Exercise therapy in Type 2 diabetes

Structured exercise is considered an important cornerstone to achieve good glycemic control and improve cardiovascular risk profile in Type 2 diabetes. Current clinical guidelines acknowledge the therapeutic strength of exercise intervention. This paper reviews the wide pathophysiological problems associated with Type 2 diabetes and discusses the benefits of exercise therapy on phenotype characteristics, glycemic control and cardiovascular risk profile in Type 2 diabetes patients. Based on the currently available literature, it is concluded that Type 2 diabetes patients should be stimulated to participate in specifically designed exercise intervention programs. More attention should be paid to cardiovascular and musculoskeletal deconditioning as well as motivational factors to improve long-term treatment adherence and clinical efficacy. More clinical research is warranted to establish the efficacy of exercise intervention in a more differentiated approach for Type 2 diabetes subpopulations within different stages of the disease and various levels of co-morbidity

CARDIOVASCULAR RESPONSES TO A THREE WEEK LOW-VOLUME HIGH-INTENSITY CYCLING PROTOCOL

Bovorn Sirikul. Southeastern Louisiana University, Hammond, LA. BACKGROUND: High-intensity interval training (HIIT) has shown promise as an effective replacement for traditional longer-duration moderate exercise due to the considerably lower time commitment, but additional evidence is needed to determine how little exercise is enough to elicit improvements in cardiorespiratory fitness. It was hypothesized that significant increases in VO2max would be observed after ten sessions of the 2x3 protocol. Thus, the purpose of this study was to examine the cardiorespiratory responses using this protocol in healthy, sedentary individuals. METHODS: Fourteen participants completed baseline oxygen consumption (VO2max) testing using a cycle ergometer. Heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP), VO2, respiratory exchange ratio (RER), and rate of perceived exertion (RPE) were measured. Pulse pressure and rate pressure product (RPP) were calculated from the observed values. Exercise intervention trials began 48 hours after the completion of baseline testing. The protocol was three weeks long consisting of three sessions lasting ~14 minutes each week. Each session consisted of a warm-up, followed by two 3-min sub-maximal high-intensity cycling intervals at 85-90% of VO2max at rates of 50-100 rpm with two minutes of low-intensity (50-60% VO2max) recovery between and a cool-down after the second interval. RESULTS: No significant changes were observed for maximal graded exercise test HR, peak RER, maximal DBP, or time to exhaustion. However, VO2peak increased from 31.79 ± 1.14 ml*kg-1*min-1 pre-intervention, to 35.89 ± 1.81 ml*kg-1*min-1 post-intervention, resulting in a significant improvement (p=0.012). Significant increases were also observed in maximal SBP (158 ± 5.5 mmHg to 174.43 ± 9.28 mmHg; p=0.030), as well as RPP at HR max (288.20 ± 11.65 bpm to 314.48 ± 16.38 bpm; p=0.043). CONCLUSIONS: The employed low-volume high-intensity protocol period did elicit a significant improvement in VO2peak as has been shown in a number of previous HIIT studies. Since the 14-minute protocol was well tolerated by participants, the findings of this study demonstrated the potential of a low-volume high-intensity cycling protocol to increase exercise adherence due to its short duration and sub-maximal nature. This project was partially supported by the Kenelly Family Endowed Professorship

