Effect of Single Set Dynamic and Static Stretching Exercise on Jump Height in College Age Recreational Athletes

This study examined the effects of single set dynamic and static stretching on vertical jump height and hip and knee range of motion in a sample of college age recreational males. Forty-two males (aged 18-24) healthy, physically active volunteers participated as subjects in this investigation and were randomly assigned to one of three groups (1 set of 20 seconds dynamic stretch, 1 set of 20 second static stretch, or control). The knee and hip range of motion, sit and reach, and jump height were measured before and after the treatment condition. The same measures were performed on the control group that sat for 12 minutes. All subjects began with a five minute warm-up on a cycle ergometer. Following the warm-up period, subjects immediately began their stretching program. Results of the investigation showed significant changes from pre-to-post for all dependent measures (p \u3c 0.05). A significant difference between groups was found for sit and reach in the SS + DS groups (p \u3c 0.05). However, there were no significant differences between groups for jump height or knee and hip range of motion. The results of the present study suggest that static and dynamic stretching for 20 seconds prior to a vertical jump can improve vertical jump height and hip and knee range of motion in a sample of male college age recreational athletes. Future research is needed to investigate the effect of single set stretching exercise prior to activities requiring maximal force production that includes athletes and female subjects

Resistance Exercise Reduces Skeletal Muscle Cachexia and Improves Muscle Function in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic, autoimmune, inflammatory disease associated with cachexia (reduced muscle and increased fat). Although strength-training exercise has been used in persons with RA, it is not clear if it is effective for reducing cachexia. A 46-year-old woman was studied to determine: (i) if resistance exercise could reverse cachexia by improving muscle mass, fiber cross-sectional area, and muscle function; and (2) if elevated apoptotic signaling was involved in cachexia with RA and could be reduced by resistance training. A needle biopsy was obtained from the vastus lateralis muscle of the RA subject before and after 16 weeks of resistance training. Knee extensor strength increased by 13.6% and fatigue decreased by 2.8% Muscle mass increased by 2.1%. Average muscle fiber cross-sectional area increased by 49.7%, and muscle nuclei increased slightly after strength training from 0.08 to 0.12 nuclei/μm2. In addition, there was a slight decrease (1.6%) in the number of apoptotic muscle nuclei after resistance training. This case study suggests that resistance training may be a good tool for increasing the number of nuclei per fiber area, decreasing apoptotic nuclei, and inducing fiber hypertrophy in persons with RA, thereby slowing or reversing rheumatoid cachexia

THE EFFECT OF CRYOTHERAPY ON THREE DIMENSIONAL ANKLE KINEMATICS DURING A SIDESTEP CUTTING MANEUVER

Although cryotherapy is commonly used in the treatment of acute and chronic athletic injuries, the deleterious effects of limb cooling, such as decreased nerve and muscle function, slowed sensation and inhibition of normal relaxes, may put an athlete at increased risk of additional injury. The purpose of this study was to determine the effects of cryotherapy on subtalar and ankle joint kinematics of healthy athletes performing a sidestep 45° cut. We hypothesized that greater joint displacements and velocities would be seen after icing. Twenty one subjects performed a 45° sidestep cut prior to and after limb cooling. Retroreflective markers were placed on the subject's shank and foot while 6 high-speed cameras were used to collect the kinematic data. In this test-retest controlled laboratory study, a repeated measures ANOVA was performed on the PRE and POST icing data for the minimum and maximum joint displacements and velocities. No statistical differences were noted between the PRE and POST icing conditions. The results indicate that a 10-minute icing treatment did not have an effect on either the movement patterns or angular velocities. Our results do not support any change in practice of icing injured ankles for ten minutes during halftime of athletic event

Dynamic Stability in Gymnasts, Non-Balance Athletes, and Active Controls

International Journal of Exercise Science 11(1): 1-12, 2018. Gymnastics by nature is a balance sport requiring both static and dynamic stability. To our knowledge, the center of pressure (COP) movement of collegiate gymnasts has not been compared to other collegiate athletes and healthy controls during static and dynamic postural stability tasks. Our purpose was to investigate static and dynamic stability in collegiate gymnasts, non-gymnast athletes and non-athlete controls. Data were collected on female university gymnasts (n=10), university athletes in other sports (n=10), and active non-athlete controls (n=10). Static balance was measured using a commercially available six-condition static test and dynamic plantar/dorsiflexion perturbation test. Static stability variables included: mediolateral and anteroposterior COP sway, total COP displacement, average COP velocity, and standard deviation of vertical force. Dynamic perturbation variables included: initial COP sway, total COP sway, and sway velocity. A two factor ANOVA was performed (group x condition) on each variable (a=0.05) in each assessment. Significant differences were found between the groups for mediolateral COP sway (gymnast

