Engaging undergraduate students in an online science course: the relationship between instructor prompt and student engagement in synchronous class sessions

The number of online courses in higher education is on the rise; however, empirical evidence elucidating best practices for synchronous online instruction is needed to implement these courses. The purpose of this dissertation was to perform a mixed-method investigation into the relationships between instructor prompt and student engagement in 5 areas based on the 7 Principles of Good Practices in Undergraduate Education using recorded chat, video, and audio transcripts of two recent fully online nutrition courses. A total of 25 previously recorded synchronous sessions including oral and textual chat interactions were transcribed. Every line of student interaction was determined to be either superficial or containing evidence of at least one instance of engagement. Every line of instructor interaction was concurrently coded for at least one of the following forms of prompt: social, organizational, intellectual. Inter-tester reliability of coded interactions was determined to be excellent (Cohen\u27s kappa = 0.91) on a 5% sample of the entire dataset before comprehensive analysis continued. In total, 172,380 words were exchanged through 13,394 oral and text interactions across all class sessions. With 54% of student interactions deemed superficial the remainder produced a total of 8,906 student engagements. There were 4,125 instructor prompts composed of 48% intellectual, 30% organizational, and 22% social cues. Pearson correlations were performed to investigate relationships between prompt and engagement across class sessions. Intellectual prompts were the best predictor of faculty interactions, active and collaborative learning, and academic challenge (r=0.77, r=0.78, r=0.54 respectively); organizational prompts were the best predictor of enriching academic experiences (r=0.72); and social prompts were the best predictor of supportive campus environments (r=0.79) with all of these being significant (p\u3c0.01). No category of engagement was significantly correlated to class performance. Online synchronous class sessions can promote high levels of student engagement. A variety of instructor prompts must be used in order to promote student engagement across a number of different categories. Finally, care should be taken in order to craft and facilitate learning activities in synchronous online class sessions in order to achieve desired learning outcomes

Whole Body Vibration Training is Osteogenic at the Spine in College-Age Men and Women

Osteoporosis is a chronic skeletal disease characterized by low bone mass which is currently challenging the American health care system. Maximizing peak bone mass early in life is a cost-effective method for preventing osteoporosis. Whole body vibration (WBV) is a novel exercise method with the potential to increase bone mass, therefore optimizing peak bone and decreasing the risk for osteoporotic fracture. The aim of this investigation was to evaluate changes in bone mineral density at the hip, spine, and whole body in college-age men and women who underwent a WBV training protocol. Active men (n=6) and women (n=4), ages 18-22 participated in the WBV training; while an additional 14 volunteers (1 male, 13 female) served as controls. All participants completed baseline and follow-up questionnaires to assess health history, physical activity, dietary intake, and menstrual history. The WBV training program, using a Vibraflex 550, incorporated squats, stiff-leg dead lifts, stationary lunges, push-up holds, bent-over rows, and jumps performed on the platform, and occurred 3 times a week, for 12 weeks. Dual energy x-ray absorptiometry (Hologic Explorer, Waltham, MA, USA) was used to assess bone mineral density (BMD, g/cm2). A two-tailed, t-test identified significantly different changes in BMD between the WBV and control groups at the lateral spine (average change of 0.022 vs. -0.015 g/cm2). The WBV group experienced a 2.7% and 1.0% increase in BMD in the lateral spine and posterior-anterior spine while the control group decreased 1.9% and 0.9%, respectively. Results indicate that 12 weeks of WBV training was osteogenic at the spine in college-age men and women

Effect of Training Mode on Post-Exercise Heart Rate Recovery of Trained Cyclists

The sympathetic nervous system dominates the regulation of body functions during exercise. Therefore after exercise, the sympathetic nervous system withdraws and the parasympathetic nervous system helps the body return to a resting state. In the examination of this relationship, the purpose of this study was to compare recovery heart rates (HR) of anaerobically versus aerobically trained cyclists. With all values given as means ± SD, anaerobically trained track cyclists (n=10, age=25.9 ± 6.0 yrs, body mass=82.7 ± 7.1 kg, body fat=10.0 ± 6.3%) and aerobically trained road cyclists (n=15, age=39.9 ± 8.5 yrs, body mass=75.3 ± 9.9 kg, body fat=13.1 ± 4.5%) underwent a maximal oxygen uptake test. Heart rate recovery was examined on a relative basis using heart rate reserve as well as the absolute difference between maximum HR and each of two recovery HRs. The post-exercise change in HR at minute one for the track cyclists and road cyclists respectively were 22 ± 8 bpm and 25 ± 12 bpm. At minute two, the mean drop for track cyclists was significantly (p\u3c0.05) greater than the road cyclists (52 ± 15 bpm and 64 ± 11 bpm). Training mode showed statistically significant effects on the speed of heart rate recovery in trained cyclists. Greater variability in recovery heart rate at minute two versus minute one suggests that the heart rate should be monitored longer than one minute of recovery for a better analysis of post-exercise autonomic shif

