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Synchronized Exercise Training Uniquely Influences Glucose Tolerance, Hemodynamics, and Cognition in People with Prediabetes or Type 2 Diabetes.
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The Effect of Functional Training on Dynamic Knee Valgus of Youth Soccer Players. A pilot study
Get PDFInternational Journal of Exercise Science 18(7): 561-574, 2025. Knee injuries are very common in soccer players. High loads on the knee during landing or changes of direction can lead to a valgus shift of the knee, known as Dynamic Knee Valgus (DKV). Many studies have shown that a large shift in DKV is a predisposing factor for knee injuries and disease, such as anterior cruciate ligament injury (ACL), patellofemoral pain syndrome or osteoarthritis. Functional training could be a great tool to reduce DKV. Thus, in this pilot study, nine male youth soccer players (mean age: 16.4 ± 0.2 years) took part in six weeks of functional training program. DKV was measured in pre- and post-measurements during single leg squats using Kinect Azure camera with DynaKnee software. In addition, maximal voluntary muscle contraction (MVC) was measured using a dynamometer and muscle activation amplitude (MAA) was measured using electromyography. Data were analysed using a non-parametric Wilcoxon signed rank test to assess differences in DKV, MAA and MVC at a 5% significance level. Data showed a small improvement of DKV in the dominant leg. MVC increased slightly in all variables. The MAA of the involved muscles in the single-leg squat did not show a higher value, but rather a decreasing trend. However, none of the analyses showed significant changes. The small number of participants and the short duration of the training might have been a limiting factor. Further studies should repeat the procedure with a larger group of participants and a longer training period
EFFECTS OF ANAEROBIC FATIGUE ON TOTAL-BODY BIOMECHANICS USING MARKERLESS MOTION CAPTURE SYSTEM
No full textPURPOSE: This study compared the effects of various anaerobic fatigue tests [i.e. repeated jump test (RVJ), Resisted Sprint (RS), and control (CON)] using the Soccer Performance Assessment Scores (SPAS) in a markerless 3-dimesional motion capture system (MCS). METHODS: Fourteen women collegiate division two soccer athletes (age=21.81.6yrs., hgt.=167.74.6cm, wgt.=66.07.2kg) volunteered. Subjects were screened using the SPAS, consisting of 14 motions. Including shoulder abduction and adduction, horizontal abduction and adduction, internal and external rotation, flexion and extension, reverse lunge, overhead bilateral squat, forward lunges, lateral lunges, single-leg balance, bilateral vertical jump (VJ), unilateral VJ, depth VJ, lateral hop, and multi-unilateral VJ. The 3-D MCS (DARI Motion, Overland Park, KS) was used to analyze the kinetic and kinematic data, from which 192 variables were calculated and reported in the SPAS (Quality, Performance, and Overall). These scores are determined across all of the motions evaluated. Quality evaluates the execution of all motions. Performance evaluates the effectiveness, and Overall is a combination of the previous scores. Each subject completed three randomized experimental sessions (i.e. CON, RVJ, RS). The SPAS was collected pre- and post-session. During the RVJ test each subject was instructed to bend the knee to about 90 degrees and continue to jump explosively on landing for 10 sets. Each set consisted of 15 sec jumping and 15 sec rest. During the RS test each subject was instructed to complete a sprint on a resisted treadmill (Woodway, Waukesha, WI) with 18% of body mass resistance for 30 seconds. Statistical analyses were conducted on the SPAS (Quality, Performance, and Overall) x condition (RVJ, RS, CON) x time (pre-test, post-test) repeated measures MANOVA. RESULTS: The MANOVA indicated a two-way interaction time x score. Follow-up two-way ANOVA and pairwise comparisons indicated significant differences between the Performance and Overall among CON. In addition, significant differences between the Performance among RVJ (Table 1). CONCLUSION: The current investigation demonstrated the viability of a MCS test to evaluate changes in performance due to acute fatigue and determined acute lower-body biomechanical alterations following the RVJ
