See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/224915221 Achilles Tendinopathy in Club Runners Article in International Journal of Sports Medicine · May 2012 DOI: 10.1055/s-0032-1313785 · Source: PubMed CITATIONS READS 22 668 6 authors, including: Zainulabdin Shaikh Dylan Morrissey Somaiya Vidyavihar Queen Mary, University of London 14 PUBLICATIONS 104 CITATIONS 248 PUBLICATIONS 4,417 CITATIONS SEE PROFILE SEE PROFILE Angelo Del Buono Nicola Maffulli Azienda Unità Sanitaria Locale Parma Università degli Studi di Salerno 140 PUBLICATIONS 4,032 CITATIONS 1,899 PUBLICATIONS 66,796 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: EFAS Score View project At present I am working on clinical studies on patients after minimally invasive arthroplasty of the gip View project All content following this page was uploaded by Nicola Maffulli on 04 June 2014. The user has requested enhancement of the downloaded file. IJSM/2377/16.1.2012/Macmillan IJSM/2377/16.1.2012/Macmillan Orthopedics & Biomechanics Achilles Tendinopathy in Club Runners Authors Affiliations Key words ▶ ultrasound ● ▶ athletes ● ▶ tendons ● ▶ symptoms ● Z. Shaikh1, M. Perry1, D. Morrissey1, M. Ahmad2, A. Del Buono3, N. Maffulli1 1 Barts and The London School of Medicine and Dentistry, Centre for Sports and Exercise Medicine, United Kingdom Barts and The London School of Medicine and Dentistry, Radiology, Queen Mary University of London, United Kingdom 3 University Campus Bio Medico, Department of Orthopaedic and Trauma Surgery, Rome, Italy 2 Abstract ▼ Ultrasound (US) changes within the Achilles tendon are present in asymptomatic Achilles individuals. We assessed the association of US signs with symptoms of Achilles tendinopathy in a study group of club level running athletes and in a control group of athletes training at least 2 times per week. The Achilles tendon was assessed in its entirety on longitudinal US scans, at the musculotendinous junction (MTJ), the calcaneal insertion site, and at a midtendon point. 25 middle distance runners, 19 males and 6 females, aged from 18 to 58, were enrolled in each group. When compared to control ath- Introduction ▼ accepted after revision November 24, 2011 Bibliography DOI http://dx.doi.org/ 10.1055/s-0031-1299701 Int J Sports Med 2012; 33: 1–5 © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Prof. Nicola Maffulli Queen Mary University of London Centre for Sports and Exercise Medicine 275 Bancroft Road E1 4DG London United Kingdom Tel.: +44/20/8223 8839 Fax: +44/20/8223 8930 n.maffulli@qmul.ac.uk Tendinopathy of the main body of the Achilles tendon is a common overuse injury [10] in runners and jumpers [1, 2, 37]. Classically, discomfort occurs at the beginning and immediately after exercise, and improves during activity [14]. Over time, pain, swelling and stiffness may limit training performance, and induce athletes to prematurely abandon the sport career [10, 13, 24, 40]. In elite track and field, about 50 % of middle and long distance veteran runners complain of symptoms of Achilles tendinopathy in their lifetime, with higher incidence of ruptures in sprinters [16–19]. The incidence of Achilles tendinopathy in elite, development and club level tri-athletes is comparable [39], but little attention has been paid on club level activities [21]. With MRI and clinical examination, ultrasonography (US) is a suitable validated tool for diagnosis of Achilles tendinopathy [3, 6, 35]. Focal thickening, blurred paratenon margins, hypoechoic areas and tendon neovascularization are the most common findings [4, 8, 24, 31, 32]. letes, club level runners presented significantly increased tendon thickness (p = 0.046) at the musculo-tendinous junction, and increased tendon thickness, with no statistical significance, at the other landmarks points. Although club level runners were significantly more symptomatic and predisposed to develop signs of tendinopathy than control athletes (p = < 