Lower extremity pathologies caused by abnormal biomechanics of the subtalar joint are commonly seen in the health care setting. Certain foot types will predispose an individual to excessive amounts of subtalar joint pronation or supination during gait. Subtalar joint movement is transmitted proximally to the lower extremity during gait and excessive amounts of pronation or supination can lead to altered biomechanics in the lower extremity with development of various lower extremity injuries. The purpose of this study is to analyze the biomechanical events of the subtalar joint of the foot during gait in order to show how abnormalities in these events can be responsible for lower extremity injuries. This information will enable clinicians to conduct a more accurate and comprehensive assessment of the cause of lower extremity injuries. By assessing the cause of lower extremity injury, a rapid recovery can be anticipated and recurrence of the injury can be prevented

Subtalar joint movement is transmitted proximally to the lower extremity and distally to the forefoot during gait. Thus, the entire lower kinetic chain is influenced by abnormal subtalar joint biomechanics. If the subtalar joint is forced to compensate for structural deformities of the foot and leg, various lower extremity injuries are likely to develop. The purpose of this study is to examine the normal and abnormal biomechanics of the subtalar joint. In the process, the clinician will be able to identify various subtalar joint abnormalities and relate these to their respective lower kinetic chain pathologies. By correctly assessing the cause of the lower extremity injury, the examiner will be able to initiate the appropriate form of treatment

The current study aimed using a two-experiment musculoskeletal simulation-based approach, measuring ACL biomechanics, knee joint kinematics and lower extremity joint loading to examine the effects of both a prophylactic knee sleeve on 1. a sport specific change of direction movement in female footballers and 2. a single leg landing in male footballers. Experiment 1 examined 12 female university first team level footballers (age 20.2 ± 1.34 years, height 1.61 ± 0.06 m, body mass 57.2 ± 5.6 kg) undertaking a 45° cutting movement in sleeve and no-sleeve conditions. Experiment 2 examined 10 male university first team level footballers (age 21.1 ± 1.13 years, height 1.77 ± 0.1 m, body mass 71.9 ± 8.6 kg) undertaking a single leg drop jump landing in sleeve and no-sleeve conditions. In each experiment, data was collected in a biomechanics laboratory and three-dimensional motion capture and ground reaction force information was collected. Three-dimensional kinematics, three-dimensional knee kinetics and ACL ligament forces/ strains were measured using musculoskeletal simulation, and participants were also asked to subjectively rate the knee sleeve in terms of both comfort and stability. Experiment 1 showed that the sleeve condition was associated with greater ACL strain (sleeve = 13.57% and no-sleeve = 10.26%) and forces (sleeve = 1.19BW and no-sleeve = 0.94BW). In addition, the brace condition also enhanced lateral compressive tibiofemoral (sleeve = 4.70BW and no-sleeve = 4.20BW) and total compressive tibiofemoral force (sleeve = 11.73BW and no-sleeve = 11.08BW). Finally, for the subjective ratings, participants indicated that the knee sleeve significantly improved perceived comfort and stability. Experiment 2 did not reveal and statistical differences between knee sleeve and no-sleeve conditions, nor any effects of the knee sleeve on subjective ratings of comfort or stability. Therefore, the findings from the current investigation suggest that the prophylactic knee sleeve examined in the current investigation does not appear to reduce the biomechanical parameters linked to the aetiology of knee pathologies in male/ female footballers

