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People with knee Osteoarthritis (OA) often develop negative psychosocial beliefs like pain catastrophizing and fear avoidance that can interfere with engagement in physical activity and adherence to exercise. This can lead to further pain and disability since exercise and physical activity are the first line treatment for knee OA. Therefore, there is a need for interventions that address negative psychosocial beliefs related to exercise and low adherence along with addressing physical impairments of knee OA. This dissertation examined the safety, feasibility, and acceptability of a novel telehealth mindful exercise intervention for people with knee OA. The mindful exercise intervention trains individuals to incorporate concepts of mindfulness into strengthening exercises recommended for knee OA. The intervention was delivered via telehealth to facilitate access. Study 1 used a decentralized randomized controlled trial (RCT) of mindful exercise (n=21) vs. exercise alone (n=19) in people with knee OA. Mindful exercise was safe with 0 adverse events (vs. 4 in exercise group) and lower use of oral analgesics. The design was feasible for recruitment and retention, but adherence was suboptimal (53% in mindful exercise group) and the cohort was not racially diverse. Participants in the mindful exercise group reported larger clinically meaningful improvements in pain intensity, interference, catastrophizing, quality of life, and global assessment of knee OA compared to the exercise group. Study 2 was to qualitatively determine the acceptability of the mindful exercise intervention. Participants in the mindful exercise group of the RCT (n = 13 of 21) participated in individual interviews that were informed by the Theoretical Framework of Acceptability. Participants valued the content (exercise and mindfulness) and format (telehealth, group) of the intervention. Areas for further refinement included exercise selection and equipment, additional support and education on mindfulness, and greater flexibility with timing and nature of intervention sessions. Study 3 investigated the association between telehealth satisfaction and ehealth literacy in both groups. Participants in this cohort had high ehealth literacy (mean = 31.3 on a 8–40 scale) at baseline and high satisfaction with telehealth (mean = 5.6 on a 1–7 scale) at the end of the intervention. There was no association between ehealth literacy and telehealth satisfaction (R2=0.01, p=0.61). In conclusion, telehealth mindful exercise could be a safe and feasible intervention for people with knee OA. However, further refinement to improve adherence and acceptability are needed prior to efficacy studies.

Purpose: The purpose of this study was to investigate the origins of differing tonic muscle activity in three populations with known differences in neuromuscular processing. Methods: We manipulated healthy young adults, healthy older adults and individuals with Parkinson's disease (PD), both on and off dopamine therapy medication, with a novel technique related to muscle after contraction (MAC). We also investigated the transfer of tonic activity to the contralateral (unmanipulated) limbs to determine whether tonic activity is modulated through inhibitory and facilitatory interneuronal processes at a peripheral, spinal, or supraspinal level. In independent trials, we examined MAC in both proximal (medial deltoid) and distal (tibialis anterior) postural musculature by having subjects perform a voluntary, isometric contraction of the upper arm or ankle, respectively. Using surface electromyography (sEMG) to record the activity of the motor units before, during and after contraction, we were able to examine the differences in motor unit recruitment across the different populations from both an amplitude and frequency analyses. To test the transfer of tonic muscle activity to contralateral limbs, we manipulated conscious attention by having individuals focus on the unmanipulated limb during the post-contraction phase. Results: Our result shows significant changes in the prevalence of MAC with age and disease state. Moreover, some subjects with PDs showed variable evidence of tonic motor irradiation across the body, which was not seen in healthy individuals. Subjects with PD also showed unintended involuntary movement in the contralateral limb when treating the affected side, but were able to inhibit this behavior when explicit attention was paid to the unmanipulated side. Healthy young adult subjects consistently showed a MAC in their medial deltoids. Healthy older adults returned to baseline muscle activity following a contraction. During the attention conditions, there was increased muscle activity in the contralateral limb across subject groups. Conclusions: The findings from this series of studies may deepen our understanding of how aging and neural disease affect the unconscious tonic neuromuscular processes that serve as the foundation for all motor activity. This may help shape future rehabilitation techniques, particularly in decreasing fall risk, for the PD population as well as healthy agers. / Bioengineering