0.001), ultrasound abnormalities were not significantly associated with local symptoms complained at the US investigation time. Prospective studies on asymptomatic athletes are needed to define the predictive value of US signs of Achilles tendinopathy in the development of symptoms in the long-term. Since symptoms of Achilles tendinopathy occur regardless of US scans findings, the role of US imaging assessment of patients with asymptomatic Achilles tendon changes is still unclear [22– 24]. Up to 90 % of tendons with US evidence of tendinopathic changes are asymptomatic [15, 20], and similar pathological features may be found in asymptomatic and symptomatic tendons [38] as expression of a continuum of a failed healing response [24, 38]. However, symptoms may be independent from the presence of intratendinous changes. Tendinopathic changes may become symptomatic over time, and US changes should be better investigated in subjects with asymptomatic Achilles tendon changes to ascertain whether targeted interventions may prevent further changes and decrease the rate of onset of symptoms [25, 30]. This study assessed the prevalence of ultrasound signs and symptoms of Achilles tendinopathy in club level running athletes, and describes the association between US and clinical findings. ■ Proof copy for correction only. All forms of publication, duplication or distribution prohibited under copyright law. ■ Shaikh Z et al. Achilles Tendinopathy in Club Runners. Int J Sports Med 2012; 33: 1–5 1 2 Orthopedics & Biomechanics Materials and Methods ▼ This study was approved by the Institutional Review Board and Ethical Committee of the Queen Mary University of London and was in agreement with the ethical standards of the journal [12]. All the athletes, recruited from London Heathside Athletics Club, gave their written informed consent to participate in the study. Athletes training at least 2 times per week were included in the control group. The 2 groups were matched for sex and age. Anthropometric data (height, weight and BMI) were measured, and information on leg dominance, age and gender were collected. A self-administered questionnaire provided further information on type of sport, average number of training sessions per week, number of years of training at that level, occurrence and duration of symptoms of Achilles tendinopathy in the past and at present time, and missing time from sport activities. The same questionnaire was administered to study and control athletes, except for questions pertaining to the type of club activity, referred only to the study group. Symptoms of Achilles tendinopathy were listed as pain, tenderness, and stiffness [14]. Subjects were also asked whether symptoms were present at the time of them filling in the questionnaire investigation, in the last month, in the last 3 months, or at any time during their life. US imaging All US investigations were performed by a single experienced musculoskeletal radiologist unaware of the questionnaire information. High-resolution 3–12 MHz linear transducers (Volusoni, GE Medical Systems, UK) and Achilles tendon setting were used to optimize ultrasound assessments. With the subject prone, the heels overhanging couch, and the ankles flexed to 90 °, each Achilles tendon was entirely assessed in the longitudinal plane. To avoid potential artifacts, the transducer was positioned perpendicular to the tendon fibres. The Achilles tendon thickness, measured in centimeters, was entirely assessed along its length. To exactly repeat the measures, measurement were carried out on longitudinal scans, at the musculotendinous junction (MTJ), the calcaneal insertion site (CI), and at a midtendon point. Tendon abnormalities were classified according to the grey-scale grading system. To assess tendon vascularity, Power Doppler (PD) settings were standardised with a gain of 68 dB, sensitivity of 8 cm/s, and pulse repetition frequency of 800–1 000 Hz. On