Do habitual foot-strike patterns in running influence functional Achilles tendon properties during gait?

The capacity of foot-strike running patterns to influence the functional properties of the Achilles tendon is controversial. This study used transmission-mode ultrasound to investigate the influence of habitual running foot-strike pattern on Achilles tendon properties during barefoot walking and running. Fifteen runners with rearfoot (RFS) and 10 with a forefoot (FFS) foot-strike running pattern had ultrasound transmission velocity measured in the right Achilles tendon during barefoot walking (≈1.1 ms-1) and running (≈2.0 ms-1). Temporospatial gait parameters, ankle kinematics and vertical ground reaction force were simultaneously recorded. Statistical comparisons between foot-strike patterns were made using repeated measure ANOVAs. FFS was characterised by a significantly shorter stance duration (-4%), greater ankle dorsiflexion (+2°), and higher peak vertical ground reaction force (+20% bodyweight) than RFS running (P < .05). Both groups adopted a RFS pattern during walking, with only the relative timing of peak dorsiflexion (3%), ground reaction force (1-2%) and peak vertical force loading rates (22-23%) differing between groups (P < .05). Peak ultrasound transmission velocity in the Achilles tendon was significantly higher in FFS during walking (≈100 ms-1) and running (≈130 ms-1) than RFS (P < .05). Functional Achilles tendon properties differ with habitual footfall patterns in recreational runners.

Achilles tendon loading patterns during barefoot walking and slow running on a treadmill: An ultrasonic propagation study.

Measurement of tendon loading patterns during gait is important for understanding the pathogenesis of tendon "overuse" injury. Given that the speed of propagation of ultrasound in tendon is proportional to the applied load, this study used a noninvasive ultrasonic transmission technique to measure axial ultrasonic velocity in the right Achilles tendon of 27 healthy adults (11 females and 16 males; age, 26 ± 9 years; height, 1.73 ± 0.07 m; weight, 70.6 ± 21.2 kg), walking at self-selected speed (1.1 ± 0.1 m/s), and running at fixed slow speed (2 m/s) on a treadmill. Synchronous measures of ankle kinematics, spatiotemporal gait parameters, and vertical ground reaction forces were simultaneously measured. Slow running was associated with significantly higher cadence, shorter step length, but greater range of ankle movement, higher magnitude and rate of vertical ground reaction force, and higher ultrasonic velocity in the tendon than walking (P < 0.05). Ultrasonic velocity in the Achilles tendon was highly reproducible during walking and slow running (mean within-subject coefficient of variation < 2%). Ultrasonic maxima (P1, P2) and minima (M1, M2) were significantly higher and occurred earlier in the gait cycle (P1, M1, and M2) during running than walking (P < 0.05). Slow running was associated with higher and earlier peaks in loading of the Achilles tendon than walking.

Deficits 10-years after Achilles tendon repair.

The purpose of this study was to determine the long-term impact of surgical repair and subsequent 6-week immobilization of an Achilles tendon rupture on muscle strength, muscle strength endurance and muscle activity. 63 patients participated in this study on average 10.8 ± 3.4 years after surgically repaired Achilles tendon rupture and short-term immobilization. Clinical function was assessed and muscle strength, strength endurance and muscle activity were measured using a dynamometer and electromyography. Ankle ROM, heel height during heel-raise tests and calf circumference were smaller on the injured than on the contralateral side. Ankle torques during the concentric dorsiflexion tasks at 60 °/sec and 180 °/sec and ankle torques during the eccentric plantarflexion task and during the concentric plantarflexion task at 60 °/sec for the injured leg were significantly lower than those for the contralateral leg. The total work during a plantarflexion exercise at 180 °/sec was 14.9% lower in the injured compared to the contralateral leg (p < 0.001). Muscle activity for the gastrocnemius muscle during dorsiflexion tasks was significantly higher in the injured than in the contralateral limb. Limited ankle joint ROM and increased muscle activity in the injured leg suggest compensatory mechanisms to account for differences in muscle morphology and physiology caused by the injury.

The influence of Nordic Walking training on sit-to-stand transfer in Parkinson patients.

