Repeat sprint ability has been investigated thoroughly, however optimal training methodology to improve RSA remains elusive. Both kinetic and physiological viewpoints have been used to scrutinize aspects of RSA including, initial sprint performance (anaerobic power), maximal cardiorespiratory fitness (VO2max), lactate threshold, anaerobic capacity (mean power), muscle activation (EMG), and local muscle oxygenation kinetics. To our knowledge no study has utilized maximal strength levels as a separate factor among a homogenous group of cardiorespiratory fitness individuals (as determined by peak VO2 during RSA). The purpose of this study was to better understand the relationship between maximal strength, muscular characteristics, and cycling RSA- respective to muscle oxygenation responses. Fifteen participants completed fifteen 10-second maximal effort sprints on a cycle ergometer interspersed with 30-seconds passive recovery. Respiratory, muscle oxygenation, and kinetic responses were monitored continuously and evaluated relationships with maximal strength and muscular architecture as determined by isometric mid-thigh pull and ultrasonography respectively. A series of 2 x 15 mixed design, group x time, ANOVA’s were used to evaluate the effects of group and or sprint on muscle oxygenation kinetics. Strong individuals were found to have significantly greater levels of muscle oxygenation usage, recovery and the respective rates; p = 0.01, p = 0.02, p

The purpose of this study was to examine the differences in technique between sprinters and baseball players while running at maximal speeds. 20 male NCAA Division I athletes participated; ten members of the track and field team specializing in the 100 m or 200 m sprint or the 100 m hurdles and ten members of the baseball team. Each subject performed a maximal effort 80 m sprint while their sprint times were recorded every 10 m starting at the 20 m mark. Each subject was filmed at they ran through a set10 m marking that included where they reached their top speed allowing the camera to capture at least one complete stride. By using the Peak Motus System, each subject's minimum knee flexion, minimum hip angle, knee extension at toe off, contact time, stride length, center of mass at touchdown and shank angle were measured. ANOVA with repeated measures found that sprinters and baseball players display significant differences in their sprinting technique in all variables except shank angle with the sprinters displaying a shorter 10 m split time. It was concluded that proper sprint training during baseball practice could prove to be beneficial to baseball players, however, further research would need to be conducted to support this claim.

Objectives. Evaluate C-reactive protein (CRP) levels according to weight and physical activity. The study explored how changes in CRP were associated with baseline CRP, weight, and physical activity and changes in these variables. Methods. A randomized controlled study design assigned 348 individuals to the intervention or control group with measurements taken at baseline, 6 weeks, and 6 months of body weight, physical activity, and serum CRP levels. Participants attended an intensive 40-hour educational course delivered over a four-week period. Results. At baseline, CRP was negatively associated with total steps/week, and positively associated with weight, BMI, percent fat, and saturated fat at baseline. CRP significantly decreased through 6 weeks and also through 6 months for only those with high CRP at baseline. For those with high CRP at baseline, the decrease was significant for normal, overweight, and obese groups of people. Changes in weight or physical activity were not significantly associated with changes in CRP. Conclusions. Over 6 week and 6 month follow-up periods, the intervention failed to discriminate changes in CRP. Changes in CRP were only associated with baseline levels of CRP and BMI and were not associated with changes in any of the selected variables considered.

The purpose of this study was to determine if motivational profiles of individual collegiate team sport athletes differ across ability levels (High, Middle, and Low) and settings (Team Practice, Competition, and Personal Practice). The athletes task and ego disposition, autonomy, and contextual motivation, were assessed using the Perception of Success Questionnaire (POSQ), Sport Climate Questionnaire (SCQ), and Sport Motivational Scale (SMS), pre and postseason. Their anxiety levels and situational motivation were measured using the Sport Anxiety Scale (SAS) and the Situational Motivational Scale (SIMS) during the season. The General Causality Orientations Scale (GCOS) was used pre and postseason to assess the strength of different motivational orientations in the coaches and the strength of association to the athletes' various motivational, anxiety and dispositional profiles. Results revealed that the athletes are functioning with high task and ego orientations almost equally across settings. They were also relatively high overall in perceived autonomy support. Anxiety and worry existed in all three settings, but in only low to moderate amounts. In addition, athletes reported higher levels of concentration disruption in competition settings over team or personal practice. Finally, individual athletes experienced significantly higher levels of self-determination behavior in both the competition and personal practice settings over team practice. No significant differences were found between the pre and postseason surveys for either the athletes or the coaches, or in the ability levels (H, M, and L) of the athletes.