longitudinal scans, tendon abnormalities were classified as focal thickening, hypoechoic areas, paratenon blurring and neovascularization. Tendons images were anonymized, scanned, saved, and successively examined by a second radiologist in a blind fashion. The measurements were repeated the same day. The coefficient of variation (CV) of the measurement obtained at the 3 landmark points was calculated. IJSM/2377/16.1.2012/Macmillan IJSM/2377/16.1.2012/Macmillan chi-square test was used to assess the relationship between symptoms and US findings. Confidence intervals of 95 % were calculated. A significance level of 0.05 was used. SPSS version 17.0 was used to analyze the data. Based on the result of a previous pilot study assessing Achilles tendinopathy in elite gymnasts, a total sample size of 98 tendons (49 tendons per group) was required to obtain statistical significance at .05 level with a power of 80 % power. We therefore enrolled 50 tendons per group in this study. Results ▼ 25 middle distance runners, 19 males and 6 females, aged from 18 to 58, were enrolled in each group. Both the Achilles tendons were assessed in each subject. Anthropometric data for both ▶ Table 1. groups and inter-group differences are shown in ● Ultrasound tendon thickness measurements ▶ Table 2). EstiICC and LOA showed good intra-test reliability (● mated marginal mean (EMM) and standard error (SE) values of tendon thickness measurements were calculated for each ten▶ Table 3). don landmark (● The distribution of the tendon thickness values measured at the ▶ Fig. 1). At the muscmusculo-tendinous junction was normal (● ulo-tendinous junction, club level runners presented significantly increased tendon thickness (p = 0.046) than control athletes ▶ Table 3; ● ▶ Fig. 2). Regarding the other landmarks points, club (● level runners also had increased tendon thickness, but no statistical Table 1 Anthropometric data of athlete and control groups. Variable Group t-test p-value Mean (SD) (equal variances not assumed) age (years) height (m) weight (kg) BMI gender; male:female Athlete 34.2 (13.0) 1.74 (0.08) 69.68 (9.39) 22.82 (1.71) 38:12 Control 31.3 (15.1) 1.68 (0.08) 66.16 (15.39) 23.36 (4.10) 38:12 0.303 < 0.001 0.171 0.393 Table 2 Results of intra-reliability tests using intraclass correlation coefficients and limits of agreement. Point along tendon ICC LOA longitudinal CI longitudinal midtendon longitudinal MTJ 0.964 0.718 0.680 0.04 0.05 0.13 Statistical analysis Intra-class correlation coefficients (ICCs) [5] and limits of agreement (LOA) [5] were used for intra-reliability statistical analysis. Continuous data were firstly assessed to establish distribution, by observing frequency histograms, and parametric nature. Independent t-tests and chi-square tests were used for comparison of continuous (age, height and weight) and categorical (symptoms) variables between the 2 groups. Univariate analysis of variance (ANOVA) for repeated measures was used to assess for significant changes in the mean thickness of the tendon. The Table 3 Estimated marginal means (EMM) for tendon thickness at insertion, mid-point and musculotendinous junction. Variable longitudinal CI longitudinal midtendon longitudinal MTJ Athlete EMM 0.374 0.489 0.453 SE 0.011 0.030 0.016 Control EMM 0.361 0.455 0.414 SE 0.011 0.020 0.016 P-value 0.434 0.247 0.046 Adjusted for height, with height = 1.71 m ■ Proof copy for correction only. All forms of publication, duplication or distribution prohibited under copyright law. ■ Shaikh Z et al. Achilles Tendinopathy in Club Runners. Int J Sports Med 2012; 33: 1–5 IJSM/2377/16.1.2012/Macmillan IJSM/2377/16.1.2012/Macmillan Orthopedics & Biomechanics significance was found. The CV of the 3 tendon measurements, with an average thickness of 0.22 mm for the club level runners and 0.17 mm for the control group, did not show a statistically signifi▶ Fig. 3). cant inter-group difference (p = 0.091) (● Symptoms of achilles