Biomechanical analysis of two runners who developed leg injuries during a six-week transition to maximal running shoes: A case series.

Achilles tendinopathy (AT) and medial tibial stress syndrome (MTSS) are two of the most common running-related injuries. In a previous study investigating running biomechanics before and after a six-week transition to maximal running shoes, two runners dropped out of this study due to Achilles pain and shin pain, respectively. The purpose of this case series was to investigate running biomechanics in those two runners, identifying potential causes for injury in relation to maximal shoe use. Running biomechanics were collected in a laboratory setting for these two runners wearing both a maximal running shoe and traditional running shoe before the six-week transition using an 8-camera motion capture system and two embedded force plates. Both runners displayed prolonged eversion in the maximal shoe, which has been previously cited as a potential risk factor for developing Achilles tendinopathy and medial tibial stress syndrome. Relatively high loading rates and impact forces were also observed in the runner with shin pain in the maximal shoe, which may have contributed to their pain. More prospective research on injury rates in individuals running in maximal shoes is needed.

Is high soleus muscle activity during the stance phase of the running cycle a potential risk factor for the development of medial tibial stress syndrome? A prospective study.

To assess the impact of lower-leg muscle activity during the stance phase of running on the development of medial tibial stress syndrome (MTSS), in 123 healthy participants (18.2 ± 0.8 years), dynamic and static foot posture, and soleus and tibialis anterior muscle activity during the stance phase of running were measured before a 17-week track- and field-course. After the course, MTSS was identified in 20.5% of the participants. MTSS participants had a higher body mass (ES = 1.13), body mass index (BMI) (ES = 1.31), lower previous vigorous physical activity level (ES = 0.84) and VO2max (ES = 0.61), greater dynamic foot pronation (ES = 0.66), higher soleus peak EMG amplitude during the absorption (ES = 0.60) and propulsion phases (ES = 0.56) of running, and a history of MTSS (OR = 6.38) (p < 0.05). Stepwise logistic regression showed BMI, dynamic foot index, soleus peak EMG amplitude during propulsion, MTSS history and previous vigorous physical activity were predictors of MTSS. The model predicted 96.6% of the healthy participants and 56.5% of the MTSS participants and correctly classified 88.4% of overall cases. Coaches and sports-medicine professionals that screen for injury risk should consider adopting a comprehensive evaluation that includes these parameters.

Differences in muscle attachment proportion within the most common location of medial tibial stress syndrome in vivo.

INTRODUCTION: The medial tibial stress syndrome is one of the most common causes of running-related injuries. The primary study objective was to observe the attachment proportion of flexor digitorum longus and soleus, at the most common location of medial tibial stress syndrome, using ultrasonography, on a large cohort of young males and females to evaluate for gender-based anatomical differences. The secondary objective of this study was to investigate the relationship between the anatomical features and medial tibial stress syndrome. METHODS: In this study, we observed whether or not flexor digitorum longus and/or soleus attached at the middle and distal thirds of the medial margin of the tibia (most common location of medial tibial stress syndrome) using ultrasonography. History of medial tibial stress syndrome was defined by inquiries. RESULTS: The Chi2 tests showed that the attachment proportion of the soleus in female participants was significantly higher than that observed in male participants. In addition, Chi2 testing showed that there were no significant differences between attachment proportion of soleus of legs with history of medial tibial stress syndrome and legs without history of medial tibial stress syndrome, in both male and female participants. CONCLUSIONS: These results suggested that the anatomical features of flexor digitorum longus might be involved in medial tibial stress syndrome development, whereas the anatomical features of the soleus might not be involved in medial tibial stress syndrome development. LEVEL OF EVIDENCE: III, cross-sectional study.

Alignment of the rearfoot and foot pressure patterns of individuals with medial tibial stress syndrome: A cross-sectional study.

