Thesis (MScSportSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Neuromuscular control (NMC) plays a critical role in dynamic movement regulation such as running (Nyland et al., 2011) and injury prevention (Hübcher et al., 2010). This experimental study set out to determine whether an eight-week minimalist shoe training program influences NMC in recreational distance runners. Eleven experimental (EXP) (5 women; 6 men) (age 23.4 ± 2.98 yrs; VO2max 43.55 ± 5.04 ml.min-1.kg-1; BMI 22.61 ± 3.08 kg.m2; Training 17 ± 5km.w-1) and 12 control (CON) runners (7 women; 5 men) (age 25.42 ± 5.57 yrs; VO2max 43.67 ± 4.38 ml.min-1.kg-1; BMI 22.38 ± 3.12 kg.m2; Training 18 ± 6km.w-1) randomly completed an eight-week training program in either minimalist shoe (EXP) or their usual trainers (CON). Neuromuscular control components were measured before and after the intervention i.e. postural sway (Balance Biodex®), using the Athletic Single Leg (ASL) and modified Clinical Test of Sensory Integration and Balance (mCTSIB) tests, joint position sense (JPS) using joint angle reproduction tests (Biodex® Isokinetic Dynamometer), frontal and sagittal planes isokinetic strength testing, lower body electromyography (EMG) and kinematic measurements while participants ran on a treadmill. Plantar-dorsiflexion (PF/DF) or inversion eversion (IN/EV) proprioception did not differ between groups (p > 0.05). In selected trials EXP showed less deterioration in IN/ EV foot position error, when compared to CON, with medium to large practical significance. Athletic Single Leg scores for non-dominant (p < 0.01) and dominant M/L (p = 0.05) sway, and dominant overall sway (p = 0.04) improved in CON, with marked differences between genders. Dorsiflexor strength improved for 30∘.sec-1 and 60∘.sec-1speeds in CON (p < 0.01 & p = 0.04, respectively) and in the slower speed for EXP (p = 0.04). Plantar-flexion (PF) strength improved in EXP men (30∘.sec-1 p = 0.02; 60∘.sec-1 p = 0.02), while EXP women demonstrated a 7% deficit. At initial contact PF increased in EXP (8km.h-1 p = 0.01; 10km.h-1 p = 0.01; 12km.h-1 p = 0.01), with women showing a greater change in ankle angle (8km.h-1 p = 0.03; 10km.h-1 p = 0.02; 12km.h-1 p = 0.01) compared to men (8km.h-1 p = 0.05; 10km.h-1 p = 0.06; 12km.h-1 p = 0.05). Greater knee flexion (8km.h-1 ES = 0.64; 10km.h-1 ES = 0.49; 12 km.h-1 ES = 0.51) in EXP. Plantar-flexor pre-activation improved in EXP women, while co-activation improved in EXP men and total activation improved in both genders.Results suggest that women may require more time to transition into minimalist shoes. While minimalist shoes may moderately reduce foot position error, improve strength and muscle activation patterns, excessive plantar flexor muscle damage may reduce strength and muscle spindle proprioceptive feedback. / AFRIKAANSE OPSOMMING: Neuromuskulêre beheer (NMC) speel ‘n kritieke rol in dinamiese beweginsregulasie, soos met hardloop (Nyland et al., 2011) en beseringsvoorkoming (Hübscher et al., 2010). Hierdie eksperimentele studie het uit gesit om te bepaal of ‘n agt-week minimalistiese skoen oefenprogram NMB kan beïnvloed in rekreasie langafstand atlete. Elf eksperimentele (EXP) (5 vrouens, 6 mans) (ouderdom 23.4 ± 2.98 jr; VO2maks 43.55 ± 5.04 ml.min-1.kg-1; BMI 22.61 ± 3.08 kg.m2; Oefening 17 ± 5km.w-1) en twaalf kontrole (CON) hardlopers (7 vrouens, 