Introduction: Maximum running acceleration essential components in many sports. The identification of specific training protocols to maximize sprint speed would be useful knowledge for soccer coaches and players. Purpose: The purpose of this study was to determine the effect of a high-speed treadmill with the use of a body-weight support system in a 6-week sport acceleration program on: 40-yard sprint time, maximal isometric knee flexor and extensor strength. Methods: 32 female soccer players (age 16 ± 1.19 yrs) participated in two treatment groups and one control group. Both treatment groups participated in a 12-session sport acceleration program. The first treatment group utilized a body-weight support system while on a high-speed treadmill; the second group used a standard treadmill with no body weight support system. The control group, NT, did not participate in a sports acceleration program and did not alter their exercise routines outside of the study. Results: For each variable an Analysis of Covariance (ANCOVA) was performed. 40-yard sprint times for treatment groups were shown to improve significantly as compared to the control group (p = 0.0007 for high-speed treadmill with body-weight support system, p= < 0.0001 for standard treadmill without body-weight support system). Isometric flexor and extensor strengths did not show significant differences between treatment groups and control group. P-values for the high-speed with body-weight support system were (p = 0.53) for flexors and (p = 0.51) for extensors as compared to the control group. P-values for the standard treadmill with no body-weight support system were (p = 0.19) for extensors and (p = 0.0263) for flexors. It is noted that the extensor muscles were nearly significant for the standard treadmill with no body-weight support system. Discussion: These results can help high school coaches and athletes determine the optimal treadmill training regime. The current study shows that a high-speed treadmill with body-weight support system is just as beneficial as standard treadmill training.

<p>It is well established that physical activity can improve aspects of physical fitness in individuals with spinal cord injury (SCI). Despite reports of declining health and fitness post-discharge from rehabilitation, there is a limited amount of research exploring exercise status or interventions during this period. The purpose of this dissertation was to investigate the integration of structured exercise into the rehabilitation process following SCI, and to optimize the exercise prescription in the community setting. Findings from the first study indicated that exercise is well tolerated among individuals with sub-acute SCI; performance of a peak exercise test on an arm ergometer was feasible for all injury types. At this stage post-injury, interventions should be mindful of the greater risk of orthostatic intolerance in individuals with complete tetraplegia and focus on building task specific self-efficacy. The second study involved a direct referral and physical activity counselling intervention post-discharge. Adherence rates were excellent among those participants who received the intervention suggesting that this model of care can facilitate adherence to community exercise after discharge.</p> <p>The final two studies took place in the community. Several modes of adapted exercise were compared and findings indicated that while there were no differences in measures of physiological intensity or enjoyment between the different modes, arm-only exercise was perceived as safer than passive hybrid (arm and leg) exercise. Further, the validity of using ratings of perceived exertion (RPE) to attain prescribed exercise intensity was established. The efficacy of the physical activity guidelines for improving fitness in adults with SCI were evaluated in a community-based randomized controlled trial and the results revealed that the guidelines were effective in improving both aerobic capacity and muscle strength. Taken together, this series of studies describes a model of care that links rehabilitation with community exercise and suggests options for sustained engagement.</p> / Doctor of Philosophy (PhD)