THE INFLUENCE OF SURFACES ON ACCELERATION AND DECELERATION CAPACITY AND RATING OF PERCEIVED EXERTION

Megan A. Gordon, Brandi E. Decoux, FACSM, Bovorn Sirikul, FACSM. Southeastern Louisiana University, Hammond, LA. BACKGROUND: Soccer is a high intensity sport requiring frequent changes in speed and direction. Though the sport is traditionally played on natural grass (NG), it has become more prominent in recent years for artificial turf (AT) to be considered as an acceptable alternative. Consequently, there has been an increase in studies focused on the impact of different playing surfaces on injury rates and player perception. Additional research, however, is needed to better understand how these surfaces influence the mechanical demands observed during performance as well as the perceived physiological demands. Thus, the purpose of this study is to investigate acceleration and deceleration profiles and rating of perceived exertion (RPE) among NCAA Division I women’s soccer players on NG vs AT. METHODS: Participants between the ages of 18 to 23 years will be recruited from a Division I women’s soccer team. Data will be collected across a competitive season using TITAN 1+ GPS wearable sensors and the TITAN Athlete App (Integrated bionics, Houston, TX, USA). Each participant will wear a GPS sensor within a fitted undergarment vest under their jersey during each match, and afterwards, each will report their RPE in the app using their personal smartphone. At each match, the type of playing surface (i.e., NG or AT) will be documented and wet bulb globe temperature (WBGT) will be recorded at 15 minute intervals throughout each 90-minute event to account for the effect of temperature, humidity, and solar radiation on the players. Data collected with the GPS sensors and the app will automatically be compiled in the TITAN Session Explorer software from which the accelerations, decelerations, and RPE collected for each game will be exported for analysis. Data on NG vs AT will be analyzed using repeated measures t-tests. Pearson correlation tests will also be conducted to measure the strength of the relationship between RPE and accelerations, decelerations, and WBGT. ANTICIPATED RESULTS: It is hypothesized that there will be a greater number of accelerations and decelerations on AT than NG, and RPE will be higher on AT than NG. In addition, it is also hypothesized that accelerations, decelerations, and WBGT will be correlated to RPE

Exercise over-stress and maximal muscle oxidative metabolism: a (31)P magnetic resonance spectroscopy case report

Objective: (31)P magnetic resonance spectroscopy (MRS) was used to document long lasting losses in muscle oxidative capacity after bouts of intense endurance exercise. Methods: The subject was a 34 year old highly fit female cyclist (VO(2)MAX = 53.3 ml/kg/min). Over a five month period, she participated in three separate intense bouts of acute unaccustomed exercise. (31)P MRS measurements were performed seven weeks after the first bout and every two weeks for 14 more weeks. In all cases, (31)P MRS measurements followed three days after each bout. Results: The subject showed a decreased ability to generate ATP from oxidative phosphorylation and an increased reliance on anaerobic ATP production during the 70% and 100% maximal voluntary contractions after the exercise bouts. Increased rates of fatigue and increased indicators of exercise difficulty also accompanied these reductions in muscle oxidative capacity. Increased oxidative and anaerobic ATP production were needed to maintain the work level during a submaximal 45% maximal voluntary contraction exercise. Conclusions: Acute increases in intensity accompanied by a change in exercise mode can influence the ability of muscle to generate ATP. The muscles were less economical and required more ATP to generate force during the submaximal exercises. During the maximal exercises, the muscle's mitochondria showed a reduced oxidative capacity. However, these reductions in oxidative capacity at the muscle level were not associated with changes in whole body maximal oxygen uptake. Finally, these reductions in muscular oxidative capacity were accompanied by increased rates of anaerobic ATP production, fatigue, and indicators of exercise difficulty