Running injuries have been linked to poor lower extremity dynamic alignment, increased whole body and joint loading, and insufficient modulation of stiffness throughout stance phase. Upper body muscle activity and movement have a relationship to lower body dynamics; however, the literature has largely neglected their role during running. To date, biomechanical gait analysis has primarily focused on lower extremity mechanics and muscle activation patterns with no studies investigating the role of functional muscle synergies on stability and loading during running. Therefore, the primary objective of this project is to determine the role of the Back Functional Line (BFL), via measure of latissimus dorsi (LD), gluteus maximus (GM), and vastus lateralis (VL) muscle activity, during running and to determine their influence on lower extremity kinematics and kinematic predictors of loading that are linked to running-related injuries (RRI). We used conditions of arm swing constraint to manipulate the action of the LD and investigate the response in GM and VL muscles. Our main variables of interest include: 1) BFL muscle activity, specifically mean and peak amplitude, onset, and co-activation of the LD and GM 2) frontal plane lower extremity kinematics, and 3) kinematic predictors of kinetics, specifically foot inclination angle at initial contact and vertical COM displacement. Twenty healthy recreational runners (10 M; 10 F) participated in this study. Male runners tended to be slighter older with a higher weekly running mileage and longer running history. All participants were between the ages of 18 and 55 years old and consistently ran at least once per week. Participants ran under three arm conditions - free arm swing, unilateral arm swing constraint, and bilateral arm swing constraint. During the running trials, surface EMG and lower extremity kinematics were collected over the gait cycle. We operationally defined the primary BFL as the muscle synergy composed of the non-dominant upper extremity (i.e., constrained side during unilateral condition) LD muscle, the dominant GM muscle, and the dominant VL muscle. The secondary BFL was defined as the dominant upper extremity (i.e., unconstrained during unilateral condition) LD muscle, the non-dominant GM muscle, and the non-dominant VL muscle. Primary and secondary BFL muscle synergy activity were analyzed during two specific phases of gait - the pre-activation (PA) phase and the loading response (LR) phase. In support of the hypothesis, the primary BFL LD mean amplitude decreased during both the PA and LR phases of gait. GM and VL muscle mean amplitude demonstrated a varied response. During the PA phase, both the GM and VL muscles increased during the unilateral condition and decreased during the bilateral condition. During LR phase, GM and VL muscles increased during both arm swing constraint conditions. The highest increase in amplitude was seen during the unilateral condition. Peak amplitudes for each muscle did not change dramatically across conditions for either the PA or LR phases of gait. Secondary BFL LD and GM mean and peak amplitude increased during both the PA and LR phases of gait, with changes during the LR phase reaching significance for both muscles. Secondary BFL VL also increased in mean and peak amplitude during the bilateral constraint condition. GM and VL mean and peak muscle amplitude were significantly correlated during the LR phase, but not for the PA phase. This indicates that the lower extremity muscles of the BFL (GM and VL) may not be preparing for impact similarly but are adjusting muscle activity in a similar fashion as the lower limb is loaded. The increase in muscle amplitude for secondary BFL muscles, particularly during the LR phase of gait, may have resulted from a difference between lower limb strength or lower extremity single leg stability. Onset of muscle activity during loading response did not significantly differ across conditions for the LD, GM, or VL muscles, however, analysis of co-activation demonstrated that LD and GM were in-phase throughout the gait cycle. This suggests that this portion of the BFL may be acting together to stabilize the lumbopelvic-hip complex (LPHC) during running. LD and GM appeared to be co-activated throughout the gait cycle regardless of arm swing variation. Instability, either from asymmetrical movement patterns or poor single leg stability may contribute to the activation of the BFL muscle synergy. GM increased during the unilateral arm swing constraint during both phase and for both BFL synergies, indicating that asymmetrical movement patterns may induce a potential instability or an unstable state requiring the need for greater stability around the LPHC. Knee frontal plane kinematics changed significantly across conditions. Knee abduction angle showed the greatest increase during the unilateral arm swing constraint condition suggesting that asymmetrical movement patterns effect lower extremity mechanics more so than symmetrical patterns (i.e., bilateral arm swing restriction or free arm swing). Hip adduction and contralateral pelvic drop angles did not differ significantly across conditions. Our study did not find a significant relationship between BFL muscle activity and knee abduction angles. Participants demonstrated larger knee abduction angles on their non-dominant limb at midstance. The corresponding (secondary) BFL LD and GM demonstrated a significant increase during the LR phase. This may indicate that BFL muscle activity is engaged when the need for lower limb stability is greater, either due to poor single leg dynamic control or abnormal frontal plane mechanics. Kinematic predictors of joint and whole-body loading differed across conditions. Vertical COM displacement was significantly decreased during the bilateral arm swing constraint condition. Foot inclination angle at initial contact did not significantly change with arm swing constraint. Differences were found between right and left lower extremity foot strikes (i.e., foot inclination angle) across all conditions; the non-dominant limb demonstrated greater plantarflexion during initial contact. Knee flexion angle at initial contact and peak knee flexion during stance did not demonstrate a significant change. Muscle activity was not significantly correlated to kinematic predictors. Spatiotemporal measures altered with arm swing suppression. Stride length decreased and step rate increased significantly. Taken together, these results suggest that runners alter spatiotemporal measures more so than sagittal plane kinematics when adjusting to arm swing suppression. The role of the BFL muscle synergy during running remains unclear. Asymmetrical movement patterns and arm swing restriction appear to influence BFL muscle activity and lower extremity kinematics. Single leg stability, particularly during the LR phase, may alter BFL muscle activity due to the need for increased stabilization of the loaded limb and the LPHC. Future research is needed to determine how these variables impact BFL muscle activation and whether injured runners respond differently to arm swing constraint during running. / Physical Therapy

Movement problems related to Parkinson’s disease (PD) have been shown to have a profound effect on functional independence and reported quality of life. Within the constellation of movement signs of PD (tremor, muscle rigidity, bradykinesia/hypokinesia, and postural instability), impaired arm swing is often the earliest-recognized symptom. It is also a strong independent predictor of greater fall risk and morbidity/mortality risk. Early treatment for movement problems such as impaired arm swing is associated with the greatest improvement in these impairments. However, movement problems often coincide with impaired processing of sensory information, leaving many people with PD with inadequate awareness of their posture and limb position. Thus, PD-related gait deficits are difficult for people to correct by themselves. External cueing techniques (such as visual cues in the environment or auditory cues for pacing and rhythm) have shown promise in improving parameters such as gait speed, s / Kinesiology