The Effect of Acute Hyperglycemia on Muscular Strength, Power and Endurance

International Journal of Exercise Science 10(3): 390-396, 2017. The purpose of this study was to elucidate the impact of acute hyperglycemia on skeletal muscle strength, power, and endurance. Ten male collegiate athletes (age 21.5 ± 1.5 years, height 186 ± 2.03 cm, body mass 108.8 ± 7.6 kg) participated in 2 testing sessions, separated by 7 days and randomized for either high glucose (HG) or control (C) treatment conditions. HG consumed a high glucose drink (2 g glucose/kg body weight) while controls consumed an isocaloric nutrition bar (40% protein, 30% fat, and 30% carbohydrate). Blood glucose (BC) levels for HG and C were tested at 0 (basal) and 30, 60, 90, and 120 minutes (mins) post consumption. At 30 mins post consumption, HG and C muscular strength was assessed by a 1RM bench press (BP) test followed by lower body power at 60 mins via vertical jump test. Muscular endurance was examined with a 3-set-to-failure BP test at 90 mins. HG exhibited significantly greater BC values (

Training on a Lower Body Positive Pressure Treadmill With Body Weight Support does not Improve Aerobic Capacity

International Journal of Exercise Science 14(7): 829-839, 2021. This study examined the physiological changes resulting from training on a lower body positive pressure treadmill (LBPPT) at three different levels of body weight support (BWS). Thirty-three healthy college aged students (22.3 ± 3.1 years) completed the study. Participants performed a graded exercise test (GXT) to exhaustion and were placed into one of three experimental groups corresponding to 100%, 75%, and 50% of their normal BW. Participants trained at their experimental BW levels for eight-weeks. Training speed was monitored by heart rate (HR) and speed was adjusted to elicit approximately 60% of participant’s peak oxygen uptake (V̇O2peak) at normal BW prior to including body weight support (BWS). One-way analysis of variance (ANOVA) was used to compare the change in aerobic capacity. The 100% BW group improved their relative V̇O2peak (1.42 ± 1.52 ml · min-1 · kg-1) when compared to the 50% BW group (-0.87 ± 2.20 ml · min-1 · kg-1 [p = .022]) but not the 75% BW group (-0.16 ± 1.92 ml · min-1 · kg-1, [p = .14]). Furthermore, no statistical differences in V̇O2peak were observed between the 75% and 50% BW groups (p = .66). Based on this study, training at 75% and 50% of normal BW on a LBPPT does not improve aerobic capacity compared to training with no BWS when using training speeds derived from a GXT with full BW. The outcome of this study may help to prescribe training speeds while utilizing a LBPPT to maintain or improve aerobic capacity

The Prevalence of Physical Inactivity and Low Back Pain in Sedentary Office Employees: A Survey Analysis

Low back pain (LBP) is an increasingly common chronic condition and self-perceived disability that full-time sedentary employees are at risk of being exposed to. Sedentary employees are paid workers who fulfill all or most of their occupational duties seated. Currently, there is very little research available that discusses how physical inactivity affects LBP in sedentary office employees. PURPOSE: The purpose of this study is to: (1) determine the prevalence of LBP pain among sedentary office employees, (2) identify the number of sedentary employees who meet the current physical activity guidelines outlined by the American College of Sports Medicine (ACSM) and mirroring Physical Activity Guidelines for Americans, and (3) to determine the prevalence of LBP amongst physical activity habits in the surveyed population. METHODS: One hundred sixty-four participants completed the 36-question survey. Survey questions assessed past injuries, working history, chair type, exercise history and training frequency, sedentary habits, and pain prevalence and management. RESULTS: The survey found 73.7% of participants experience some level of LBP when seated at work. Additionally, 32.3% of participants were inactive, 57.9% of participants were insufficiently active, 7.9% of participants were active and 1.8% of participants were highly active in accordance with the Physical Activity Guidelines for Americans. Sixty-six participants reported engaging in resistance training with 63.6% reporting LBP. Ninety-five participants reported engaging in aerobic activity with 75.7% reporting LBP. Eighty-nine participants reported engaging in core training with 70.7% reporting LBP. CONCLUSION: The majority of sedentary office employees reported LBP. Additionally, only ~10% of survey respondents met or exceeded ACSM’s Physical Activity Guidelines and LBP was still prevalent in most participants despite their engagement in physical activity

Acute Ultraviolet Light Exposure and Post-Resistance Exercise Serum Testosterone: A Pilot Study in Older Men