Neurodegenerative processes in Parkinson's disease (PD) particularly affect activities of daily living (ADL). Problems of patients with PD in sit-to-stand (STS) performance have been verified before, but not the effects of training on biomechanical measures of STS function. This pilot study aimed to analyse effects of 12 weeks of Nordic Walking training and severity of PD: healthy controls (CO), least (UPDRS A) and more severe (UPDRS B) affected PA on selected functional outcome measures. We expected improvements in PD similar to CO, with better performance of the unstable second phase and faster execution of the entire movement with higher velocities of centre of gravity (COG). 3D kinematics of 22 PD and 18 CO subjects before and after training, were recorded using a motion analysis system (Vicon, Oxford). We compared five outcome measures for STS in 11 PD and 11 CO, matched according to age, gender, height, and weight. Effects of Nordic Walking training were not statistically significant but indicated different patterns which depended on the values of patient's UPDRS score (part III, motor functions). Time required for STS performance increased and horizontal and vertical velocity of COG decreased in UPDRS B, which could be due to progression of PD during the training period. In contrast, UPDRS A showed similar effects as CO. The effects of Nordic Walking as an easy, economic and low-risk intervention on STS in PD depend on the degree of PD. Our findings may help scientists, patients, and therapists to adjust sport-physiological interventions.

Sex-related differences in foot shape of adult Caucasians--a follow-up study focusing on long and short feet.

The study's purpose was to substantiate findings on sex-related differences in foot morphology focusing on fringe sizes. Altogether, 287 Caucasian adults with long or short feet were scanned. Data were analysed together with data from 847 subjects from a previous study with comparable inclusion criteria and anthropometric data by: (1)comparing absolute measures within 237-277 mm foot length (FL); (2) comparing averaged measures across sizes in % of foot length for 203-323 mm FL; (3) reclassifying the additional subjects into a previously defined foot type classification. Male feet were wider and higher for the same FL. Averaged across sizes, no relevant differences between sexes were found for widths and heights. Slender or flat-pointed foot types were more common in longer feet, shorter feet tended to be bigger. Definitions for 'long' and 'short' are sex-related with an offset of three shoe sizes (EU). Results of this follow-up study on long and short feet can substantiate previous findings mainly described for the most common sizes. STATEMENT OF RELEVANCE: Improper footwear can cause pain and injury and proper fit is a major criterion for shoe buyers. Knowledge about sex-related differences in foot shape is important for shoe design. This study supplements the field of knowledge for very small and large feet.

Kinematic classification of iliotibial band syndrome in runners.

Several inconsistent causative biomechanical factors are considered to be crucial in the occurrence of iliotibial band syndrome (ITBS). The focus of this study was on assessing differences in the kinematic characteristics between healthy runners [control group (CO)] and runners with ITBS in order to recommend treatment strategies to deal with this injury. Three-dimensional kinematics of barefoot running was used in the biomechanical setup. Both groups were matched with respect to gender, height and weight. After determining drop outs, the final population comprised 36 subjects (26 male and 10 female): 18 CO and 18 ITBS (13 male and five female, each). Kinematic evaluations indicate less hip adduction and frontal range of motion at the hip joint in runners with ITBS. Furthermore, maximum hip flexion velocity and maximum knee flexion velocity were lower in runners with ITBS. Lack of joint coordination, expressed as earlier hip flexion and a tendency toward earlier knee flexion, was found to be another discriminating variable in subjects with ITBS compared with CO subjects. We assume that an increase in range of motion at the hip joint, stretching of the hip abductors, as well as stretching the hamstrings, calf muscles and hip flexors will help treat ITBS.

[Relation between pelvis malposition and functional knee pain by long distance running]. / Zusammenhang zwischen einseitiger Beckenfehlstellung und funktionell bedingten Knieschmerzen am Beispiel des Langstreckenlaufs.

PURPOSE: During endurance run knee problems often appear. This study wants to show the connection between a one- sided malposition of the pelvis and knee joint pain during endurance running. METHOD: We tested endurance runners which had pelvis malposition and knee pain. Therefore 100 athletes were tested, 50 with knee pain and 50 without knee pain. Manual examination and clinical instruments were used for examination of sacroiliac joints for measurement of vertical distances between spinae iliacae anteriores superiores. Collected data were analyzed by appropriate statistical methods. RESULTS: The results show that there is a connection between a one- sided pelvic malposition and knee pain during endurance running. These relations are probably realized by changes in lower extremity dysfunction as a result of pathological chains. The one sided pelvis malposition was in the control group significant higher (0.9 ± 0.4 cm) than in the control group (0.3 ± 0.2 cm). CONCLUSION: There is a correlation between knee pain and os coxae malposition. (It is necessary in examine and treat the the cause- and effect chain to prevent injuries).