THE EFFECT OF STATIC STRETCHING ON ACUTE LOWER BODY POWER
No full textEvidence suggests that static stretching prior to jumping may negatively impact acute lower body power. PURPOSE: To examine the effect of acute static stretching on jump performance in physically active individuals. METHODS: Ten physically active, former high school athletes (ages 18-25 yrs, M = 20) participated in the study. The study included three sessions separated by at least 24 hours. The first session was a familiarization session followed by two training sessions (stretch or no-stretch) wherein the participant’s passive hip range of motion and jumping performance was assessed. The participant’s first training session was randomly assigned to either stretch or no-stretch to counter the order effect. Each session included a ten-minute warm up on a cycle ergometer. The static stretch protocol included the glute figure-four, straight leg hamstring, and prone quad stretch. Three sets of each stretch were completed utilizing a 30sec hold time. Passive hip flexion and extension range of motion were measured using a goniometer. Jump performance was assessed using ten vertical jumps followed by five horizontal jump trials to find peak jump height and distance, respectively. The highest three jump scores were averaged and recorded for the vertical jump, and the longest jump distance was recorded for the horizontal jump. RESULTS: There was a non-significant decrease in vertical jump performance after static stretching (Stretch = 20.6±4.1in vs No-Stretch = 21.4±4.7in, p = 0.053) and no difference in broad jump performance between conditions (Stretch = 96.3±13.3in vs No-Stretch = 97.7±12.1in, p = 0.38). CONCLUSION: Static stretching done immediately before jumping does not impair acute lower body power in college-aged, former high school athletes. However, while not statistically significant, the difference in vertical jump performance after static stretching was reduced on average by ~1in and may have practical relevance. Individual responses to the stretch protocol suggest that any benefit or impairment to acute lower body power might be influenced by the individual’s initial level of passive muscle stiffness
SMARTPHONE-ASSESSED, OVERGROUND GAIT SPEED IS ASSOCIATED WITH TANDEM GAIT COMPLETION TIME AMONG ADOLESCENTS POSTCONCUSSION
No full textTandem gait (TG) is a commonly used clinical assessment for evaluating motor-cognitive function and dynamic postural control after concussion. Self-selected, walking gait (WG) temporal-distance metrics may provide similar information to TG outcomes with improved ecological validity. PURPOSE: To investigate associations between single-task (ST) and dual-task (DT) TG and WG among adolescents after recent concussion. METHODS: We conducted a cross-sectional study of adolescents within 21 days of concussion. Participants completed a timed TG test on a 3-meter path and WG along a 10-meter path for one-minute; both were performed under ST and DT conditions. WG temporal-distance metrics were collected using a novel smartphone application (IMPROVE, Control One LLC). Primary outcomes were ST and DT TG completion time and ST and DT WG speed. We calculated pairwise correlation coefficients (Pearson r) between TG and WG outcomes. We used multivariate linear regression, adjusting for symptom severity, time since concussion, age, and sex to further assess the relationship between TG and WG outcomes. RESULTS: We enrolled and tested 82 participants (15.6 ± 2.1 years, 49% female; 12.7 ± 4.4 days since concussion). In unadjusted and adjusted analyses, there was a significant, weak, negative correlation between ST TG completion time and ST WG speed and a significant, moderate, negative correlation between DT TG completion time and DT WG speed (Figure). CONCLUSION: TG completion time and WG speed were significantly correlated in both ST and DT conditions among adolescents with recent concussion. These results suggest that WG could serve as a useful proxy for TG but may also provide unique information for clinical concussion care. Funding sources: Eunice Kennedy Shriver National Institute of Child Health & Human Development (R01HD108133) Undergraduate Poster Blitz WINNE