International Journal of Exercise Science 13(2): 607-614, 2020. Testosterone deficiency is linked to a multitude of conditions including depression, sexual dysfunction, and cognitive impairment. Although synthetic testosterone-boosting pharmaceuticals have gained wide use, recent data suggests that vitamin D, ingested orally, may positively impact serum testosterone. Furthermore, evidence tying ultraviolet (UV) light exposure to endogenous vitamin D synthesis presents an intriguing possibility for naturally enhancing serum testosterone. This investigation sought to determine the effect of acute UV light exposure on resistance exercise-induced acute testosteronemia and vitamin D in older men. Six older adult men of varying activity levels (age 62 ± 1.79 yrs., height 179.92 ± 1.12 cm., body mass 83.79 ± 3.12 kg., BMI 25.95 ± 1.15 kg/m2) participated in two testing sessions separated by one week: 1) Resistance exercise followed by standard passive recovery (RERC) and 2) RE plus UV light exposure during the first 10-minutes of RE passive recovery (RERC-UV). The RE protocol was identical in both sessions and consisted of four sets of 10RM on leg press, chest press, and back row with 1-minute of rest between sets followed by 30-minutes of post-RE passive recovery. Serum testosterone and vitamin D were measured pre- and post-RE in 5-minute increments during the 30-minute recovery. Analysis of variance revealed neither RE or RERC-UV significantly affected serum testosterone or vitamin D. These findings suggest that acute UV light exposure may be insufficient to positively impact serum testosterone and vitamin D following a single bout of RE in older adult men

A Comparison of Muscle Activation Among the Front Squat, Overhead Squat, Back Extension and Plank

International Journal of Exercise Science 13(1): 714-722, 2020. The purpose of this study was to compare the muscle activation of the scapula, leg, and trunk among the front squat (FS), overhead squat (OHS), back extension (BE) and plank (PL). Seven recreationally trained men (age: 28 ± 3.6 years, body mass: 92 ± 26.1 kg, height: 175 ± 5.3 cm, 3-RM front squat test: 125 ± 49.8 kg, 3-RM overhead squat test: 91 ± 15.5 kg) participated in this within-subject crossover design. Two isometric exercises (plank and Biering-Sorenson back extension) were also included for trunk musculature comparisons. Neuromuscular activitation of the vastus lateralis (VL), biceps femoris (BF), thoracic region of erector spinae (ES), middle trapezius (MT), rectus abdominis (RA), external oblique (EO), serratus anterior (SA), and anterior deltoid (AD). The neuromuscular activity of the FS and OHS were analyzed using a 2 X 3 (squat variation X intensity) repeated measures analysis of variance (ANOVA). Effects were further analyzed by Bonferroni corrected paired t-tests. Results showed that AD activity was significantly greater (p \u3c .05) during the FS compared to OHS at 65 and 95% of the 3-RM, while MT activity was significantly greater (p \u3c .05) during the OHS than the FS at 80 and 95% of the 3-RM. ES activity was significantly greater (p\u3c .05) during both the FS and OHS compared to the BE, but PL elicited significantly greater EO and RA activity than both the FS and OHS. These findings reveal that the FS and OHS can help facilitate the activation of muscles supporting the shoulder complex, scapula and lower back

Comparing Muscle Oxygenation and Maximal Blood Lactate Concentration in Middle-Distance Athletes: A Speed Reserve Ratio Analysis

Middle-distance running is a unique discipline that utilizes both aerobic and anaerobic abilities, resulting in a physiologically diverse athlete population. This diversity in athlete makeup underscores the necessity for precise physiological profiling methods to improve individualized training and race strategy approaches. While the Speed Reserve Ratio (SRR) has garnered attention as an accurate and effective tool in athlete profiling, skeletal muscle oxygenation (SmO2) and blood lactate also have shown potential in this field. However, the effectiveness of these biomarkers in middle-distance populations, especially in conjunction with SRR, is less understood. PURPOSE: This research aims to understand the relationships between SRR, changes in SmO2, and peak blood lactate concentrations in male middle-distance runners. By establishing correlations between these biomarkers, we aim to evaluate their potential to characterize an athlete\u27s aerobic and anaerobic capabilities, which could enhance personalized training and performance optimization. METHODS: Nine male middle-distance runners (age 22.89±2.62 years, weight 71.03±8.42 kg, height 172.03±9.24 cm) were evaluated in two distinct exercise tests. The initial test was a 50m sprint designed to determine max sprint speed (MSS). The subsequent test involved an incremental treadmill protocol that measured VO2 max, max aerobic speed (MAS), the change in SmO2 via a portable near-infrared spectroscopy (NIRS) device, and post-exercise peak blood lactate levels. Pearson correlation coefficients were used to analyze associations. RESULTS: Analysis revealed significant correlations between SRR and VO2max (r = -0.897, p = 0.009), SRR and changes in SmO2 (r = 0.698, p = 0.036), and between SmO2 and MSS (r = 0.756, p = 0.019). CONCLUSION: The correlations establish a strong link between SRR, VO2max, and SmO2 changes. The data suggests that measuring SmO2 can help predict a middle-distance runner’s aerobic and anaerobic capacities, emphasizing its potential as a pivotal biomarker for athlete profiling. Additionally, our findings bolster the SRR\u27s role as a tool for detailed physiological profiling, advocating for its application in athlete evaluation and tailored training recommendations

Comparing Knee Kinetics and Muscular Activity between the Barbell Squat and Flywheel Squat in Recreationally Trained Females