INTRODUCTION: Sarcopenia is a loss of muscle function and muscle mass which frequently occurs among the oldest-old adult population (aged 85+ years). The analysis of accelerometer-determined physical behavior volumes and patterns of oldest-old adults might provide novel insights into the associations with sarcopenia and its components. METHODS: A total of 145 participants in the primary sample and 87 participants in the subsample with a mean age of 88.2 (2.5) years from the Health, Aging, and Body Composition study cohort provided cross-sectional data of handgrip strength, appendicular lean mass, gait speed, and accelerometry. Probable, confirmed, and severe sarcopenia were assessed based on the revised definition of the European Working Group on Sarcopenia in Older People 2. Binomial logistic and multivariate linear regression models as well as dose-response analyses were applied and adjusted for demographics, accelerometer wear time, lifestyle factors, and chronic health conditions. RESULTS: Oldest-old adults with higher total volumes of moderate to vigorous physical activity (MVPA) (OR=0.74, 95% CI 0.62 to 0.89) showed a lower likelihood for a probable sarcopenic condition in the primary sample. Likewise, patterns of higher accumulated time spent in MVPA bouts of less than 10 minutes (OR=0.78, 95% CI 0.64 to 0.95) and MVPA bouts of at least 10 minutes (OR=0.78, 95% CI 0.63 to 0.98) were also related with lower odds of probable sarcopenia. A 2.1 times (95% CI 1.01 to 4.35) higher likelihood for confirmed sarcopenia was observed among participants who spent 60 minutes more per day in sedentary behavior (SB). Furthermore, 2.9 times (95% CI 1.05 to 8.02) greater odds of severe sarcopenia were identified following each 0.1 higher active-to-sedentary transition probability (ASTP). Focusing on individual sarcopenic components, higher total activity counts, higher MVPA, higher light intensity physical activity (LIPA), lower SB, and lower ASTP were related with better gait speed. CONCLUSION: The total volume of MVPA, whether accumulated in short sporadic bouts or prolonged bouts, was associated with lower odds of probable sarcopenia. Higher LIPA, lower SB, and a less fragmented activity pattern might also be related with a lower likelihood of sarcopenia status and better physical performance among oldest-old adults.

INTRODUCTION: Cerebral Palsy (CP) is a sensorimotor disorder characterized by dysfunctional motor coordination, balance problems, and loss of selective motor control. Motor coordination exhibited as co-contraction, has been subjectively quantified using gait analysis, but recent studies have begun to objectively analyze the amount of co-contraction by collecting electromyography (EMG) data. Center of pressure excursion (COPE) measurements collected during a single leg standing test (SLST) have shown to be more valid measurements of balance in populations with motor disabilities than a SLST alone. A recent study has correlated increased COPE velocity with a lower fall risk as determined by reported fall frequency, suggesting a more objective measure of fall risk. The current study aimed to determine if the fall risk calculated by COPE velocity in children with CP is correlated with co-contraction index value in various muscle synergy groups. It was hypothesized that i) co-contraction index values will differ between high and low fall risk groups, ii) there will be preferential activation of different synergy groups within the high and low fall risk groups, and iii) there will be a negative and direct correlation between COPE velocity and co-contraction index values for all synergy groups. METHODS: Fall risk grouping was determined by average COPE velocity values calculated from previously reported fall frequency groups. Balance ability was determined by COPE measurements during a SLST on a force plate. Muscle synergy groups were determined by common muscle pairings at the hip, knee and ankle. Co-contraction indices were determined from linear envelopes plotted from muscle group EMG data. An independent t-test was run on muscle synergy groups between high and low fall risk groups. Nonparametric Analysis of Variance (ANOVA) and Tukey post-hoc tests were run on the high and low fall risk groups separately to determine differences in co-contraction index value within high and low fall risk groups. A Pearson correlation analyzed COPE velocity and co-contraction index value. RESULTS: No significant differences in muscle synergy between the high and low fall risk groups were found (p = 0.476, 0.076, 0.064, 0.364). The ANOVA and Tukey post-hoc tests for high fall risk group found significant differences in co-activation index value between the sagittal hip and frontal hip groups (p = 0.022) and sagittal hip and ankle groups (p = 0.016). Low fall risk group was found to have significant differences between the sagittal hip and frontal hip groups (p = 0.038) and frontal hip and knee groups (p = 0.012). Weak and negative correlations were found between COPE velocity and both knee and ankle groups (r = -0.309, -0.323, p = 0.059, 0.050). Negligible and insignificant correlations were found between frontal hip and sagittal hip synergies and COPE velocity ((r = 0.013, -0.068, p = 0.475, 0.367). CONCLUSION: There is insufficient evidence to claim that muscle group activations are different depending on fall risk grouped by COPE velocity. It is not currently possible to correlate COPE velocity to a specific synergy group recruitment. However, data do suggest that sagittal hip and knee strategies are recruited more than ankle and frontal hip strategies during SLST.