INFLUENCE OF NATURAL GRASS AND ARTIFICIAL TURF SURFACES ON ATHLETE PERFORMANCE AND PERCEIVED PERFORMANCE SATISFACTION

Hannah Reck1, Brandi Decoux1, Samantha Carson1, Daniel B. Hollander1, Megan Gordon1, Bovorn Sirikul1, Christopher Wilburn2, Wendi Weimar2. 1Southeastern Louisiana University, Hammond, LA. 2Auburn University, Auburn, AL. BACKGROUND: Examination of athlete performance and perceptions across different playing surfaces has provided useful information to better understand athlete preferences, tactical alterations, and focus areas for industry/material science developers. However, much of the previous research on natural grass (NG) and artificial turf (AT) surfaces has been limited in scope to comparisons of only performance measures or only perceptual ratings. Additionally, fewer studies have assessed both performance and perception across multiple AT surfaces and NG within the same project. Thus, the purpose of this study was to investigate the influence of NG and different AT playing surfaces on athlete performance and perceived performance satisfaction. METHODS: Seventeen male participants (age: 23.1 ± 2.9 years; height: 1.81 ± 0.06 m; mass: 77.8 ± 9.9 kg) completed three 20-yard sprint trials and three change of direction (CoD) trials (i.e., 5-10-5 agility) on four playing surfaces-one NG surface and three AT surfaces with varying structural components. After completion of all performance tests, each participant then responded to a visual analogue scale (VAS) questionnaire for each surface regarding their satisfaction with the surface’s grip/traction and softness/compliance as well as their ability to change direction and accelerate. Friedman tests were conducted to compare sprint time, CoD time, CoD deficit, and the VAS scores across all surfaces. RESULTS: There were statistically significant differences detected for CoD deficit (χ2(3)= 9.071, p= 0.028), acceleration VAS score (χ2(3)= 10.089, p= 0.018), and softness/compliance VAS score (χ2(3)= 10.804, p= 0.013). Post hoc Wilcoxon signed-rank tests with a Bonferroni correction (a=.0125) revealed that CoD deficit on the third AT surface was larger than on NG (p= .008), the third AT was ranked higher for acceleration VAS score than the second AT (p=.003), and the third AT was ranked lower than NG for softness/compliance VAS score (p=.002). CONCLUSION: Interestingly, the participants in this study perceived the third AT to be a harder surface that they could accelerate better on, and yet CoD deficit, a measure that is improved by enhanced acceleration ability, was compromised on this surface compared to NG. These findings suggest that perceptions of the performance-related characteristics of AT and actual performance are not always congruent. KEYWORDS: Perception, Performance, Artificial turf, Natural Gras

ASSESSMENT OF GAIT HARMONY IN PRIMARY SCHOOL-AGED CHILDREN USING A GOLDEN RATIO-CENTERED APPROACH

Brandi E. Decoux1, Christopher M. Wilburn2, Wendi H. Weimar2, Portia T. Williams3, Megan Gordon1, Bovorn Sirikul1, Sarah Price4. 1Southeastern Louisiana University, Hammond, LA. 2Auburn University, Auburn, AL. 3North Carolina Agricultural and Technical State University, Greensboro, NC. 4Florida Agricultural and Mechanical University, Tallahassee, FL. BACKGROUND: The mature walking gait of healthy adults is well known to exhibit proper timing of gait events, and more recent research has found that a self-similar harmonic structure is also present wherein the temporal proportions of repetitive gait phases coincide with the golden ratio, an irrational number also known as phi (φ = 1.618034⋯). However, this phi-proportionality feature was not observed in the gait of individuals with decreased motor ability or altered anthropometric proportions. The purpose of this study was to assess whether the gait of primary school-aged children, a sub-set of humans undergoing motor ability development and physical growth, demonstrates this harmonic phi-proportionality feature. METHODS: Spatiotemporal gait parameters of 21 primary school-aged children between grades 1 and 5 (15 females, 6 males; height 1.48 ± 0.23 m; mass 40.9 ± 18.3 kg) were analyzed using a 2.55 m pressure-sensing mat where the participants walked across barefoot at a self-selected pace. Three one-sample t-tests (α =.05) were carried out to separately compare the gait cycle to stance ratio (Ratio 1: 1.615 ± 0.034), stance to swing ratio (Ratio 2: 1.640 ± 0.090), and swing to total double support ratio (Ratio 3: 1.612 ± 0.195) to the golden ratio. A within-subjects repeated measures ANOVA (α =.05) was also conducted to assess for symmetry amongst the three ratios. RESULTS: No statistically significant difference was found between the golden ratio and Ratio 1 (t(20)= -.361, p = .722), Ratio 2 (t(20)= 1.166, p = .257), or Ratio 3 (t(20)= -.139, p = .891). In addition, no statistically significant differences were found between any of the phase ratios, F(2,19)=1.526, p= .243. CONCLUSIONS: Previous research has found that artificially altering the body segment proportions of healthy adults affects the harmonic organization of gait phases. However, our findings lend support to a more recent longitudinal study which discovered that the gait phase ratios of children throughout early childhood converged towards the golden ratio as they gained more locomotor experience and transitioned from supported to independent walking. Thus, this project provides further evidence suggesting that the typical phi-proportionality of anthropometric parameters has less of an influence on gait harmony than other factors like balance, walking speed, and pathophysiology