2 km) were eligible for inclusion. Runners reporting new-onset AT between registration for the running event and 1 month after received a 1-year follow-up questionnaire. The 1-year follow-up questionnaire inquired about persisting symptoms (yes/no), running activity, and metabolic disorders. We calculated the percentage of runners with persisting symptoms and performed a multivariable logistic regression analysis to study the association between potential prognostic factors and persisting symptoms.

RESULTS

Of 1929 participants, 100 runners (5%) reported new-onset AT. A total of 62 runners (62%) filled in the 1-year follow-up questionnaire. Persisting symptoms were reported by 20 runners (32%). A higher running distance per week before new-onset AT was associated with a lower risk of developing persisting symptoms (odds ratio (OR): 0.9, 95% confidence interval (CI): [0.9;1.0]). There was a positive trend toward an association between metabolic disorders and persisting symptoms (OR: 5.7, 95% CI: [0.9;36.2]).

CONCLUSION

One third of runners develop persisting symptoms 1 year after new-onset AT. Interestingly, a higher running distance per week before new-onset AT potentially lowers the risk of developing persisting symptoms.