OBJECTIVE: To compare the rearfoot alignment (leg-heel angle, LHA) during standing and walking, and foot pressure during walking between individuals with medial tibial stress syndrome (MTSS) and asymptomatic individuals participating in daily sports. DESIGN: A cross-sectional study. SETTING: Research laboratory. PARTICIPANTS: MTSS (18 legs) and control (15 legs) participants. MAIN OUTCOME MEASURES: The LHA in the frontal plane during walking and standing; partial foot pressures expressed as the percentage of body weight (%PFP); and transverse width of the center of pressure (COP) path expressed as the percentage of foot width (%Trans) on walking. RESULTS: The LHA while walking was significantly higher in MTSS individuals, whereas the LHA while standing was not significantly different. The %PFPs of medial metatarsal areas were significantly higher in MTSS patients, whereas the %Trans was significantly lower. CONCLUSIONS: In individuals with MTSS, the LHA is similar to controls while standing but higher (more everted) while walking while there is higher pressure under the medial metatarsal areas and the COP is more medial. Rearfoot malalignment in individuals with mild to moderate MTSS can be detected on walking, even if the alignment on standing is normal.

Forefoot and hindfoot kinematics in subjects with medial tibial stress syndrome during walking and running.

Excessive foot pronation during static standing, walking and running has been reported as a contributing factor for the development of medial tibial stress syndrome (MTSS). The motion of foot pronation consists of hindfoot and forefoot motion. However, no previous studies have investigated forefoot and hindfoot kinematics during walking and running in subjects with MTSS. The current study sought to compare hindfoot and forefoot kinematics between subjects with and without MTSS while walking and running. Eleven subjects with MTSS and 11 healthy controls (each group containing 10 males and one female) participated in the current study. Segment angles of the hindfoot and forefoot during walking and running barefoot on a treadmill were recorded using three-dimensional kinematic analysis. An independent t-test was used to compare kinematic data between groups. Subjects with MTSS exhibited significantly greater hindfoot eversion and abduction (p < 0.05) during walking and running than subjects without MTSS, significantly greater forefoot eversion and abduction (p < 0.05) during walking, and significantly greater forefoot abduction during running (p < 0.05). Hindfoot and forefoot kinematics during walking and running were significantly different between subjects with and without MTSS. For prevention and rehabilitation of MTSS, it may be important to focus on not only hindfoot but also forefoot kinematics during both running and walking. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Microcrack-associated bone remodeling is rarely observed in biopsies from athletes with medial tibial stress syndrome.

The pathology of medial tibial stress syndrome (MTSS) is unknown. Studies suggest that MTSS is a bony overload injury, but histological evidence is sparse. The presence of microdamage, and its potential association with targeted remodeling, could provide evidence for the pathogenesis of MTSS. Understanding the pathology underlying MTSS could contribute to effective preventative and therapeutic interventions for MTSS. Our aim was to retrospectively evaluate biopsies, previously taken from the painful area in athletes with MTSS, for the presence of linear microcracks, diffuse microdamage and remodeling. Biopsies, previously taken from athletes with MTSS, were evaluated at the Department of Anatomy and Cell Biology at the Indiana University. After preparing the specimens by en bloc staining, one investigator evaluated the presence of linear microcracks, diffuse microdamage and remodeling in the specimens. A total of six biopsies were evaluated for the presence of microdamage and remodeling. Linear microcracks were found in 4 out of 6 biopsies. Cracking in one of these specimens was artefactual due to the biopsy procedure. No diffuse microdamage was seen in any of the specimens, and only one potential remodeling front in association with the microcracks. We found only linear microcracks in vivo in biopsies taken from the painful area in 50% of the athletes with MTSS, consistent with the relationship between linear cracks and fatigue-associated overloading of bone. The nearly universal absence of a repair reaction was notable. This suggests that unrepaired microdamage accumulation may underlie the pathophysiological basis for MTSS in athletes.

Factors Contributing to Medial Tibial Stress Syndrome in Runners: A Prospective Study.

