Health, Nutrition & Exercise Science Doctoral Work

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Browsing Health, Nutrition & Exercise Science Doctoral Work by browse.metadata.program "Health, Nutrition, and Exercise Sciences"

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    Appraising Anterior Cruciate Ligament Injury Risk: Single-Legged Jump-Landing Dynamic Postural Stability
    (North Dakota State University, 2022) Bond, Colin
    Appraising anterior cruciate ligament (ACL) injury risk is of great interest to the orthopedic and sports medicine professional. Due to the high prevalence of non-contact ACL injuries, professionals have sought to identify intrinsic and modifiable neuromuscular and biomechanical risk factors to aid in the design of injury risk screens that have the discriminatory capacity to stratify ACL injury risk and the efficiency to be implemented at-scale. Prospective studies have revealed that poor dynamic postural stability (DPS), quantified as time to stabilization (TTS), following a backwards single-legged jump-landing (BSLJL) and poor hip external rotation and abduction strength relative to body weight, quantified using a handheld dynamometer, are two risk factors for ACL injury. The purposes of this study were to assess the effects of repeated BSLJL on within-session motor learning as quantified by DPS, evaluate the reliability of DPS, and determine the relation between DPS, hip strength, and fatigue. Twenty-seven recreationally active college-aged adults (24.0 ± 2.8 y, 1.73 ± 0.08 m, 75. ± 14.0 kg) were enrolled in this semi-randomized, cross-over study. During visit one, subjects completed 10 BSLJL trials per leg without familiarization and had their hip external rotation and abduction strength measured. During visits two through four, subjects complete two fatigue sessions and one control session in a randomized order. During these sessions, subjects completed two sets of three BSLJL trials per leg separate by either a seated rest in a chair (control) or a short-term functional fatigue protocol (fatigue). DPS was quantified as TTS and the dynamic postural stability index (DPSI). To appropriately familiarize a subject to the BSLJL, results suggest that a minimum of six familiarization trials per leg are required to sufficiently reduce the motor learning effect. Results also indicate that TTS reliability is poor after 10 trials per leg whereas DPSI reliability is good after just two trials per leg and excellent after just six trials per leg. Finally, results indicate that following completion of a fatigue protocol, there are decrements in TTS, but not in DPSI. Further, greater hip abduction strength is associated with better DPSI when rested and fatigued, but not TTS.
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    The Effects of Greater Dietary Protein Spread and Quality on Muscle Health in Healthy Adults
    (North Dakota State University, 2022) Johnson, Nathaniel
    Skeletal muscle is critically important, but is often overlooked, not getting the respect or attention the tissue demands. Muscle is responsible for locomotion and physical performance, uses large amount of energy preventing gains in fat mass, and acts as an amino acid reservoir during trauma. Nonetheless, as individuals age, they lose muscle and to a greater extent strength. Maintaining muscle mass and strength is paramount for preventing disability and mortality. There are many aspects of diet that affect muscle tissue, but dietary protein directly activates muscle protein synthesis, so is important to consider as part of a balanced diet. Research regarding dietary protein intake has focused on the amount of protein consumed, but the quality and distribution of dietary protein also determines the body’s anabolic response. Two different cross-sectional studies were completed to determine the associations between dietary protein intake and muscular performance. Dietary intake was measured using three-day food diaries. Isokinetic dynamometry determined lower-body strength and endurance. Handgrip strength measured upper-body strength. Dual x-ray absorptiometry evaluated lean body mass. Thirty-second chair stand and six-meter gait speed tests determined functional ability. Self-reported age and moderate-to-vigorous physical activty, assessed via accelerometry, were included in all models as covariates. Increased intake of higher quality proteins from animal sources was positively associated with lower-body strength (β ± S.E.; 65.874±19.855, p =0.001), lower-body endurance (549.944±232.478, p =0.020), and handgrip strength (0.349±0.171, p = 0.045) in the cross-sectional sample of 91 middle-aged men (n=41) and women (n=50) when controlling for relative energy intake and percent energy from the macronutrients. Using another sample of 192 women 18 to 79 years, achieving intakes of at 25 grams per meal was positively associated with lean mass (1.067±0.273 kg, p<0.001) and upper-body (3.274±0.737 kg, p<0.001) and lower-body strength (22.858±7.918 Nm, p=0.004) controlling for relative energy intake and percent of energy from protein. In a subgroup of this sample aged 61-79, animal-based protein intake was related to increased lower-body strength (14.834±7.287 Nm, p=0.049) and faster gait speed (-0.177±0.087 s, p=0.049). To benefit muscle and performance, people should strive to consume enough high-quality protein at each meal.