tendinopathy Club middle distance runners were significantly more symptomatic than control those for all categories of symptoms reported ▶ Table 4). in the questionnaire (● Ultrasound signs of achilles tendinopathy A tendon was classified as abnormal if at least one of the above cited abnormalities was found at ultrasound assessment. Signs of tendinopathy were detected in 18 of 50 (36 %) tendons for the club level runners, and in 2 of 50 (4 %) tendons for the control group (p = < 0.001). At the time of the US scan, 8 club level runners (8 tendons), all with changes at US, were symptomatic. No control subjects reported any symptoms. On the other hand, all the 16 club runners (20 tendons) with US changes had reported some symptoms in the relevant Achilles tendon in the last month. 12 10 Frequency 8 6 4 Discussion ▼ 2 0 0.200 0.400 0.600 0.800 Longitudinal myotendinous junction Fig. 1 Normal distribution of measures at longitudinal musculotendinous junction. MTJ Thickness Thickness measurement (cm) 0.48 0.46 0.44 0.42 0.40 0.38 0.36 Long MTJ Control Athletes Fig. 2 Thickness of musculotendinous junction in athletes compared with controls. Longitudinal CV Measurements 0.25 CV Value 0.20 0.15 0.10 0.05 0 Longitudinal CV Control Athlete Fig. 3 Coefficient of Variation (CV) of thickness measurements in athlete compared with control group. Achilles tendinopathy influences performance and training in elite track athletes, but little is known for middle distance runners active at club levels. This study shows significantly higher incidence of symptoms of Achilles tendinopathy and ultrasound abnormalities in club level athletes than in control subjects. In addition, club level athletes had greater tendon thickness than control, those with statistical significance only at the muscletendon junction. Nicol et al. [30], in a comparative analysis of active and inactive subjects, reported US evidence of fusiform thickening in 14 (5.6 %) of 252 Achilles tendons examined, all in the active group. Increased thickness is a sign of tendinopathy or an overuse response to repeated loads and stresses [41]. Hypoechoic lesions were also found in 41 of 50 tendons (84 %) of patients with history of previous Achilles tendon pain, particularly in those most active. Malliaras et al., in a study reporting on greyscale US changes in tendinopathy, stated that tendons containing a hypoechoic region are more likely to be painful, and contain Doppler flow more than diffusely thickened tendons [26]. Even though US hypoechoic changes are known to be markedly abnormal areas which contain an increased amount of glicosoaminoglicans [29], the relationship between US, histopathological and clinical features is still unclear. In the present study, subjects had mostly been symptomatic in the last 3 months or in the long-term, and only few athletes reported symptoms at the time of the US examination. 3 out of 4 athletes (75 %) symptomatic at the moment of US examination, and 4 of 5 subjects with symptoms over the last month had ultrasound signs of tendinopathy. Although US is more sensitive and specific in detecting signs of Achilles tendinopathy in subjects who complain of long-time symptoms [24, 27], the relatively low number of subjects does not allow to extend our findings to all club runners. The relationship between occurrence of US changes and subjects’ symptoms is not clear [28, 34]. We found positive ultrasound signs in 25 % of asymptomatic athletes. Nicol et al. [30] found hypoechoic regions in 88 of 149 tendons (59 %) of asymptomatic athletes. Hypoechoic regions were also found in 41 of 50 tendons (84 %) of patients with history of previous Achilles tendon pain, particularly in those most active. It is possible that our asymptomatic athletes with positive US findings have been assessed in a pre-symptomatic phase, as soon as these US changes, present for a long time, could be not relevant from a clinical standpoint. Fredberg and