Norms for an Isometric Muscle Endurance Test

Musculoskeletal performance assessment is critical in the analysis of physical training programs in order to prioritize goals for decreasing injury risk and focusing performance goals. Abdominal endurance as part of this analysis is often assessed with techniques that have validity that has been debated in literature. The purpose of this study was to develop normative sex- and athlete-specific percentiles for a trunk stabilization and muscular endurance by using a prone forearm plank test in college-aged students. A second purpose of this study was to investigate the effect of habitual physical activity and the reason for test termination. There were 471 participants (means SE; males: n = 194, age 20.4 0.2 years, body height 179.4 0.5 cm, body mass 81.1 1.2 kg; females: n = 277, age 20.2 0.2 years, body height 165.7 0.4 cm, body mass 63.9 0.7 kg) who performed this test to volitional or technique failure. Males produced significantly higher test durations than females (means SD; 124 72 seconds vs. 83 63 seconds) and athletes produced significantly longer test durations than non-athletes (123 69 s vs. 83 63 s) but no interaction effects were seen in the variables of sex and athletic status. The activity level was found to have a threshold of influence (\u3e3 times/week) on abdominal endurance that is dose-specific where greater than 5 times/week showed the greatest influence. The fatigue of the abdominals was the termination reason producing the lowest test duration and there was no sex effect on reason for test termination. These normative percentiles for abdominal endurance suggest that the abdominal plank test can now be used as an alternative to other abdominal assessments in college students, but further investigation is warranted prior to confirmation and generalization to other populations

Volume estimations for combined free-weight and rubber-band resistance exercise

Volume, or the total work performed during resistance training is one of the vital variables of resistance exercise programming. The most common definition in use by practitioners is sets x reps x external weight. While appropriate for linear loading incurred through free-weight resistance exercise, this inadequately addresses the nonlinear loading incurred with rubber resistance, a relatively new loading technique. The purpose of this investigation was to derive a theoretical model to describe a method of volume calculation for rubber band plus free-weight exercise. Men (n=51; age 19.5±1.6 years; body height 1.76±0.07 meters; body weight 77.3±11.3 kilograms) and women participants (n=66; age 18.9±1.1 years; body height 1.65±0.07 meters; body weight 62.8±9.1 kilograms) were measured for band lengths incurred at: squat with knee extended position, squat with flexed position, and change in band length was then calculated. Significant gender differences were seen for band length change as a percentage of body height (p<0.5) during the squat, which mandated separate volume equations (females=33.8%; males=35.3% of body height). Equations were determined for total external volume estimation in kgm=[0.338(m+2c2+(ln(h)-0.383)2c1)]/g and kgm=[0.352(m+2c2+(ln(h)-0.382)2c1)]/g for females and males, respectively, where m is the total external resistance, c2 and c1 are constants derived from rubber-band loading parameters, h is the body height of the participant, and g is gravitational acceleration. This work provides practitioners and researchers with a simple theoretical method for work estimation using participant’s body height to estimate displacement values during the squat exercise

Velocity at maximal oxygen uptake best predicts 3 km race time in collegiate distance runners

Purpose: There is a lack of scientific investigation into the predictors of 3 km race performance in collegiate distance runners. The purpose of this investigation was to determine what physiological variables best predict 3 km race time in a group of collegiate distance runners. Methods: Twenty-one endurance trained runners (11 men, 10 women) volunteered for this investigation. Running economy (RE) and maximal oxygen uptake (VO2max) testing were conducted within 9 ± 6 days of the race in a single session. All participants ran in a 3 km race at an NCAA sanctioned track meet. Pearson’s product moment correlations were performed between 3 km race time and velocity at VO2max (vVO2max), relative VO2max, RE at 9.7, 11.3, 12.9, and 14.5 km•hr-1 and percent of VO2max. A stepwise multiple regression was performed with 3 km race time as the dependent variable and independent variables of vVO2max, VO2max, RE9.7, RE11.3, RE12.9, RE14.5. Results: The results revealed that vVO2max was the best predictor of 3 km race performance in a heterogeneous group of collegiate distance runners (R2=0.90). For the men, vVO2max remained the best predictor of 3 km race performance (R2=0.49). For the women, the best predictors of 3 km performance were vVO2max and VO2max (R2=0.97). Conclusions: Distance coaches should consider emphasizing vVO2max as a primary factor in training to improve 3 km race performance and conversely, the pace achieved in a 3-km race is a good predictor of vVO2max