5 mans) (ouderdom 25.42 ± 5.57; VO2maks 43.67 ± 4.38 ml.min-1.kg-1; BMI 22.38 ± 3.12 kg.m2; Oefening 18 ± 6 km.w-1) het lukraak ‘n agt-week oefenprogram voltooi, óf in minimalistiese skoene (EXP) of in hul gewone hardlooptekkies (CON). Neuromuskulêre beheer komponente was gemeet voor en na die intervensie i. e. posturale wieg (Balans Biodex®), met gebruik van Atletiese Enkelbeentoets (ASL) en die gemodifiseerde Kliniese Toets van Sensoriese Integrasie en Balans (mCTSIB), gewrigs posisie bewustheid (Biodex® Isokinetiese Dinamometer), frontale en sagitalle vlak isokinetiese kragtoetsing, onderlyf elektromiografie (EMG) en biomeganiese metings terwyl deelnemers op ‘n trapmeul gehardloop het. Plantaar dorsifleksie (PF/DF) of inversie eversie (IN/EV) propriosepsie het nie verskil tussen groepe nie (p > 0.05). In selektiewe proewe het EXP IN/ EV ‘n verminderde afname gehad in foutiewe voet posisieplasings, in vergelyking met CON, terwyl medium na groot praktiese betekenisvolle verskille. . Atleet enkel been toets tellings vir nie-dominant (p=0.001) en dominante M/L (p = 0.05) wieg, en dominant algehele wieg (p = 0.04) het verbeter in CON, met gemerkte verskille tussen geslagte. Dorsifleksor krag het verbeter vir 30∘.sec-1 en 60∘.sec-1spoed in CON (p = 0.01 en p = 0.04, onderskeidelik) en in die stadiger spoed vir EXP (p = 0.04). Plantaarfleksie (PF) krag het verbeter in EXP mans (30∘.sek-1 p = 0.02; 60∘.sek-1 p = 0.02), terwyl EXP vrouens ‘n 7% tekort gedemonstreer het. By initïele kontak het PF toegeneem in EXP (8km.h-1 p = 0.01; 10km.h-1 p = 0.01; 12km.h-1 p = 0.01), met vrouens wat ‘n groter verandering getoon het (8km.h-1 p = 0.03; 10km.h-1 p = 0.02; 12km.h-1 p = 0.01), in vergelyking met mans (8km.h-1 p = 0.05; 10km.h-1 p = 0.06; 12km.h-1 p = 0.05). Groter kniefleksie (8km.h-1 ES = 0.64; 10km.h-1 ES = 0.49; 12 km.h-1 ES = 0.51) in EXP. Plantaarfleksie pre-aktivering het verbeter in EXP vrouens, terwyl ko-aktivering verbeter het in EXP mans, en totale aktivering verbeter het in beide geslagte.Hierdie resultate stel voor dat vrouens moontlik meer tyd sal vereis om na minimalistiese skoene oor te skakel. Terwyl minimalistiese skoene matige verbetering in foutiewe voetposisieplasing, verbeterde krag en spieraktiveringspatrone kan veroorsaak, kan oormatige plantaarfleksie spierskade krag en spierspoel proprioseptiewe terugvoer ook verminder.

The purpose of this study was to determine if prophylactic ankle tape and/or ankle braces improve dynamic stability in TTS measure. All subjects were healthy and had no prior history of ankle injuries. Data collection consisted of each subject performing a single leg jump-landing with ankle tape, ankle brace, combination of the two, and control (no tape or brace) conditions. Dynamic stability was assessed with time to stabilization force plate measure. Significant plane by ankle tape interaction (p=0.045) was found. No significant plane by ankle tape by ankle brace interaction (p=0.637), no significant ankle tape by ankle brace interaction (p=0.483), or plane by ankle brace interaction (p=0.697) were found. A notable finding was that subjects took longer to stabilize in the anterior/posterior direction than medial/lateral direction. In conclusion ankle tape, ankle brace, and the combination of ankle tape and ankle brace did not statistically improve dynamic stability in healthy ankles.