PURPOSE: Medial tibial stress syndrome (MTSS) is one of the most common overuse injuries sustained by runners. Despite the prevalence of this injury, risk factors for developing MTSS remain unclear. The purpose of this study was to prospectively evaluate differences in passive range of motion, muscle strength, plantar pressure distributions, and running kinematics between runners who developed MTSS and those who did not. METHODS: Twenty-four National Collegiate Athletic Association Division 1 cross-country runners participated in this study. Participants underwent a clinical examination documenting passive range of motion and muscle strength at the hips and ankles. Plantar pressure analysis was used to quantify mediolateral pressure balances while walking and 3D motion capture was used to quantify running kinematics. Participants were followed up for a 2-yr period during which time any runners who developed MTSS were identified by the team's certified athletic trainer. RESULTS: Runners who developed MTSS demonstrated tighter iliotibial bands (P = 0.046; effect size [ES] = 1.07), weaker hip abductors (P = 0.008, ES = 1.51), more pressure under the medial aspect of their foot at initial foot contact (P = 0.001, ES = 1.97), foot flat (P < 0.001, ES = 3.25), and heel off (P = 0.034, ES = 1.30), greater contralateral pelvic drop (P = 0.021, ES = 1.06), and greater peak amounts (P = 0.017, ES = 1.42) and durations (P < 0.001, ES = 2.52) of rearfoot eversion during stance phase. A logistic regression (χ = 21.31, P < 0.001) indicated that every 1% increase in eversion duration increased odds of developing MTSS by 1.38 (P = 0.015). CONCLUSIONS: These findings demonstrate that the development of MTSS is multifactorial, with passive range of motion, muscle strength, plantar pressure distributions, and both proximal and distal kinematics all playing a role. We suggest that coaches or sports medicine professionals screening runners for injury risk consider adopting a comprehensive evaluation which includes all these areas.

Muscle stiffness of posterior lower leg in runners with a history of medial tibial stress syndrome.

Previous history of medial tibial stress syndrome (MTSS) is a risk factor for MTSS relapse, which suggests that there might be some physical factors that are related to MTSS development in runners with a history of MTSS. The relationship between MTSS and muscle stiffness can be assessed in a cross-sectional study that measures muscle stiffness in subjects with a history of MTSS, who do not have pain at the time of measurement, and in those without a history of MTSS. The purpose of this study was to compare the shear elastic modulus, which is an index of muscle stiffness, of all posterior lower leg muscles of subjects with a history of MTSS and those with no history and investigate which muscles could be related to MTSS. Twenty-four male collegiate runners (age, 20.0±1.7 years; height, 172.7±4.8 cm; weight, 57.3±3.7 kg) participated in this study; 14 had a history of MTSS, and 10 did not. The shear elastic moduli of the lateral gastrocnemius, medial gastrocnemius, soleus, peroneus longus, peroneus brevis, flexor hallucis longus, flexor digitorum longus, and tibialis posterior were measured using shear wave elastography. The shear elastic moduli of the flexor digitorum longus and tibialis posterior were significantly higher in subjects with a history of MTSS than in those with no history. However, there was no significant difference in the shear elastic moduli of other muscles. The results of this study suggest that flexor digitorum longus and tibialis posterior stiffness could be related to MTSS.

Influence of outdoor running fatigue and medial tibial stress syndrome on accelerometer-based loading and stability.

Medial tibial stress syndrome (MTSS) is a common overuse running injury with pathomechanics likely to be exaggerated by fatigue. Wearable accelerometry provides a novel alternative to assess biomechanical parameters continuously while running in more ecologically valid settings. The purpose of this study was to determine the influence of outdoor running fatigue and MTSS on both dynamic loading and dynamic stability derived from trunk and tibial accelerometery. Runners with (n=14) and without (n=16) history of MTSS performed an outdoor fatigue run of 3200m. Accelerometer-based measures averaged per lap included dynamic loading of the trunk and tibia (i.e. axial peak positive acceleration, signal power magnitude, and shock attenuation) as well as dynamic trunk stability (i.e. tri-axial root mean square ratio, step and stride regularity, and sample entropy). Regression coefficients from generalised estimating equations were used to evaluate group by fatigue interactions. No evidence could be found for dynamic loading being higher with fatigue in runners with MTSS history (all measures p>0.05). One significant group by running fatigue interaction effect was detected for dynamic stability. Specifically, in MTSS only, decreases mediolateral sample entropy i.e. loss of complexity was associated with running fatigue (p<0.01). The current results indicate that entire acceleration waveform signals reflecting mediolateral trunk control is related to MTSS history, a compensation that went undetected in the non-fatigued running state. We suggest that a practical outdoor running fatigue protocol that concurrently captures trunk accelerometry-based movement complexity warrants further prospective investigation as an in-situ screening tool for MTSS individuals.