Um die Effektivität der Sporttherapie insbesondere im Rahmen der medizinischen Trainingstherapie zu erhöhen, müssen nach Sportverletzungen wie die vordere Kreuzbandruptur besondere Anforderungen an die Therapie gesetzt werden. Gründe sind die vom Kostenträger determinierte Rehabilitationszeit und eine anzustrebende komplikationslose sportliche Aktivität nach der Rehabilitation des Sportlers. Eine mögliche Alternative stellen offene kinetische Systeme dar. Diesen wird jedoch eine zu hohe Beanspruchung für das frische Transplantat unterstellt. Ziel war es, die Wirkung des offenen und des geschlossenen Systems im rehabilitativen Krafttraining an Patienten nach VKP zu untersuchen. Dazu wurden 34 Patienten (Alter 30 ± 9,9 Jahre, Gewicht 75,9 ± 13,2 kg, Größe 178,5 ± 5,5 cm) in eine randomisiert zweischenklige Trainingsstudie unter realen klinischen Bedingungen eingeschlossen (N=17 je Gruppe). Zur Überprüfung der Wirkung der Trainingstherapie wurden ein Isokinet (120°/s), Lachmanntest mittels Rolimeter sowie manuelle Umfangsmessungen jeweils vor und am Ende der Rehabilitation eingesetzt. Die Ergebnisse zeigten signifikanten Kraftzunahmen der Knie-Extensoren und Flexoren (p<0,05) in beiden Gruppen. Zwischen beiden Gruppen lagen keine signifikanten Unterschiede im Ausmaß der Entwicklung der Kraftfähigkeiten vor (p>0,05). Die vorderen Schubladen blieben bei beiden Trainingsgruppen unverändert (p>0,05). Die Befunde zeigen, dass möglicherweise das offene kinetische System im rehabilitativen Krafttraining eine sinnvolle Ergänzung darstellen kann. / To increase the effectiveness of sports therapy particularly in the context of medical training therapy, must be put in the treatment of sports injuries such as anterior cruciate ligament special requirements. Reasons are the cost of carrier-determined rehabilitation time and a desirable complication-free sporting activity for the rehabilitation of the athlete. A possible alternative are open kinetic systems but it is deemed too high a load for the fresh graft assumed. The aim, the effect of the open and the closed system was examined in the rehabilitative strength training in patients after retail price. These were 34 patients (age 30 ± 9.9 years, weight 75.9 ± 13.2 kg, 178.5 ± 5.5 cm size) were enrolled in a randomized study with two groups under real clinical conditions. To check the effects of exercise therapy were used with an isokinetic (120 ° / s), Lachmann test using Rolimeter and manual volume measurements before and at the end of rehabilitation. The results showed significant increases in strength of knee extensors and flexors (p <0.05) in both groups. Between two groups were not significantly different in the degree of development of strength abilities before (p> 0.05). The laxity of LCA remained unchanged in both training groups (p> 0.05). The findings show that potentially, the open kinetic system in rehabilitative strength training be a useful addition.

This systematic review investigates the biomechanical risk factors associated with femoroacetabular impingement (FAI) in female athletes. Using a particular methodology, the review synthesizes relevant sources to comprehensively analyze multi-factorial contributions to FAI, including load distribution, forces, strain, and sport-related mechanisms. By critically evaluating existing literature, this study aimed to provide a nuanced understanding of the intricate biomechanical aspects influencing the development of FAI in female athletes. A thorough examination of the literature encompassed articles spanning the years 2000 to 2024. Intentional sampling techniques were employed to guarantee the inclusion of female athletes across a diverse array of sports disciplines, including but not limited to soccer, ice hockey, running, and competitive dance. This approach aimed to provide a holistic view of biomechanical factors across different athletic activities. Data extraction systematically collected information from the selected studies, including study characteristics, participant profiles, methodology, and relevant outcomes pertaining to biomechanical factors linked to FAI in female athletes. A comprehensive literature review was performed, and articles that met the inclusion criteria were identified. The Downs and Black tool was subsequently used to evaluate the methodological quality of each study, recognizing the importance of considering factors such as reporting clarity, external validity, bias, confounding, and statistical power. Common themes were synthesized, and it was found that specific biomechanical factors, such as hip joint mechanics during dynamic movements and abnormal loading patterns, played significant roles in the development and progression of FAI in female athletes.