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    Systematic Intervention Component Analysis: Dose-Response for Therapeutic Ultrasound
    (North Dakota State University, 2022) Hamersky, Stephanie
    Therapeutic ultrasound has been well documented in the literature to affect human tissue. The four main parameters practitioners are able to influence are frequency, duty cycle, intensity, and treatment time. Alteration to one or more of these parameters will affect the total dose of acoustical energy delivered to the tissue resulting in a target tissue temperature increase or biophysical effect. The goal of this two-part study was to determine the appropriate energy dose of therapeutic ultrasounds needed to create a beneficial intervention when treating unhealthy human tissue. Prior to the investigation a non-systematic review was conducted to determine the dose-response and thermal outcome in laboratory studies. The first investigation used a systematic intervention component analysis (ICA) to determine the effectiveness and empirical relationship between the different parameters of an ultrasound intervention when treating unhealthy tissue. The second investigation included a four-part survey which addressed trends within parameter selection in the clinical setting and influences on clinical decision making. The first investigation findings indicated no one parameter had significant influence on the ultrasound treatment effectiveness. The second investigation findings indicated practitioners set a treatment goal of 2℃ and a mean predictive outcome between 1.85 and 2.56℃ regardless of the condition.
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    Using Electronic Handgrip Dynamometry to Determine Human Performance in Master's Aged Cyclists and Triathletes
    (North Dakota State University, 2022) Klawitter, Lukus
    Purpose: This dissertation study sought to examine the correlations of maximal handgrip strength (HGS), rate of HGS force development, and HGS fatigability on lean body mass, peak power, functional threshold power, and aerobic capacity in master’s aged cyclists and triathletes. Methods: A cross-sectional design was utilized and the analytic sample included n=31 master’s aged cyclists and triathletes (age: 49.1±10.4 years). Achievement motivation was self-reported with a Situational Motivation Scale Questionnaire. A stationary bicycle trainer and metabolic cart was used to evaluate peak power and aerobic capacity with standardized protocols. Whole body bioelectrical impedance measured lean body mass. An electronic handgrip dynamometer examined maximal HGS, rate of HGS force development, and HGS fatigability. Results: Maximal HGS was moderately correlated with peak power (r=0.46; p<0.01), lean body mass was moderately correlated with peak power (r=0.48; p<0.01) and negligibly correlated with aerobic capacity (r=0.37; p=0.04). Rate of HGS force development was also moderately correlated with peak power (r=0.36; p=0.04). Maximal HGS was moderately correlated with rate of HGS force development (r=0.63; p<0.01). Moreover, after ranking the measures, maximal HGS was moderately correlated with peak power (r=0.40; p=0.02) and lean body mass was moderately correlated with peak power (r=0.50; p<0.01). Conclusions: The findings from this dissertation study suggests that maximal HGS and rate of HGS force development share a signal with peak power in master’s aged cyclists and triathletes. Further, increased lean body mass is related to greater peak power. Maximal HGS and rate of HGS force development show promise for being utilized in a single protocol as a correlate for peak power when exhaustive testing is not possible, and maintaining lean mass is also advised for human performance in older endurance athletes.