The effect of a running task on muscle shear elastic modulus of posterior lower leg.

BACKGROUND: Medial tibial stress syndrome (MTSS) is one of the most common causes of exercise-related leg pain in runners. Because stopping training due to pain from MTSS could decrease the athlete's competitiveness, it is necessary to construct MTSS prevention and treatment programs. However, the effect of running, which is believed to cause MTSS, on shear elastic modulus of the posterior lower leg is unclear. Therefore, the purpose of this study was to investigate the effect of 30 min of running on shear elastic modulus of the posterior lower leg in healthy subjects. METHODS: Twenty healthy males volunteered to participate in this study (age, 20.9 ± 0.6 y; height, 169.6 ± 4.5 cm; weight, 62.6 ± 5.2 kg). The shear elastic modulus of the posterior lower leg was measured using ultrasonic shear wave elastography before and immediately after a 30-min running task. RESULTS: Shear elastic moduli of the flexor digitorum longus and tibialis posterior were significantly increased after 30 min running task. However, there were no significant changes in shear elastic moduli of the lateral gastrocnemius, medial gastrocnemius, peroneus longus and peroneus brevis. CONCLUSION: The results suggested that the increases in shear elastic moduli of flexor digitorum longus and tibialis posterior after running could be a risk factor for running-related MTSS development.

Shockwave treatment for medial tibial stress syndrome in military cadets: A single-blind randomized controlled trial.

Medial tibial stress syndrome (MTSS) is a common injury in athletes and soldiers. Several studies have demonstrated the effectiveness of extracorporeal shockwave treatment (ESWT) in athletes with MTSS. OBJECTIVE: To assess whether one session of focused ESWT is effective in the treatment of military cadets with MTSS. DESIGN: A randomized, prospective, controlled, single-blind, parallel-group clinical study. LEVEL OF EVIDENCE: Ib. SETTING: Military School of Cadets of the Colombian Army. METHODS: Forty-two military cadets with unilateral chronic MTSS were randomly assigned to either one session of focused electromagnetic ESWT (1500 pulses at 0.20 mJ/mm2) plus a specific exercise programme (muscle stretching and strengthening exercises) or the exercise programme alone. The primary endpoint was change in asymptomatic running test (RT) duration at four weeks from baseline. Secondary endpoints were changes in the visual analogue scale (VAS) after running and modified Roles and Maudsley (RM) score also at four weeks from baseline. RESULTS: ESWT patients were able to run longer. Mean RT after four weeks was 17 min 33 s (SE: 2.36) compared to 4 min 48 s (SE: 1.03) in the exercise-only group (p = 0.000). Mean VAS after running was 2.17 (SE: 0.44) in the ESWT group versus 4.26 (SE: 0.36) in the exercise-only group (p = 0.001). The ESWT group had a significantly higher RM score, with excellent or good results for 82.6% of patients vs. 36.8% in the exercise-only group (p = 0.002). No significant adverse effects of ESWT were observed. CONCLUSION: A single application of focused shockwave treatment in combination with a specific exercise programme accelerates clinical and functional recovery in military cadets with MTSS.

Biomechanical Factors Associated With Achilles Tendinopathy and Medial Tibial Stress Syndrome in Runners.