Summary: Walking for healthy humans is a basic everyday activity. In patients, especially those with neurologic disorders, the walking pattern can strongly deviate from those of healthy humans. For clinicians it is crucial to distinguish between primary and secondary gait deviations to plan the appropriate treatment. Primary gait deviations are causative and the target of therapy. Secondary gait deviations can be either active compensation or passive physical effects. Both do not require treatment as they are resolved when the primary impairment is corrected. The focus of this thesis relied on the walking patterns of patients with different primary pa-thologies, e.g. patients with spasticity or orthopaedic patients. The aim was to identify princi-pals of a pathological gait, with intention that it can further assist in differentiating between primary and secondary gait deviations. Three-dimensional gait analysis, driven by a marker-based movement analysis system (VICON) provided the data. All studies had a retrospective study design. Besides joint kinematics and surface electromyographic (EMG) data, muscle strength data were also analysed. It was investigated which parameters, such as muscle strength or orthotics, influences the gait of patients besides the primary pathology. First, a method to detect a characteristic gait cycle for one subject was developed and evalu-ated. Based on Principal Component Analysis, the algorithm selects a trial that is closest to the median of all trials across different parameters, e.g. joint angle curves. The Selection Method for a Representative Trial (SMaRT) evaluates the data automatically, without subjec-tive bias, and provides full repeatability. Furthermore, SMaRT required 1.4 s to analyse 100 datasets. Hereby, it was more than three orders of magnitude faster than the visual selection done by experts. Most importantly, the error rate of SMaRT with 1.2% was small; hence, the algorithm is relatively robust against a limited number of contaminated data. The algorithm can be individually adapted to any number and type of input parameters, e.g. joint moments, joint powers, etc. SMaRT is generally applicable to any type of curves derived by movement analysis, e.g. in the field of sports science. The representative trial for each subject was the base for further analysis. To analyse the influence of muscle strength on gait deviations, patients were clustered into seven groups according to their pathology: orthopaedic patients uni-/bilateral, neurologic pa-tients with uni-/bilateral flaccid/spastic muscles, with/ without thoracal control. The effect of muscle strength on the lower joint kinematics was calculated by generalised least squares. Muscle strength had a negative effect on gait kinematics, measured in the form of a Gait Pro-file Score (GPS). The weaker the patients were, the stronger the GPS differed from the norm. This effect was not significantly different across the different patient groups. Nevertheless, differences between the patients were found in the GPS offsets at normal muscle strength. The more severe the pathology of the patients, the higher the observed GPS offset was. Patients with orthopaedic diseases and patients with hemiplegic cerebral palsy were able to produce normal GPS values (orthopaedic unilateral: 4.9°±0.7, orthopaedic bilateral: 5.0°±1.0, hemi-plegia: 5.4°±1.1). Patients with diplegia, tetraplegia, or flaccid muscles bilaterally differed significantly. Surprisingly, patients with diplegia and patients with flaccid muscles bilaterally showed the same GPS offsets to the reference group of 1.7° ±0.5. Even when comparing the particular joints, very few differences between these two groups were found. Furthermore, muscle strength was observed to be associated with abnormal EMG timing, more exactly with premature plantarflexor activity during loading response of walking. Across all patient groups, a normal muscle strength reduced the number of patients with pre-mature EMG by more than 10%. The only exception was the neurologic patient group with unilateral flaccid muscles. However the small amount of patients within this group might have biased the results. Abnormal EMG timing was prevalent across all pathology groups, indicat-ing that it is not only caused by the primary pathology, e.g. spasticity. Lastly, it was investigated whether a change in the gait kinematics of the lower body results in adaptations in the upper body. Hemiplegic cerebral palsy patients were compared when walk-ing on their toes (barefoot condition) to a heel-toe gait condition evoked by wearing a hinged ankle-foot orthosis. No clinically relevant changes were observed