Contractile function of single muscle fibers from chronically resistance trained humans

Resistance training is widely prescribed for rehabilitation of injuries and as a method to improve athletic performance. It is accepted that resistance training increases the maximal force production of whole muscle and it has been suggested that the velocity of shortening can increase as well. However, little is known about the effects of resistance training at the cellular level. Therefore, we investigated morphology, force production, velocity, and force-velocity-power relationships of single chemically skinned muscle fibers from chronically resistance trained humans, including cross sectional area (CSA), peak Ca²⁺ -activated force production (P₀), specific tension (P₀/CSA), unloaded shortening velocity (V₀), and isotonic contractions. The untrained group (NT) group consisted of sedentary males (n=6, age =27 ± 2 yrs) while the chronically trained group (CHRT) group consisted of males with 7.7 ± 0.4 yrs resistance training experience (n=6, 22 ± 1 yrs). Maximum voluntary isometric and isokinetic knee extensor strength were measured along with 6 repetition maximum (6RM) free weight bench press and leg press. Muscle biopsies were obtained from the vastus lateralis. Chemically skinned single muscle fibers were mounted between a force transducer and servo-controlled motor and subjected to slack tests to determine peak Ca²⁺ -activated force (P₀) and unloaded shortening velocity (V₀). Isotonic load clamps were used to determine the force-velocity-power relationship. All fiber experiments were performed at 15°C. Fiber myosin heavy chain (MHC) content was determined by gel electrophoresis. The CHRT group was 119% and 81% stronger for 6RM leg press and bench press respectively. Peak isometric torque was 28% greater for the CHRT subjects and was significantly higher at all isokinetic speeds tested. No differences were seen in strength or isokinetic power between groups after normalization for lean body mass. CHRT fibers (n=213) expressing type I, IIa, and I₀a/IIx MHC were significantly greater in CSA (+41%, +51%, and +33%, respectively) and produced significantly greater P₀ (+37%, +48%, and +34%, respectively) than NT fibers (n=236). However, P₀/CSA was not different between CHRT and NT groups. Fibers expressing type IIa/IIx fibers produced greater P₀/CSA than IIa which produced greater P₀/CSA than type I. The P₀/CSA relationship between fibers within groups was type IIa/IIx>IIa>I and was significant for both groups. Fiber V₀ was not different between groups. Absolute power was significantly greater in the CHRT for all fiber types whereas power normalized for fiber volume was not different between groups. This resulted in a significantly greater force at peak power for all but type IIa/IIx fibers and trends for greater velocity at peak power. Single-cell contractile function in terms of V₀ and P₀/CSA, measured under standardized conditions, appears to be unaltered as a result of long term CHRT in young adult males. Group differences in absolute P₀ can be attributed solely to the greater CSA of the CHRT fibers. Long-term CHRT is not associated with a difference in fiber V₀. Therefore, the greater power was due entirely to the greater force. These data suggest that differences in whole muscle strength and power between NT and CHRT groups are primarily due to differences in fiber CSA rather than differences in cross-bridge mechanisms of contraction. Supported by National Institute of Health grant R3AR46392A

Whole Body Vibration Training is Osteogenic at the Spine in College-Age Men and Women

Osteoporosis is a chronic skeletal disease characterized by low bone mass which is currently challenging the American health care system. Maximizing peak bone mass early in life is a cost-effective method for preventing osteoporosis. Whole body vibration (WBV) is a novel exercise method with the potential to increase bone mass, therefore optimizing peak bone and decreasing the risk for osteoporotic fracture. The aim of this investigation was to evaluate changes in bone mineral density at the hip, spine, and whole body in college-age men and women who underwent a WBV training protocol. Active men (n=6) and women (n=4), ages 18–22 participated in the WBV training; while an additional 14 volunteers (1 male, 13 female) served as controls. All participants completed baseline and follow-up questionnaires to assess health history, physical activity, dietary intake, and menstrual history. The WBV training program, using a Vibraflex 550, incorporated squats, stiff-leg dead lifts, stationary lunges, push-up holds, bent-over rows, and jumps performed on the platform, and occurred 3 times a week, for 12 weeks. Dual energy x-ray absorptiometry (Hologic Explorer, Waltham, MA, USA) was used to assess bone mineral density (BMD, g/cm(2)). A two-tailed, t-test identified significantly different changes in BMD between the WBV and control groups at the lateral spine (average change of 0.022 vs. −0.015 g/cm(2)). The WBV group experienced a 2.7% and 1.0% increase in BMD in the lateral spine and posterior-anterior spine while the control group decreased 1.9% and 0.9%, respectively. Results indicate that 12 weeks of WBV training was osteogenic at the spine in college-age men and women