BACKGROUND: There is disagreement in the literature regarding whether the excessive excursion or velocity of rearfoot eversion is related to the development of 2 common running injuries: Achilles tendinopathy (AT) and medial tibial stress syndrome (MTSS). An alternative hypothesis suggests that the duration of rearfoot eversion may be an important factor. However, the duration of eversion has received relatively little attention in the biomechanics literature. HYPOTHESIS: Runners with AT or MTSS will demonstrate a longer duration of eversion but not greater excursion or velocity of eversion compared with healthy controls. STUDY DESIGN: Controlled laboratory study. METHODS: Forty-two runners participated in this study (13 with AT, 8 with MTSS, and 21 matched controls). Participants were evaluated for lower extremity alignment and flexibility, after which a 3-dimensional kinematic and kinetic running gait analysis was performed. Differences between the 2 injuries and between injured and control participants were evaluated for flexibility and alignment, rearfoot kinematics, and 3 ground-reaction force metrics. Binary logistic regression was used to evaluate which variables best predicted membership in the injured group. RESULTS: Injured participants, compared with controls, demonstrated higher standing tibia varus angles (8.67° ± 1.79° vs 6.76° ± 1.75°, respectively; P = .002), reduced static dorsiflexion range of motion (6.14° ± 5.04° vs 11.19° ± 5.10°, respectively; P = .002), more rearfoot eversion at heel-off (-6.47° ± 5.58° vs 1.07° ± 2.26°, respectively; P < .001), and a longer duration of eversion (86.02% ± 15.65% stance vs 59.12% ± 16.50% stance, respectively; P < .001). There were no differences in the excursion or velocity of eversion. The logistic regression (χ2 = 20.84, P < .001) revealed that every 1% increase in the duration of eversion during the stance phase increased the odds of being in the injured group by 1.08 (95% CI, 1.023-1.141; P = .006). CONCLUSION: Compared with healthy controls, runners currently symptomatic with AT or MTSS have a longer duration of eversion but not greater excursion or velocity of eversion. CLINICAL RELEVANCE: Static measures of the tibia varus angle and dorsiflexion range of motion, along with dynamic measures of the duration of eversion, may be useful for identifying runners at risk of sustaining AT or MTSS.

Ankle and toe muscle strength characteristics in runners with a history of medial tibial stress syndrome.

BACKGROUND: A high proportion of flexor digitorum longus attachment is found at the posteromedial border of the tibia, which is the most common location of medial tibial stress syndrome (MTSS). Therefore, plantar flexion strength of the lesser toes could be related to MTSS; however, the relationship between MTSS and muscle strength of the hallux and lesser toes is not yet evaluated due to the lack of quantitative methods. This study investigated the muscle strength characteristics in runners with a history of MTSS by using a newly developed device to measure the muscle strength of the hallux, lesser toes, and ankle. METHODS: This study comprised 27 collegiate male runner participants (20.0 ± 1.6 years, 172.1 ± 5.1 cm, 57.5 ± 4.0 kg). Maximal voluntary isometric contraction (MVIC) torque of the plantar flexion, dorsiflexion, inversion, and eversion of the ankle were measured by using an electric dynamometer. MVIC torque of the 1st metatarsophalangeal joint (MTPJ) and 2nd-5th MTPJ were measured by using a custom-made torque-measuring device. MVIC torques were compared between runners with and without a history of MTSS. RESULTS: MVIC torque of the 1st MTPJ plantar flexion was significantly higher in runners with a history of MTSS than in those without it. In contrast, there were no significant differences in the MVIC torque values of the 2nd-5th MTPJ plantar flexion and each MVIC torque of the ankle between runners with and without a history of MTSS. CONCLUSION: A history of MTSS increased the isometric FHL strength.

Medial Tibial Stress Syndrome in Active Individuals: A Systematic Review and Meta-analysis of Risk Factors.