[Reliability of a measurement technique to characterise standing properties and to quantify balance capabilities of healthy subjects on an unstable oscillatory platform (Posturomed)]. / Zuverlässigkeitsprüfung eines Messverfahrens zur Charakterisierung des Standverhaltens und Quantifizierung des Balancevermögens auf einer instabilen Plattform (Posturomed).

INTRODUCTION: Specific sensomotoric training is recommended to improve walking dysfunctions, prevent injurious falls or improve the reaction capacities of athletes. The oscillatory Posturomed platform can be used as a simple measuring procedure to characterise balance ability. Standard values for the one legged stance or test-retest reliability are unknown. METHOD: 55 healthy subjects (37 +/- 15 years) were tested during one legged stance on the unstable Posturomed platform. We recorded the total path of the platform in mm as balance recovery movements (BRM) as well as the ratio of failed attempts. To evaluate Test-Retest-Reliability, 12 subjects were retested one month later. RESULTS: To maintain balance, healthy subjects required twice as many BRM in anterior-posterior (AP) direction (40.7 +/- 26 mm) as in medio-lateral (ML) (17.4 +/- 8 mm). 8 % of the recorded attempts were counted as failed attempts due to subjects' unstable standing. On average, subjects required 15.5 +/- 18 mm less BMR when standing on their stronger leg than on the other leg. Younger subjects (25 +/- 2 y) required less BMR than older (59 +/- 11 y) subjects (49.2 versus 64.7 mm, p = 0.006). Subjects with a high level of physical training required less BMR. Test-Retest measurements showed an average difference of 3.9 +/- 6.1 mm. DISCUSSION: The Posturomed Platform can be used to evaluate stance ability and characterise the patterns of one legged stance. The measurements are reproducible, but include a small learning effect. Further studies including EMG could provide more understanding of neuromuscular control mechanisms and their adaption to training.

A new approach to children's footwear based on foot type classification.

Current shoe designs do not allow for the comprehensive 3-D foot shape, which means they are unable to reproduce the wide variability in foot morphology. Therefore, the purpose of this study was to capture these variations of children's feet by classifying them into groups (types) and thereby provide a basis for their implementation in the design of children's shoes. The feet of 2867 German children were measured using a 3-D foot scanner. Cluster analysis was then applied to classify the feet into three different foot types. The characteristics of these foot types differ regarding their volume and forefoot shape both within and between shoe sizes. This new approach is in clear contrast to previous systems, since it captures the variability of foot morphology in a more comprehensive way by using a foot typing system and therefore paves the way for the unimpaired development of children's feet. Previous shoe systems do not allow for the wide variations in foot morphology. A new approach was developed regarding different morphological foot types based on 3-D measurements relevant in shoe construction. This can be directly applied to create specific designs for children's shoes.

Sex-related differences in foot shape.

The purpose of the study was to investigate sex-related differences in foot morphology. In total, 847 subjects were scanned using a 3-D-footscanner. Three different analysis methods were used: (1) comparisons were made for absolute foot measures within 250-270 mm foot length (FL); (2) and for averaged measures (% FL) across all sizes; (3) the feet were then classified using a cluster analysis. Within 250-270 mm FL, male feet were wider and higher (mean differences (MD) 1.3-5.9 mm). No relevant sex-related differences could be found in the comparison of averaged measures (MD 0.3-0.6% FL). Foot types were categorised into voluminous, flat-pointed and slender. Shorter feet were more often voluminous, longer feet were more likely to be narrow and flat. However, the definition of 'short' and 'long' was sex-related; thus, allometry of foot measures was different. For shoe design, measures should be derived for each size and sex separately. Different foot types should be considered to account for the variety in foot shape. Improper footwear can cause foot pain and deformity. Therefore, knowledge of sex-related differences in foot measures is important to assist proper shoe fit in both men and women. The present study supplements the field of knowledge within this context with recommendations for the manufacturing of shoes.