DIFFERENTIAL EXPRESSION OF MYOSTATIN AND ATROGIN-1 IN STRIATED MUSCLE EXPOSED TO HYPOXIA
No full textHypoxia is characterized by an inadequate supply of oxygen to the body’s tissues occurring when traveling to or residing at high altitudes. The response to hypoxia is tissue-dependent, and in striated muscle (cardiac muscle -right and left ventricles and skeletal muscle), hypoxia exposure results in different hypertrophic and atrophic responses that are striated muscle dependent. In response to hypoxia, the right ventricle (RV) undergoes hypertrophy, the left ventricle (LV) remains mass stable, and the skeletal muscle (SkM) undergoes atrophy. PURPOSE: To determine mechanisms of differential hypertrophy/atrophy in the RV, LV, and SkM in response to acute and chronic hypoxia. METHODS: Male and female C57BL6 mice were placed in a hypobaric hypoxia chamber (HH; 17,000’) for four weeks (chronic hypoxia), three days (acute hypoxia), or remained at ambient air (control; 7220’). Tissue samples from the RV, LV, and the hind limb muscle complex (SkM), were collected. Reverse transcription polymerase chain reaction (qRT-PCR) was used to measure expression of myostatin (MSTN), a negative regulator of hypertrophy, and atrogin-1, a regulator of muscle protein breakdown. RESULTS: The expression of MSTN in SkM and the LV were unchanged in acute or chronic hypoxia. MSTN expression in the RV was unchanged in acute hypoxia but was upregulated fourfold compared to control with chronic hypoxia (p\u3c0.001). Atrogin-1 expression was unchanged across all three muscle types. CONCLUSIONS: Although we establish that changes in muscle mass are tissue dependent, the mechanisms remain unclear but may involve differential activation of MSTN. Understanding these changes may help treat hypoxic disease and translate to individuals living at or journeying to high altitude
IDENTIFYING UPREGULATED MOLECULAR MEDIATORS VIA RNA-SEQUENCING IN EXERCISE-INDUCED ENTRAINMENT OF CIRCADIAN RHYTHMS
No full textA disrupted circadian rhythm compromises the health and well-being of individuals by inducing a series of physiological responses linked to several non-communicable diseases. This study explored how exercise during a disrupted circadian rhythm can re-entrain the misaligned central clock of the suprachiasmatic nucleus (SCN), the control center of such rhythms. Existing literature identifies that supplementation of chrono-timed exercise can induce a phase shift in peripheral clocks; however, more studies are needed to evaluate the role of exercise on the circadian alignment of the central clock. Preliminary data indicates positive exercise-induced changes in the SCN when subjects participated in chrono-timed exercise. PURPOSE: This study aimed to identify mechanisms via RNA-sequencing analysis by which chrono-timed exercise during circadian rhythm disruption can re-entrain the misaligned central clock. METHODS: This work was approved by the University of Wyoming IACUC. This study employs RNA-sequencing of n=16 male and n=16 female mice subjected to either a disrupted circadian protocol with or without chrono-exercise to identify upregulated receptors of molecular mediated pathways, specifically neuropeptide Y (NPY) and serotonin (5-HT) which have been implicated in neural pathways of activity. The animals’ brains were dissected, the SCNs were extracted (“punched”), and the tissue was sent for analysis. RESULTS: The most abundant cell types identified by RNA- sequencing were inhibitory, excitatory, astrocytes, and oligodendrocytes. Prominent upregulation of excitatory and inhibitory cell types indicated further examination. The data established a key focus on 10 genes expressed in excitatory and inhibitory cell types, marked by immense upregulation and a potential link to the circadian system. CONCLUSION: Inhibitory cell types were more robust in females who underwent disruption protocol potentially due to disruption of the circadian system. Excitatory cell types were only expressed in male exercise groups regardless of disruption. Further research is needed to establish these connections by examining six genes of interest that potentially play an important role in circadian realignment via supplementation of chrono-timed exercise. This work was supported by NIH Grant 2P20GM12131006. Master’s Student Poster Honors WINNE