CONTEXT: Medial tibial stress syndrome (MTSS) is a common condition in active individuals and presents as diffuse pain along the posteromedial border of the tibia. OBJECTIVE: To use cross-sectional, case-control, and cohort studies to identify significant MTSS risk factors. DATA SOURCES: Bibliographic databases (PubMed, Scopus, CINAHL, SPORTDiscus, EMBASE, EBM Reviews, PEDRo), grey literature, electronic search of full text of journals, manual review of reference lists, and automatically executed PubMed MTSS searches were utilized. All searches were conducted between 2011 and 2015. STUDY SELECTION: Inclusion criteria were determined a priori and included original research with participants' pain diffuse, located in the posterior medial tibial region, and activity related. STUDY DESIGN: Systematic review with meta-analysis. LEVEL OF EVIDENCE: Level 4. DATA EXTRACTION: Titles and abstracts were reviewed to eliminate citations that did not meet the criteria for inclusion. Study characteristics identified a priori were extracted for data analysis. Statistical heterogeneity was examined using the I2 index and Cochran Q test, and a random-effects model was used to calculate the meta-analysis when 2 or more studies examined a risk factor. Two authors independently assessed study quality. RESULTS: Eighty-three articles met the inclusion criteria, and 22 articles included risk factor data. Of the 27 risk factors that were in 2 or more studies, 5 risk factors showed a significant pooled effect and low statistical heterogeneity, including female sex (odds ratio [OR], 2.35; CI, 1.58-3.50), increased weight (standardized mean difference [SMD], 0.24; CI, 0.03-0.45), higher navicular drop (SMD, 0.44; CI, 0.21-0.67), previous running injury (OR, 2.18; CI, 1.00-4.72), and greater hip external rotation with the hip in flexion (SMD, 0.44; CI, 0.23-0.65). The remaining risk factors had a nonsignificant pooled effect or significant pooled effect with high statistical heterogeneity. CONCLUSION: Female sex, increased weight, higher navicular drop, previous running injury, and greater hip external rotation with the hip in flexion are risk factors for the development of MTSS.

Shear Modulus of the Lower Leg Muscles in Patients with Medial Tibial Stress Syndrome.

This study aimed to investigate the in vivo kinematics of shear modulus of the lower leg muscles in patients with medial tibial stress syndrome (MTSS). The study population included 46 limbs with MTSS and 40 healthy limbs. The shear modulus of the medial head of the gastrocnemius, lateral head of the gastrocnemius, soleus, peroneus longus and tibialis anterior muscles were measured using shear wave ultrasound elastography. As a result, the shear modulus of the lower leg muscles was significantly greater in patients with MTSS than in healthy patients (p < 0.01). Based on the differences in shear modulus of lower leg muscles between the patients with MTSS and healthy patients, the measurements obtained via shear wave ultrasound elastography could be used to evaluate risk factors of MTSS.

Forefoot flexibility and medial tibial stress syndrome.

PURPOSE: To investigate the association between medial tibial stress syndrome (MTSS) and morphology and flexibility of the foot arches. METHODS: 131 feet from 74 healthy subjects and 31 feet from 27 patients with MTSS were classified as normal feet (n=78 in 40 subjects), flat feet (n=53 in 34 subjects), or MTSS feet (n=31 in 27 patients). The medial longitudinal arch (MLA) ratio and the transverse arch length (TAL) were measured in both rearfoot and forefoot loading positions. The difference between the 2 positions indicated the flexibility of the MLA (diff-MLA ratio) and the transverse arch (diff- TAL). RESULTS: The MLA ratio was higher in normal feet than MTSS feet or flat feet (15.1% vs. 12.8% vs. 12.3%, p<0.001). The diff-TAL was lower in MTSS feet than normal feet or flat feet (0.4% vs. 0.8% vs. 0.9%, p<0.001]). The 3 groups were comparable in terms of the diff-MLA ratio and the TAL. Respectively for the MLA ratio and the diff-TAL, the cut-off value was 11.9% and 0.61% based on the Youden index. The sensitivity, specificity, and odds ratio of the cut-off value were 0.4, 0.9, and 4.8 for the MLA ratio, and 0.6, 0.7, and 9.8 for the diff-TAL, respectively. CONCLUSION: Decreased flexibility of the transverse arch and decreased MLA ratio are risk factors for MTSS. In contrast, the flexibility of the MLA and the height of the transverse arch were not risk factors for MTSS.

Treatment of medial tibial stress syndrome according to the fascial distortion model: a prospective case control study.

Medial tibial stress syndrome (MTSS) is a common problem among athletes and soldiers. There is no proven theory that could explain the pathophysiology of shin splints. The therapies described so far are time-consuming and involve a high risk of relapse. The method according to the fascial distortion model (FDM) addresses local changes in the area of the lower leg fascia. It is suited to reduce pain and functional impairments associated with this symptom complex by applying targeted manual techniques. 32 patients (male: 30; female: 2) participated in this study. Visual analogue scale (VAS) was used for the quantification of pain. Scores were also given to rate the maximum painless exercise tolerance of the patients. Subsequently treatment of the crural fascia was performed. Patients retested ability of running and jumping. Therapy was continued until full exercise tolerance or painlessness was reached. A significant reduction of the VAS pain score from 5.2 to 1.1 could be achieved (P < 0.001). The impairment of exercise tolerance could be reduced from 7 to 2 points (P < 0.001). The duration of treatment was 6.3 (SD: 4.3) days on average. The FDM therapy is a potential effective method for acute treatment of MTSS.