Bolvig [9] reported ■ Proof copy for correction only. All forms of publication, duplication or distribution prohibited under copyright law. ■ Shaikh Z et al. Achilles Tendinopathy in Club Runners. Int J Sports Med 2012; 33: 1–5 3 4 Orthopedics & Biomechanics IJSM/2377/16.1.2012/Macmillan IJSM/2377/16.1.2012/Macmillan Table 4 Achilles tendinopathy symptoms in the athlete group. Symptoms now ever pain in last month continuing pain for 3 months on/off pain for 3 months Athlete % with symptoms 8 42 20 12 30 Chi-square value 4.167 23.310 11.111 6.383 17.647 US tendinopathic changes in 11 of 96 Achilles and patellar tendons of asymptomatic soccer players, 45 % of whom (5 tendons) developed symptoms in the long-term. On the other hand, Ohberg et al. [33], in a 4-year follow-up study, found normalised ultrasound tendon structure and reduced thickness in 19 of 26 painful Achilles undergoing eccentric training. The subjects with increased risk to develop symptoms could preventively undergo strategies of management, but the scientific evidence supporting that special activities or exercises may prevent further development of degenerative tendon changes and symptoms in asymptomatic athletes is scant. Prophylactic eccentric training and stretching programs reduce the risk of developing US abnormalities in patients with symptoms of patellar tendinopathy, but the risk of tendon injury is increased [10]. Also, in asymptomatic football players with US abnormal Achilles tendons, prophylactic eccentric training and stretching have no effect in reducing neither the risk of development of US abnormalities nor the risk of occurrence of tendon injury [10]. Further investigations are needed to define the factors involved in the long-term development of symptoms in subjects with US signs of Achilles tendinopathy. The BMI of athletes and controls were comparable, and statistically not different. It has been shown that adiposity and its distribution may exert an influence on the rate of development of patellar tendinopathy in athletes [7, 11]. We are not aware of any studies ascertaining the possible association of height alone and Achilles tendinopathy. While we do not question that the athletes were statistically significantly taller than the controls, we doubt that this difference bears any clinical relevance, in the presence of a similar BMI. This study presents several weaknesses. Firstly, we enrolled the minimum sample size to obtain statistically significant findings, and the number of subjects is relatively small. There was evidence of a statistically significant association of US signs with symptoms only in subjects with symptoms in the last month, not in those who were symptomatic on the day of US examination. This result does not arise from the ability of the primary investigator to identify US signs of pathology, and, reviewing the scans, the findings were confirmed. Because the risk of developing Achilles tendinopathy is related to the type of sport activity [36, 38], this is a potential confounding factor of the present study. However, all our athletes were track runners. The wide range of age of the athletes could have influenced results, with the older athletes more likely to become symptomatic for Achilles tendinopathy. To avoid this bias, in our study, the 2 groups were matched for age. Since the athletes were examined only once, we are not aware of the evolution of symptoms and US changes. Strength of the study is that 2 US investigations were performed for each subject by a musculoskeletal radiologist, unaware of the clinical and questionnaire information, and imaging findings were reviewed by a second blinded investigator. Control % with symptoms 0 2 0 0 0 P-value Chi-square value 4.167 23.310 11.111 6.383 17.647 0.041 < 0.001 0.001 0.012 < 0.001 Conclusion ▼ Compared to control athletes, club level runners are more prone to develop symptoms and US signs of Achilles tendinopathy, with increased