Bakgrund:  Simning är en populär sport. De extrema repetitiva rörelserna som ingår i sporter med majoriteten av rörelserna över huvudet, som exempelvis simning, och otillräcklig stabilitet i axelleden resulterar ofta i överansträngning och skador. Ett vanligt syndrom är impingement och det har rapporterats att 40-91 % av alla simmare har eller upplever problem i axelleden eller de omkringliggande strukturerna. Syfte: Att undersöka om en intervention bestående av övningar för scapulas närliggande muskler i fyra veckor kan påverka upplevd smärta i axel och nacke hos unga simmare. Deltagare: Sexton unga simmare mellan åldrarna (13±2), bestående av (10 flickor och 6 pojkar) deltog. Alla deltagare utförde minst fyra simpass i veckan. Alla deltagare i studien upplever problematik i axel och/eller nacke. Metod: Deltagarna fick fylla i ett (SRQ-S) formulär och genomgå ett Beighton-test. Alla deltagare instruerades i fyra olika övningar, syftet med övningarna var att öka neuromuskulär kontroll och styrka i axelns stabiliserande muskler. Alla övningar skulle utföras innan träningspass, minst en gång om dagen, i fyra veckor. Efter fyra veckors interventionen fick deltagarna fylla i ett nytt (SRQ-S) formulär, den totala poängen innan och efter jämfördes. Resultat:  (SRQ-S) formulären resulterade i en signifikant skillnad (p=0,0005) mellan innan och efter interventionen. Majoriteten av deltagarna rapporterade ett högre välmående i axel och/eller nacke. Konklusion : Majoriteten av deltagarna upplevde minskad problematik i axel och/eller nacke efter fyra veckors interventionen. Det visar på att det finns ett samband mellan ökad axel stabilisering och minskad upplevd smärta i axel/nacke. Dock kan denna studie inte komma till en säker konklusion då vidare undersökning måste göras i detta område. / Background : Competitive swimming is a popular sport. The extreme repetitive motions that overhead-sports implies, like swimming, and inadequate stability in the shoulder joint often results in overexertions and injuries. A common condition is impingement syndrome and it has been reported that 40-91% of all swimmers have or experience problems in the shoulder joint or in the surrounding structures. Purpose : To investigate whether an intervention consisting of exercises for scapulas nearby muscles for four weeks can affect perceived distress in the shoulders and neck of young swimmers. Participants : Sixteen young swimmer between the age of (13±2), consisting of (10 females and 6 males) volunteered to participate. All the participants are performing at least four sessions of swimming a week. All the participants in the study are experiencing trouble in their neck or/and shoulders. Method : The participants had to fill in a (SRQ-S) form and do a Beighton-test. Participants were instructed in four different exercises, the purpose of the exercises were to increase neuromuscular control and strength in the shoulder stabilizing muscles. All exercise were to be performed before every session of swimming, at least once a day, for four weeks. After the four weeks of intervention the participants had to fill in a new (SRQ-S) form, the before and after score were compared. Results : The (SRQ-S) formulas resulted in a significant difference (p=0,0005) between before and after the intervention. The majority of the participants reported also a higher prosperous in their shoulder and/or neck area. Conclusion: The majority of the participant experienced less discomfort in their shoulder and neck area after the four weeks of intervention. There seems to be a relationship between increased shoulder stability and decrease in discomfort in the shoulder/neck. However this study can not come to a secure conclusion and further investigation has to be made in this area.

Tendinopathien der Achilles- oder Patellarsehne sind häufig in Sportarten mit zahlreichen repetitiven Belastungen im Dehnungs-Verkürzungs-Zyklus der unteren Extremität zu finden. Sowohl eine möglicherweise alterierte belastungsspezifische neuromuskuläre Antwort (NMA), als auch funktional begründete Therapiemaßnahmen mit möglichen positiven Effekten sind aktuell ungeklärt. Ziel der Arbeit war deshalb die Untersuchung der belastungsspezifischen neuromuskulären Antwort bei Athleten mit Tendinopathie der Achilles- oder Patellarsehne im Vergleich zu beschwerdefreien Athleten. Zusätzlich sollten mögliche funktionale und therapeutische Effekte eines sensomotorischen Trainings im randomisierten, kontrollierten und prospektiven Studiendesign überprüft werden. 