Previous literature has supported flywheel (FW) training with inducing muscular size and strength comparable to resistance training with free weights. However, it remains unclear how the biomechanical demands of these two training methods differ regarding reducing the risk of load-dependent injuries. PURPOSE: With the growing population of female astronauts, this study aimed to compare knee joint kinetics and muscle activation when squatting to full depth on the barbell back (BB) squat and a gravity-independent FW device utilizing technology to be deployed in future long-term space missions. METHODS: Twenty recreationally trained females (22.3 ± 2.7 yrs, 1.6 ± 0.1 m, 59.8 ± 6.8 kg) with at least two years of experience in BB squat training participated in this study. The first session involved one-repetition maximum (1RM) testing on the BB squat and familiarizing the participants with squatting on the FW device (YoYo ™ Multigym). In session two, the participants conducted: 1) one set of seven repetitions at 83% of their 1 RM in the BB and 2) one set of seven maximal repetitions on the FW training device using an inertial load of 0.100 kg ⋅ m2. The order of the exercises in session two was randomized. Three-dimensional motion capture, force platforms, and electromyography assessed knee joint moments and muscle activation on the participants\u27 dominant limb. Paired t-tests were conducted to compare these variables, with a significance set at p ≤ 0.05. RESULTS: Analysis revealed peak knee extensor moments were greater in the BB squat (BB: 2.14 ± 0.36 Nm/kg, p = 0.004; FW: 1.94 ± 0.06 Nm/kg). The BB squat elicited greater mean muscle activity over the set compared to FW squats in the following: (vastus lateralis: +5.68%, p = 0.015; bicep femoris: +4.63%, p \u3c 0.001; gluteus maximus: +4.67%, p = 0.024; gluteus medius: +2.75%, p = 0.011; gastrocnemius lateralis: +3.09%, p = 0.028; gastrocnemius medius: +2.48%, p = 0.024). However, FW squats attained greater tibialis anterior activity (+5.56%, p = 0.04). There was no significant difference in muscle activity observed in the rectus femoris and vastus medialis. CONCLUSION: Although FW training requires less mechanical demand on the knee extensors when squatting to similar depths, participants achieved greater muscular activation during the BB squat

Isokinetic Muscle Strength and Fatigue Evaluation Following a Combined Aerobic and Resistance Training Program on a Gravity Independent Flywheel Device

Exposure to microgravity imposes changes on the musculoskeletal and cardiovascular systems leading to decreases in aerobic capacity, muscular strength, and muscular fatigue (1). Anti-gravity muscles, those that play a postural role in a standard gravity environment such as the soleus and quadriceps, are most affected by microgravity (2) with nearly all musculature affected with extended spaceflight (3). The multi-mode exercise device (M-MED) is a gravity independent device that provides both high force resistance type and low force aerobic type modes of exercise. Consequently, the M-MED has the ability to enhance both skeletal muscle function through resistance training exercises as well as cardiovascular function with aerobic training

Reduced Career Longevity but Return to Baseline Performance After Arthroscopic Shoulder Labral Repair in National Hockey League Players

PURPOSE: To investigate the impact of arthroscopic shoulder labral repair without shoulder instability on career longevity, game use, and performance in National Hockey League (NHL) athletes. METHODS: A retrospective review of all NHL players who underwent arthroscopic shoulder labral repair from 2004 to 2020 was performed. A 2:1 matched control group was used for comparison. Controls were matched by age, body mass index, position, and experience prior to the index year. Demographic characteristics, game use, and performance metrics were collected for all athletes. Statistical analysis examined game use and performance both at 1-year and 3-year follow-up compared with one season before injury. RESULTS: Twenty-nine players who underwent arthroscopic shoulder labral surgery returned to play (100%) and were matched with 55 control players. The operative cohort experienced shorter careers compared with controls (4.4 ± 3.1 vs 6.0 ± 3.6 seasons, P < .05). After one season, injured players experienced significant reductions in goals per 60 (0.6 ± 0.4 vs 0.8 ± 0.5, P = .013), points per 60 (1.5 ± 0.9 vs 2.0 ± 0.9, P = .001), and shooting percentage, (8.5 ± 5.8 vs 10.5 ± 5.2, P = .02) compared with the year prior. The reduction in goals (0.6 ± 0.4 vs 0.8 ± 0.5, P = .01) and shooting % (8.5 ± 4.7 vs 10.5 ± 5.2, P = .04) persisted at 3 years. Compared with controls, the surgical group experienced significant reductions at one season postindex in percentage of goals, assists, points per 60, and shooting percentage. Only the reduction in goals per 60 persisted at 3 seasons postindex. CONCLUSIONS: Following return to play after arthroscopic shoulder labral repair, NHL players demonstrated reduced career longevity compared with healthy controls. Players exhibited significant reductions in game use and performance at one season after injury but returned closer to baseline after 3 seasons. LEVEL OF EVIDENCE: Level III; retrospective case control