in the trunk angle parame-ters when walking with orthoses compared to the barefoot condition. Nevertheless, the unaf-fected arm increased its swing amplitude and compensates for the reduced arm swing on the hemiplegic side. In conclusion, kinematic changes of the sagittal ankle pattern in the specific hemiplegic pa-tients do not result in a normalisation of the upper body kinematics. Consequently, none of the upper body abnormalities in this group seemed to be a secondary gait deviation resulting from toe walking. Contrarily, joint kinematics (GPS) of the lower body and activity timing of the plantarflexors can change secondary to the muscle weakness. Both effects seemed inde-pendent of the primary disease, at least to some extent. While the impact of muscle strength on the observed gait parameters cannot be neglected, spasticity seemed of minor importance. Therefore, muscle strength has to be taken into account when interpreting gait analysis data irrespective of the pathology. ---------- Zusammenfassung: Das bipedale Gehen ist für gesunde Menschen eine einfache und alltägliche Bewegung. Das Gangmuster von Patienten kann jedoch stark von einem gesunden Gang abweichen, vor allem bei Patienten mit neuro-muskulären Erkrankungen. Für den Kliniker ist es essentiell, zu unterscheiden, ob eine Gangbildabweichung primär oder sekundär ist, um mit Hilfe der Ganganalysedaten eine geeignete Behandlung einzuleiten. Primäre Gangbildabweichungen werden als ursächlich angesehen und erfordern eine Behandlung. Sekundäre Abweichungen hingegen bedürfen, unabhängig davon, ob ihnen eine aktive Kompensation oder ein passiver physikalischer Effekt zu Grunde liegen, keiner Therapie. Sie sollten sich zurückbilden, sobald die ursächliche körperliche Einschränkung behoben ist. Die Gangbilder von Patienten mit unterschiedlichsten Grunderkrankungen, z.B. Spastizität oder rein muskuloskeletalen Beeinträchtigungen, standen im Fokus dieser Arbeit. Das Ziel bestand darin, grundlegende Gesetzmäßigkeiten des krankhaften Gangs zu identifizieren. Diese Gesetzmäßigkeiten sollen in Zukunft die Unterscheidung zwischen primären und sekundären Gangbildabweichungen erleichtern. Mithilfe eines marker-basierten, dreidimensionalen Bewegungsanalyse-Systems (VICON) wurden Gangdaten der Patienten aufgezeichnet. Hiervon wurden hauptsächlich die kinematischen Gelenkwinkeldaten, elektromyographische Daten und Muskelkrafttests retrospektiv analysiert. Es wurde untersucht, ob und wie stark die Muskelkraft oder Orthesen Einfluss auf deren Gang haben, unabhängig von den Grunderkrankungen der Patienten. Zunächst wurde eine Methode entwickelt und evaluiert, welche einen charakteristischen Gangzyklus für einen Patienten automatisch detektiert (SMaRT). Der Algorithmus basiert auf einer Hauptkomponenten-Analyse (PCA). Er ermittelt denjenigen Versuch, welcher über alle Gelenkwinkel-Kurven im Mittel am nächsten am Median aller Versuche liegt. SMaRT evaluiert die Daten objektiv und kann dabei eine uneingeschränkte Retest-Reliabilität aufweisen. Gleichzeitig ist die Methode mit 1,4 s/100 Daten-Sets um mehr als drei Größenordnungen schneller als die visuelle Identifizierung durch Experten. Besonders hervorzuheben ist die kleine Fehlerrate von 1,2% bei der Detektierung des representativen Trials. SMaRT kann sowohl durch anderen Gang-Parameter, z.B. Gelenk-Momente oder Gelenk-Leistung, erweitert werden als auch auf anderen Bewegungsanalyse-Kurven, wie z.B. in der sportartspezifischen Bewegungsanalyse, angewendet werden. Alle Studien in dieser Arbeit basieren auf dem repräsentativen Gangzyklus, welcher für jeden Patienten individuell durch SMaRT ermittelt wurde. Für zwei weitere Studien wurden 716 Patienten anhand ihrer Erkrankungen in sieben Gruppen aufgeteilt: Orthopädische Patienten uni-/bilateral betroffen, neurologische Patienten uni-/bi-lateral betroffen mit hypotoner/spastischer Muskulatur mit/ohne Beeinträchtigung der Rumpfkontrolle. Ein negativer Effekt der Muskelkraft auf die Gelenkswinkel des Unterkörpers (Gait Profile Score, GPS) wurde mit der verallgemeinerten Methode der kleinsten Quadrate quantifiziert. Je schwächer die Patienten waren, umso stärker wich ihr GPS von der Norm nach oben ab. Die Stärke dieses Effekts unterschied sich in den sieben Patientengruppen nicht