Differences in kinematics and electromyographic activity between men and women during the single-legged squat

Background: Numerous factors have been identified as potentially increasing the risk of anterior cruciate ligament injury in the female athlete. However, differences between the sexes in lower extremity coordination, particularly hip control, are only minimally understood. Hypothesis: There is no difference in kinematic or electromyographic data during the single-legged squat between men and women. Study Design: Descriptive comparison study. Methods: We kinematically and electromyographically analyzed the single-legged squat in 18 intercollegiate athletes (9 male, 9 female). Subjects performed five single-legged squats on their dominant leg, lowering themselves as far as possible and then returning to a standing position without losing balance. Results: Women demonstrated significantly more ankle dorsiflexion, ankle pronation, hip adduction, hip flexion, hip external rotation, and less trunk lateral flexion than men. These factors were associated with a decreased ability of the women to maintain a varus knee position during the squat as compared with the men. Analysis of all eight tested muscles demonstrated that women had greater muscle activation compared with men. When each muscle was analyzed separately, the rectus femoris muscle activation was found to be statistically greater in women in both the area under the linear envelope and maximal activation data. Conclusions: Under a physiologic load in a position commonly assumed in sports, women tend to position their entire lower extremity and activate muscles in a manner that could increase strain on the anterior cruciate ligament

Ground Reaction Forces in 1G and Simulated Zero-Gravity Running

This research compared ground reaction forces during overground (1G) running and zero-gravity ty (0G) simulated treadmill running at a full body weight load in two restraint harness designs

Differences in Kinematics and Electromyographic Activity Between Men and Women during the Single-Legged Squat

Background: Numerous factors have been identified as potentially increasing the risk of anterior cruciate ligament injury in the female athlete. However, differences between the sexes in lower extremity coordination, particularly hip control, are only minimally understood. Hypothesis: There is no difference in kinematic or electromyographic data during the single-legged squat between men and women. Study Design: Descriptive comparison study. Methods: We kinematically and electromyographically analyzed the single-legged squat in 18 intercollegiate athletes (9 male, 9 female). Subjects performed five single-legged squats on their dominant leg, lowering themselves as far as possible and then returning to a standing position without losing balance. Results: Women demonstrated significantly more ankle dorsiflexion, ankle pronation, hip adduction, hip flexion, hip external rotation, and less trunk lateral flexion than men. These factors were associated with a decreased ability of the women to maintain a varus knee position during the squat as compared with the men. Analysis of all eight tested muscles demonstrated that women had greater muscle activation compared with men. When each muscle was analyzed separately, the rectus femoris muscle activation was found to be statistically greater in women in both the area under the linear envelope and maximal activation data. Conclusions: Under a physiologic load in a position commonly assumed in sports, women tend to position their entire lower extremity and activate muscles in a manner that could increase strain on the anterior cruciate ligament

Asymmetric changes in foot anthropometry with pregnancy may be related to onset of lower limb and low back pain.

IntroductionFifty percent of pregnant females experience pain with 20% reporting long-term pain post-partum. Pregnant females undergo changes in foot anthropometry, lower extremity alignment, and joint laxity. It is unknown if asymmetric alterations may be related to development of pain. The purpose of this study was twofold: 1) to compare asymmetric alignment in pregnant females with and without pain during pregnancy and in nulliparous controls and 2) to assess the relationship between asymmetric alignment and pain severity in all participants.MethodsTen pregnant females in their third trimester and nine nulliparous controls participated. Bilateral asymmetry of foot length, width, arch index, arch height index, arch rigidity index, arch drop, rearfoot angle, and pelvic obliquity were determined. Joint laxity and musculoskeletal pain were also assessed. ANOVAs were utilized to compare asymmetries between pregnant females reporting pain (n = 5), those not reporting pain (n = 5), and controls. Spearman's Rho correlations were used to relate asymmetry to pain magnitude (α = 0.05).ResultsNo statistical differences (p>0.05) were found between pregnant females with or without pain and controls for any of the metrics. Negative correlations were found between arch index asymmetry and low back pain (p = 0.005), foot length asymmetry and lower leg pain (p = 0.008), and pelvic obliquity and lower leg pain (p = 0.020). Positive correlations were found between foot width asymmetry and knee pain (p = 0.028), as well as arch drop asymmetry and upper leg (p = 0.024), knee (p = 0.005), and lower leg pain (p = 0.019).ConclusionsThis study was successful in identifying potential targets for prevention and treatment of pain in pregnancy. Furthermore, because pain during pregnancy may be predictive of pain post-partum, it is important to conduct future research to determine both if interventions such as footwear or exercise can prevent or treat these asymmetries and prevent post-partum pain