thickness of the muscle tendon junction. Prospective studies on asymptomatic athletes are needed to define the predictive value of US signs of Achilles tendinopathy in the development of symptoms in the long-term. References 1 Alfredson H. Chronic midportion Achilles tendinopathy: an update on research and treatment. Clin Sports Med 2003; 22: 727–741 2 Ames PR, Longo UG, Denaro V, Maffulli N. Achilles tendon problems: not just an orthopaedic issue. Disabil Rehabil 2008; 30: 1646–1650 3 Astrom M, Gentz CF, Nilsson P, Rausing A, Sjoberg S, Westlin N. Imaging in chronic Achilles tendinopathy: a comparison of ultrasonography, magnetic resonance imaging and surgical findings in 27 histologically verified cases. Skeletal Radiol 1996; 25: 615–620 4 Astrom M, Westlin N. Blood flow in chronic Achilles tendinopathy. Clin Orthop Relat Res 1994; 308: 166–172 5 Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986; 1: 307–310 6 Bleakney RR, Tallon C, Wong JK, Lim KP, Maffulli N. Long-term ultrasonographic features of the Achilles tendon after rupture. Clin J Sport Med 2002; 12: 273–278 7 Culvenor AG, Cook JL, Warden SJ, Crossley KM. Infrapatellar fat pad size, but not patellar alignment, is associated with patellar tendinopathy. Scand J Med Sci Sports. doi:10.1111/j.1600-0838.2011.01334.x In press 8 Fornage BD. The hypoechoic normal tendon. A pitfall. J Ultrasound Med 1987; 6: 19–22 9 Fredberg U, Bolvig L. Significance of ultrasonographically detected asymptomatic tendinosis in the patellar and achilles tendons of elite soccer players: a longitudinal study. Am J Sports Med 2002; 30: 488–491 10 Fredberg U, Bolvig L, Andersen NT. Prophylactic training in asymptomatic soccer players with ultrasonographic abnormalities in Achilles and patellar tendons: the Danish Super League Study. Am J Sports Med 2008; 36: 451–460 11 Gaida JE, Cook JL, Bass SL, Austen S, Kiss ZS. Are unilateral and bilateral patellar tendinopathy distinguished by differences in anthropometry, body composition, or muscle strength in elite female basketball players? Br J Sports Med 2004; 38: 581–585 12 Harriss DJ, Atkinson G. Update – Ethical standards in sport and exercise science research. Int J Sports Med 2011; 32: 819–821 13 Jarvinen TA, Kannus P, Maffulli N, Khan KM. Achilles tendon disorders: etiology and epidemiology. Foot Ankle Clin 2005; 10: 255–266 14 Kader D, Saxena A, Movin T, Maffulli N. Achilles tendinopathy: some aspects of basic science and clinical management. Br J Sports Med 2002; 36: 239–249 15 Kannus P, Jozsa L. Histopathological changes preceding spontaneous rupture of a tendon. A controlled study of 891 patients. J Bone Joint Surg Am 1991; 73: 1507–1525 16 Kannus P, Niittymaki S, Jarvinen M, Lehto M. Sports injuries in elderly athletes: a three-year prospective, controlled study. Age Ageing 1989; 18: 263–270 17 Knobloch K, Yoon U, Vogt PM. Acute and overuse injuries correlated to hours of training in master running athletes. Foot Ankle Int 2008; 29: 671–676 18 Kujala UM, Sarna S, Kaprio J. Cumulative incidence of Achilles tendon rupture and tendinopathy in male former elite athletes. Clin J Sport Med 2005; 15: 133–135 ■ Proof copy for correction only. All forms of publication, duplication or distribution prohibited under copyright law. ■ Shaikh Z et al. Achilles Tendinopathy in Club Runners. Int J Sports Med 2012; 33: 1–5 IJSM/2377/16.1.2012/Macmillan IJSM/2377/16.1.2012/Macmillan 19 Kvist M. Achilles tendon injuries in athletes. Sports Med 1994; 18: 173–201 20 Leppilahti J, Orava S. Total Achilles tendon rupture. A review. Sports Med 1998; 25: 79–100 21 Longo UG, Rittweger J, Garau G, Radonic B, Gutwasser C, Gilliver SF, Kusy K, Zieliński J, Felsenberg D, Maffulli N. No influence of age, gender, weight, height, and impact profile in Achilles tendinopathy in masters track and field athletes. Am J Sports Med 2009; 37: 1400–1405 22 Maffulli N, Dymond NP, Capasso G. Ultrasonographic findings in subcutaneous rupture