Medial tibial pain pressure threshold algometry in runners.

PURPOSE: Pressure algometry (PA) may provide an objective and standardised tool in assessing palpation pain over the tibia. The purpose of this study was to analyse the intra-rater repeatability of PA and to determine whether tibial tenderness in healthy runners differ from runners with medial tibial stress syndrome (MTSS). METHODS: Pressure algometry was performed on 20 asymptomatic runners (40 legs) and 9 MTSS patients (14 symptomatic legs) at standardised locations along the medial border of the tibia. Intra-rater reliability was assessed in 10 randomly selected asymptomatic runners through repeated measurements 2 weeks later. RESULTS: Intra-rater reliability was moderate to excellent (ICC 0.53-0.90) in asymptomatic runners. Pain pressure threshold (PPT) was significantly reduced at 2/9-5/9 of the distance from the medial malleolus to the medial tibial condyle (p = 0.002-0.022). There was evidence of a statistically significant association between both height and weight, and PPT from the 3/9 (r = 0.416, p = 0.008) to 7/9 (r = 0.334, p = 0.035) and 3/9 (r = 0.448, p = 0.004) to 6/9 (r = 0.337, p = 0.034) area, respectively. In both MTSS patients and healthy runners, there was evidence of lower PPT in females compared to males (p = 0.0001-0.049) and a negative association between age and PPT (p = 0.001-0.033). MTSS patients had significantly lower PPT at the 3/9 site (p = 0.048) compared to asymptomatic runners. CONCLUSION: Pain pressure threshold algometry can be incorporated into MTSS clinical assessment to objectively assess pain and monitor progress. The presence of reduced medial tibial PPT in asymptomatic runners suggests that clinicians may not need to await resolution of medial tibia tenderness before allowing return to sport in MTSS patients.

Risk factors and prognostic indicators for medial tibial stress syndrome.

The objective of the study was to examine the risk factors and prognostic indicators for medial tibial stress syndrome (MTSS). In total, 35 subjects were included in the study. For the risk factor analysis, the following parameters were investigated: hip internal and external ranges of motion, knee flexion and extension, dorsal and plantar ankle flexion, hallux flexion and extension, subtalar eversion and inversion, maximal calf girth, lean calf girth, standing foot angle and navicular drop test. After multivariate regression decreased hip internal range of motion, increased ankle plantar flexion and positive navicular drop were associated with MTSS. A higher body mass index was associated with a longer duration to full recovery. For other prognostic indicators, no relationship was found.

Inverse relationship between the complexity of midfoot kinematics and muscle activation in patients with medial tibial stress syndrome.

Medial tibial stress syndrome is a common overuse injury characterized by pain located on the medial side of the lower leg during weight bearing activities such as gait. The purpose of this study was to apply linear and nonlinear methods to compare the structure of variability of midfoot kinematics and surface electromyographic (SEMG) signals between patients with medial tibial stress syndrome and healthy controls during gait. Fourteen patients diagnosed with medial tibial stress syndrome and 11 healthy controls were included from an orthopaedic clinic. SEMG from tibialis anterior and the soleus muscles as well as midfoot kinematics were recorded during 20 consecutive gait cycles. Permuted sample entropy and permutation entropy were used as a measure of complexity from SEMG signals and kinematics. SEMG signals in patients with medial tibial stress syndrome were characterized by higher structural complexity compared with healthy controls (p<0.001) while it was the opposite for the midfoot kinematics (p=0.01). Assessing the complexity of midfoot kinematics and SEMG activation pattern enabled a precise characterization of gait in patients with medial tibial stress syndrome. The reported inverse relationship in foot kinematics and SEMG complexity most likely point towards separated control processes governing gait variability.