51 Sportler mit unilateraler Tendinopathie (Achilles-/Patellarsehne n = 35/16) und 33 gesunde Sportler wurden zur Beurteilung der belastungsspezifischen neuromuskulären Antwort eingeschlossen. Zur Klärung der Effekte eines sensomotorischen Trainings im Längsschnitt konnten 26 Sportler mit Tendinopathie randomisiert zu einer Kontrollgruppe (n = 14) und einer Therapiegruppe mit sensomotorischem Training (n = 12) zugeordnet werden. Nach einer ersten biomechanischen Messung M1 (Belastungssituationen: Lauf-, Stabilisations-, Kraftbelastung) und der Erhebung der subjektiven Schmerzsymptomatik folgte eine 8-wöchige Therapiephase mit einer abschließenden Re-Test-Messung M2 identisch zu M1. Das sensomotorische Training war auf die gesamte untere Extremität ausgerichtet und wurde nach Einweisung regelmäßig kontrolliert. Die Erfassung der NMA erfolgte über die Quantifizierung der muskulären Aktivität (EMG). Zusätzlich wurde die Kinetik (z.B. Maximalkraft) belastungsspezifisch erfasst. Eine reduzierte NMA konnte für die Sportler mit Tendinopathie über veränderte EMG-Zeit- und Amplitudenmessgrößen, eine reduzierte aktive Stabilisationsfähigkeit und Maximalkraft (p < 0,05) nachgewiesen werden. In Abhängigkeit der Lokalisation (Achilles-/Patellarsehen) bzw. der Seite (Beschwerdeseite/gesunde Seite) ergaben sich keine relevanten Differenzen. Das sensomotorische Training zeigte eine Optimierung der NMA (z.B. erhöhte Maximalkraft) bei Tendinopathie der Achilles- oder Patellarsehne. Die Überprüfung der Beschwerdesymptomatik wies in allen Schmerz-Scores nach der Therapie reduzierte Werte und damit einen positiven therapeutischen Effekt gegenüber der Kontrollgruppe auf. Zusammenfassend kann eine systematisch reduzierte NMA bei Lauf-, Stabilisations- und Kraftbelastung der Sportler mit Tendinopathie nachgewiesen werden. Das sensomotorische Training ist funktional und therapeutisch als effiziente Therapiemaßnahme zu erachten. / Tendinopathies of the achilles- or patellartendon are common overuse unjuries in sports including high numbers of repetitive stretch-shortening-cycles of the lower limb. Possible alterations of the neuromuscular response (NMR) to physical stress and functionally justified therapies with potential positive effects are currently unknown. The aim of the study was therefore the analysis of the neuromuscular response in situations with physical stress in athletes with tendinopathie of the achilles or patellartendon compared to symptom free athletes. In addition, possible functional and therapeutic effects of a sensorimotor training were studied in a prospective, randomized and controlled study. 51 athletes with unilateral tendinopathy (achilles-/patellartendon n = 35/16) and 33 healthy athletes were included to assess the stress related neuromuscular response (NMR). To clarify the effects of a sensorimotor training 26 athletes with tendinopathy were randomized to a control group (n = 14) and a therapy group with sensorimotor training (n = 12). After initial biomechanical measurements M1 (situations: running, active postural stability and maximum strength test) and the collection of subjective complaints (pain) an 8-week treatment phase followed with a final re-test M2 measure identical to M1. The sensorimotor training was arranged for the entire lower extremity, and was checked after an initial briefing on a regular basis. The assessment of the NMR was quantified by muscle activity (EMG). In addition, the kinetics (e.g. maximum force) was acquired in the stabilization and maximum strength test. A reduced NMR could be proven for athletes with tendinopathy with changed EMG time and amplitude measurements, a reduced active postural stabilization ability and reduced maximum strength (p <0.05). No relevant differences could be observed in comparing localization (achilles-/patellartendon) and side (leg with complains/healthy leg). The sensorimotor training showed an optimization of NMR (e.g. increased maximum strength) for patient with tendinopathy of the achilles- or patellartendon. The examination of the complaints showed reduced values in all pain scores after therapy. The treatment had therefore positive therapeutic effects compared to the control group. In summary, a systematically reduced NMR in running, stabilization and strength tests are evident for athletes with tendinopathy. The sensorimotor training can be considered as an efficient treatment with functional and therapeutic effects.