signifikant. Allerdings wurden zwischen den Gruppen bei einer normalen Muskelkraft signifikante GPS Unterschiede deutlich. Je höher der Schweregrad der Grunderkrankung, umso stärker war die Regressiongerade in Richtung eines höheren GPS parallel verschoben. Orthopädische Patienten sowie Patienten mit zerebralparetischer Hemiplegie zeigten GPS-Werte, welche sich im Bereich derer von Gesunden bewegten (orthopädisch unilateral: 4.9°±0.7, orthopädisch bilateral: 5.0°±1.0, Hemiplegie: 5.4°±1.1). Dahingegen wichen Patienten mit Diplegie, Tetraplegie oder bilateral hypotoner Muskulatur signifikant von der Norm ab. Überraschender Weise wurde bei Patienten mit Diplegie und Patienten mit bilateral hypotoner Muskulatur eine gleich hohe GPS Abweichung von der Referenzgruppe beobachtet. Selbst der Vergleich der einzelnen Gelenks-Parameter zeigte nur geringfügige Unterschiede zwischen den beiden Gruppen. Des Weiteren wurde eine Assoziation von Muskelkraft mit abnormer elektromyographischer Aktivität (EMG) gefunden, genauer gesagt mit verfrühter Plantarflexorenaktivität während der Gewichtsübernahme. Eine normale Muskelkraft reduzierte die verfrühte Gastrocnemius-aktivität um mehr als 10% über alle Patienten. Die Patientengruppe mit neurologischer Komponente und unilateral hypotoner Muskulatur stellte hier die einzige Ausnahme dar. Dies ist vermutlich auf die geringe Patientenzahl in dieser Gruppe zurückzuführen, welche eine Interpretation der Ergebnisse kaum zulässt. Auf Grund dessen, dass eine verfrühte Plantarflexorenaktivität in allen Patientengruppen auftrat, kann davon ausgegangen werden, dass diese Aktivität nicht nur durch die Grunderkrankung (z.B. Spastizität) hervorgerufen werden kann. Abschließend wurde untersucht, ob eine Änderung in der Unterkörperkinematik eine Adaption im Oberkörper hervorruft. Hierzu wurden bei hemiplegischen Patienten die Oberkörperbewegungen beim Gehen auf Zehenspitzen (barfuß) und beim Gehen mit Fersen-Ballen Gang (mit Orthese) verglichen. Zwischen den beiden Konditionen wurden jedoch keine klinisch relevanten Unterschiede in der Rumpfbewegung gefunden. Allerdings verstärkte der gesunde Arm die Armschwungamplitude, um den reduzierten Armschwung der plegischen Seite zu kompensieren. Schlussfolgernd kann festgehalten werden, dass die kinematische Änderung des sagittalen Sprunggelenkswinkels in den untersuchten Patienten nicht zu einer Normalisierung der Oberkörperbewegungen führten. Daher scheinen die verstärkten Oberkörperbewegungen nicht sekundäre Abweichungen zu sein, welche durch den Zehenspitzengang hervorgerufen werden. Anders verhalten sich hier die kinematischen Unterkörperabweichungen (Gait Profile Scores) und die verfrühte Plantarflexorenaktivität. Beide Abweichungen scheinen sekundär zu einer Muskelschwäche zu sein, was offenbar für alle Patientengruppen zutrifft. Während der Einfluss von Muskelkraft auf die untersuchten Gangparameter nicht unterschätzt werden darf, scheint die Spastizität das kinematische Gangbild geringfügiger zu beeinflussen. Bei der Interpretation von Ganganalysedaten sollte demnach die Muskelkraft immer beachtet werden, unabhängig davon welche Grunderkrankung der Patient aufweist

Kevin R Ford,1 Anh-Dung Nguyen,2 Steven L Dischiavi,1 Eric J Hegedus,1 Emma F Zuk,2 Jeffrey B Taylor11Department of Physical Therapy, High Point University, High Point, NC, USA; 2Department of Athletic Training, School of Health Sciences, High Point University, High Point, NC, USAAbstract: Deficits in proximal hip strength or neuromuscular control may lead to dynamic lower extremity valgus. Measures of dynamic lower extremity valgus have been previously shown to relate to increased risk of several knee pathologies, specifically anterior cruciate ligament ruptures and patellofemoral pain. Therefore, hip-focused interventions have gained considerable attention and been successful in addressing these knee pathologies. The purpose of the review was to identify and discuss hip-focused exercise interventions that aim to address dynamic lower extremity valgus. Previous electromyography, kinematics, and kinetics research support the use of targeted hip exercises with non-weight-bearing, controlled weight-bearing, functional exercise, and, to a lesser extent, dynamic exercises in reducing dynamic lower extremity valgus. Further studies should be developed to identify and understand the mechanistic relationship between optimized biomechanics during sports and hip-focused neuromuscular exercise interventions.Keywords: dynamic lower extremity valgus, hip neuromuscular control, ACL injury rehabilitation, patellofemoral pain, hip muscular activatio