of Achilles tendon. J Sports Med Phys Fitness 1989; 29: 365–368 23 Maffulli N, Longo UG, Maffulli GD, Rabitti C, Khanna A, Denaro V. Marked pathological changes proximal and distal to the site of rupture in acute Achilles tendon ruptures. Knee Surg Sports Traumatol Arthrosc 2011; 19: 680–687 24 Maffulli N, Regine R, Angelillo M, Capasso G, Filice S. Ultrasound diagnosis of Achilles tendon pathology in runners. Br J Sports Med 1987; 21: 158–162 25 Maffulli N, Sharma P, Luscombe KL. Achilles tendinopathy: aetiology and management. J R Soc Med 2004; 97: 472–476 26 Malliaras P, Purdam C, Maffulli N, Cook J. Temporal sequence of greyscale ultrasound changes and their relationship with neovascularity and pain in the patellar tendon. Br J Sports Med 2010; 44: 944–947 27 Malliaras P, Richards PJ, Garau G, Maffulli N. Achilles tendon Doppler flow may be associated with mechanical loading among active athletes. Am J Sports Med 2008; 36: 2210–2215 28 Malliaras P, Voss C, Garau G, Richards P, Maffulli N. Achilles tendon shape and echogenicity on ultrasound among active badminton players. Scand J Med Sci Sports 29 Movin T, Kristoffersen-Wiberg M, Shalabi A, Gad A, Aspelin P, Rolf C. Intratendinous alterations as imaged by ultrasound and contrast medium-enhanced magnetic resonance in chronic achillodynia. Foot Ankle Int 1998; 19: 311–317 30 Nicol AM, McCurdie I, Etherington J. Use of ultrasound to identify chronic Achilles tendinosis in an active asymptomatic population. J R Army Med Corps 2006; 152: 212–216 Orthopedics & Biomechanics 31 O’Connor PJ, Grainger AJ, Morgan SR, Smith KL, Waterton JC, Nash AF. Ultrasound assessment of tendons in asymptomatic volunteers: a study of reproducibility. Eur Radio 2004; 14: 1968–1973 32 Ohberg L, Lorentzon R, Alfredson H. Neovascularisation in Achilles tendons with painful tendinosis but not in normal tendons: an ultrasonographic investigation. Knee Surg Sports Traumatol Arthrosc 2001; 9: 233–238 33 Ohberg L, Lorentzon R, Alfredson H. Eccentric training in patients with chronic Achilles tendinosis: normalised tendon structure and decreased thickness at follow up. Br J Sports Med 2004; 38: 8–11 34 Paavola M, Kannus P, Paakkala T, Pasanen M, Jarvinen M. Long-term prognosis of patients with achilles tendinopathy. An observational 8-year follow-up study. Am J Sports Med 2000; 28: 634–642 35 Paavola M, Paakkala T, Kannus P, Jarvinen M. Ultrasonography in the differential diagnosis of Achilles tendon injuries and related disorders. A comparison between pre-operative ultrasonography and surgical findings. Acta Radiol 1998; 39: 612–619 36 Richards PJ, McCall IW, Day C, Belcher J, Maffulli N. Longitudinal microvascularity in Achilles tendinopathy (power Doppler ultrasound, magnetic resonance imaging time-intensity curves and the Victorian Institute of Sport Assessment-Achilles questionnaire): a pilot study. Skeletal Radiol 2010; 39: 509–521 37 Silbernagel KG, Gustavsson A, Thomee R, Karlsson J. Evaluation of lower leg function in patients with Achilles tendinopathy. Knee Surg Sports Traumatol Arthrosc 2006; 14: 1207–1217 38 Tallon C, Maffulli N, Ewen SW. Ruptured Achilles tendons are significantly more degenerated than tendinopathic tendons. Med Sci Sports Exerc 2001; 33: 1983–1990 39 Vleck VE, Garbutt G. Injury and training characteristics of male elite, development squad, and club triathletes. Int J Sports Med 1998; 19: 38–42 40 Vora AM, Myerson MS, Oliva F, Maffulli N. Tendinopathy of the main body of the Achilles tendon. Foot Ankle Clin 2005; 10: 293–308 41 Ying M, Yeung E, Li B, Li W, Lui M, Tsoi CW. Sonographic evaluation of the size of Achilles tendon: the effect of exercise and dominance of the ankle. Ultrasound Med Biol 2003; 29: 637–642 ■ Proof copy for correction only. All forms of publication, duplication or distribution prohibited under copyright law. ■ Shaikh Z et al. Achilles Tendinopathy in Club Runners. Int J Sports Med 2012; 33: 1–5 View publication stats 5