Purpose: Adolescents have significantly higher rates of diagnosed anterior cruciate ligament (ACL) injuries compared to adult cohorts. Approximately two-thirds of ACL injuries are non-contact scenarios that occur while performing “high-risk” maneuvers. Less than 50% of adolescents are able to return-to-activity, with females specifically having a lower activity level post-injury (Hewett, Di Stasi, & Myer, 2013; Schmale, Kweon, Larson, & Bompadre, 2014). Identifying the quantitative demand of a task used to assess return-to-activity will help establish its role in evaluating the knee stabilization strategies based on muscular coactivations and biomechanical outputs. Therefore, the aim of this study was to (1) assess the neuromuscular and biomechanical quantitative outputs of the lunge and drop-vertical jump (DVJ) in healthy adolescent male and females athletes and (2) to examine the muscular coactivation strategies of adolescent male and female athletes with and without an ACL injury. Methods: A total of 68 uninjured adolescent male and female athletes between the ages of 10 to-18 were used to identify the quantitative demand of the lunge and DVJ. Neuromuscular and biomechanical quantitative outputs included mean peak knee flexion (PKF), integrated knee excursion (iKEXC) in the sagittal and frontal planes, integrated knee joint power (iJP), and integrated electromyography (EMG) were used to assess the within (task) and between (sex) interactions. An additional 17 male and 37 female adolescents with an ACL injury were included to assess the impact of an ACL injury on the knee stabilization strategies (coactivations) used to maintain dynamic knee joint stability (frontal plane knee excursion). Ethics was approved by the University of Ottawa Research Ethics Board (uOttawa REB H09/17/10) (CHEO REB 17/74X). Results: Quantitative data for uninjured groups indicated that the lunge produced greater peak knee flexion, knee excursion, and quadriceps activation values than the DVJ. Conversely, the DVJ produced greater joint power, biceps femoris, gastrocnemii, and gluteus medius values. As for knee stabilization strategies, during the DVJ female ACL injured groups produced greater symmetry and higher muscular activations between anterior-posterior and medial-lateral muscular coactivations, which resulted in increased stability compared to uninjured female groups. Males with an ACL injury indicated similar knee stabilization strategies however decreased stability compared to males without an ACL injury. Conclusion: Results of this thesis identified differences in quantitative data between the lunge and DVJ, indicating differing demand requirements for each task. Results of the second study indicate that uninjured females use knee stabilization strategies that do not restrict their degrees of freedom through asymmetrical coactivations, while females with an ACL injury have increased coactivations in both anterior-posterior and medial-lateral muscle groups, resulting in increased dynamic knee joint stability as evidenced by reduced frontal plane knee excursion motion. Males, however, failed to show a difference between groups in dynamic knee stability, suggesting that those with an ACL injury compensated in a way to perform the DVJ efficiently and similarly to the uninjured group, while maintaining dynamic knee joint stability. In a clinical setting, these findings may help in understanding the direction of use of the lunge and DVJ tasks in a rehabilitation setting. As well as provide insight into the differing male and female adolescent knee stabilization strategies used to maintain dynamic knee joint stability during functional tasks.

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In dieser Arbeit wird die Physik der Stimm- und Lautbildung von Vögeln untersucht, wobei zwei verschiedene Zwei-Massen-Modelle des menschlichen Kehlkopfes, sowie die Theorie der Nichtlinearen Dynamik verwendet werden. Die Zwei-Massen-Modelle des menschlichen Kehlkopfes (ein angepasstes Zwei-Massen-Modell und ein Trapez-Modell) wurden dazu an die Größe des Stimmorgans der Vögel (Syrinx) angepasst, um die Druckentstehung, die Steuerung der harmonischen Obertöne und "Register" studieren zu können, die vom Syrinx ohne Kopplung an Quelle und Vokaltrakt erzeugt werden. Unsere Simulationen sind ein erster Schritt in Richtung eines realistischeren Modells der Syrinx. Eine detaillierte Bifurkationsanalyse des Trapezmodells bestätigt, dass die Geometrie und die Ruhelage der Syrinx das harmonische Spektrum drastisch beeinflussen können, und sie gibt Hinweise über mögliche Erzeugungsmechanismen der reichhaltigen harmonischen Spektren während der Einatmung. Des weiteren wird die Bifurkationsanalyse benutzt, um den Beitrag der Muskeln der Syrinx quantitativ zu beschreiben. Dies geschieht in dem Modell mit Hilfe von zeitabhängigen Parametern, welche die Ruhelage der Labia und die Frequenzmodulation steuern. / In this thesis, the physics of birds phonation is discussed using a two-mass models approach and the theory of nonlinear dynamics. Two-mass models of the human larynx (rescaled two-mass model and trapezoidal model) have been adapted to the dimension of the avian syrinx to study pressure onset, control of harmonic overtones and "registers" of the sound radiated by the birds vocal organ (syrinx) in the absence of source-tract coupling. Our simulations are a first step towards more realistic modelling of the syrinx. A detailed bifurcation analysis of the trapezoidal model confirms that the geometry and the rest position of the syrinx can influence the harmonic spectra drastically, suggests possible mechanisms involved in the production of rich-harmonic spectra during inspiration and is used to describe quantitatively the contribution of syringeal muscles. The latter is implemented in the model by means of driving time-dependent parameters controlling the labia rest position and frequency modulation.