Lower Extremity Balance as an Indicator of Upper Extremity Injury in Baseball Players: A Systematic Review Mower L, Ortman I, Murphy S. University of Montana Purpose: This review will seek to determine if a lack of lower limb balance can be a predisposing factor for elbow injuries in baseball players. Methods: We searched the database Pubmed on October 6th, 2021 using a combination of keywords baseball, UCL tears , UCL injur* , Tommy John , UCL sprain , elbow injur* , balance, lower extremity , kinetic chain , biomechanics, kinematics and throwing mechanics . The resulting articles were manually screened for relevance and inclusion/exclusion criteria. Articles were excluded if there were no special tests required, used female participants, or did not assess baseball specifically. Articles were included if the star excursion balance test or lower quarter y-balance test were assessed, participants consisting of baseball players, and elbow injuries. Studies identified by the search strategy were screened according to the inclusion criteria, and two reviewers assessed the data. Data extracted included the comparison of the average reach percentage of the lead leg and average reach percentage of the stance leg. Of the 133 articles identified through the initial database search, 4 studies were included in this review. Two articles assessed the Y-balance test while the other two articles assessed the star excursion balance test. Our observation for this systemic review assessed the overall balance findings from both subgroups. We then assessed the relationship between overall balance and elbow pathologies. This correlation was observed because elbow injuries and Tommy John surgeries are on a steady rise. Data is separated between the lead leg and stance leg in which the percentage of balance between injured and uninjured athletes can be visualized. The studies utilizing the Lower Quarter Y-Balance Test concluded athletes with lower balance percentages had a higher occurrence of elbow injuries. Studies utilizing the star excursion balance test concluded that athletes with higher percentages of balance capabilities were more likely to succumb to elbow pain. Originality: This systematic review demonstrated further understanding of the role of the kinetic chain is needed to find a definitive correlation among baseball players with a decreased level of dynamic balance and the presence of elbow injuries. While findings were contradictory to one another, clinicians can now assume proper throwing techniques, and balance programs should be employed in baseball strengthening programs for athletes to maximize their throwing velocity and decrease the risk of injury. Significance: This research provides a concise summary of the previous research completed that can be more easily used by clinicians. However, further research needs to be done in how we collect the lower extremity balance and its correlation to baseball throwing mechanics

The personalisation of footwear can be beneficial for different population groups, including older people, individuals with foot pathologies or abnormalities and runners. For runners in particular, footwear personalisation has the potential to offer four main advantages: optimum fit, improved comfort perception, improved performance (by altering lower limb alignment to reduce muscle activity) and reducing injury risk through personalisation of cushioning and support requirements. Additive manufacturing (AM) technology has potential for making footwear personalisation economically feasible due to its geometric freedom, tool-less capability and direct manufacture from CAD models. However, it is not known how personalised footwear affects discomfort and biomechanics following short and medium term use. The main objective of this research was to evaluate the short and medium term use of personalised insoles in terms of discomfort and lower extremity biomechanics