Reliability and Differences Between Sexes in Landing Mechanics when Performing the Lateral Bound Test.

Background and Purpose: Anterior cruciate ligament injuries are prevalent among the athletic population, imposing a heavy economic burden, and the risk of re-injury. Most current biomechanical screening tasks are performed in the sagittal plane, and there is a need for more screening tools that assess sports specific movements in the frontal plane. The purpose of this study was to determine the reliability of and examine differences between sexes in the performance of the Lateral Bound Test (LBT). Materials/Methods: Each subject performed three trials of a LBT which included jumping laterally from one leg over a hurdle and landing on the opposite leg. Two cameras were placed six feet from the landing marker. Maximum dynamic knee valgus using the frontal plane projection angle and knee flexion angle at initial contact and maximal knee flexion were measured upon landing leg using 2D video analysis software. Additionally, video of 10 individuals' trials were analyzed twice with one week between the analyses to obtain intra-rater reliability while 12 participants were retested one week later to determine test-retest reliability. Results: Thirty healthy subjects, 16 males, 14 females participated. Intra-rater reliability was determined to be excellent for all variables (ICC>0.96). In contrast, the test-retest reliability had greater disparity. Test-retest reliability ranged from poor (ICC = 0.47) to excellent (ICC > 0.90). Significant differences existed between the sexes, including males being significantly taller, weighing more, and demonstrating greater bilateral dynamic knee valgus (p < 0.05). No significant differences existed between sexes for knee flexion angles. Conclusion: The new LBT had excellent intra-rater reliability for assessing dynamic knee valgus and initial and maximum knee flexion angle when performing a functional movement in the frontal plane. Furthermore, males landed with more dynamic knee valgus than females which is contradictory to what has been observed with functional screening tools performed in the sagittal plane. Level of Evidence: 3b (reliability study).

Overstride-Induced Medial Knee Desmopathy: An Exploration Case Series.

Nine runners with varied experience but similar running-gait forms presented with the insidious and progressive onset of medial knee pain. Functional tightness of the semimembranosus (SM) tendon appeared to be a concomitant factor in the pain presentation of these patients. When evaluating atraumatic medial knee pain in runners, clinicians must consider bone stress injuries and atypical conditions. A functionally tight SM may induce pain and desmopathy of the medial collateral ligament through direct fiber entanglement or cause entrapment of infrapatellar branches of the saphenous nerve or both. Relieving SM tension resulted in short-term pain reduction while eliminating the overstride during the running gait over the long term appeared to prevent recurrence.

INTER-RATER AND TEST-RETEST RELIABILITY OF TWO NEW SINGLE LEG SIT-TO-STAND TESTS.

BACKGROUND: The single leg sit-to-stand test (SLSTST) is a functional test that assesses quadriceps strength. The original SLSTST was used to diagnose lumbar nerve root impingement/radiculopathy - specifically at the L3 and L4 level. The original SLSTST used one repetition as the requirement for a successful test, therefore it may not identify quadriceps weakness in highly functional individuals with or recovering from an athletic injury. PURPOSE/HYPOTHESIS: The purpose of this study was to determine the interrater and test-retest reliability of two new SLSTSTs, one for maximum number of repetitions over 30 seconds and one for time to complete five repetitions. STUDY DESIGN: Cross-sectional, reliability study. METHODS: Twenty healthy college-aged individuals (12 males, age: 22.5 years ± 1.37, height: 1.72 m ± 0.09; weight: 70.2 kg ± 11.0) participated in the study. Two testing sessions were held three to seven days apart, and two second-year physical therapy students served as examiners. The objective of the 30-second SLSTST was for the participant to perform as many single leg sit-to-stand repetitions they could in thirty seconds, while the five repetitions SLSTST measured how quickly the subjects could perform five single leg sit to stand repetitions. Both lower extremities were tested and Intraclass Correlation Coefficients (ICC) were calculated to determine reliability. RESULTS: Both SLSTSTs were found to have excellent interrater and good to excellent test-retest reliability. The 30-second SLSTSTs had inter-rater ICC = 0.99 on the right and 0.98 on the left while the test-retest ICCs ranged from 0.92 to 0.94. The five repetition SLSTSTs had an inter-rater ICC = .99 on both legs while the test-retest ICC ranged from 0.87 to 0.94. CONCLUSIONS: The results of the current study indicate that the two new SLSTSTs had good to excellent test-retest and excellent inter-rater reliability. However, more research is needed to determine if SLSTSTs can be used to identify quadriceps weakness in individuals with recovering from an athletic injury or to be used as a return-to-sport (RTS) assessment. LEVELS OF EVIDENCE: Level 2.

Scapular muscles strength in college baseball players with and without a history of UCL injury.

BACKGROUND: Ulnar collateral ligament (UCL) injuries are common in overhead athletes and have increased in prevalence among baseball pitchers of all ages. The purpose of this study was to examine the difference between the strength of five scapular stabilizing muscles in college baseball pitchers with and without a history of UCL surgery. Data on a pitcher with a recent diagnosis of a Grade I UCL sprain was also included as a case study. METHODS: Thirty-nine college baseball pitchers, eight pitchers with a history of UCL surgery, volunteered to participate. Each participant completed a self-guided warm-up and then the strength of five scapular stabilizing muscles were assessed using a hand-held dynamometer. Station one tested latissimus dorsi and serratus anterior while the middle trapezius, lower trapezius, and rhomboids were assessed at station two. To determine the difference between groups Mann-Whitney U tests were performed with a significance level of P≤0.05. RESULTS: The results showed no significant difference in muscle strength for all five muscle strength tests between the two groups. Although not statistically significant, the injured group averaged greater strength than the non-injured group for all five muscles tested. CONCLUSIONS: The results of this study indicated there was no difference is scapular stabilizing muscle strength between college baseball pitchers with and without a history of UCL surgery. This may be due to proper rehabilitation and rest following the UCL injury. More research is needed to determine the role of scapular stabilizing muscle strength on elbow and UCL injury in college baseball players.

Acute (-)-Epicatechin Consumption: Effects on Local Vasodilation Following Resistance Exercise and High-Intensity Exercise Performance.

(-)-Epicatechin is a polyphenol previously shown to enhance vascular health. The purposes of the current studies were to determine the effect of acute (-)-epicatechin supplementation on local vasodilation in conjunction with resistance exercise (study 1) and on high-intensity exercise performance (study 2). For study 1, 11 men participated in two resistance exercise sessions, where they performed three sets of barbell curls while consuming 200 mg of 98% pure (-)-epicatechin or placebo. Measurements of total serum nitrate/nitrite and brachial artery diameter were acquired at baseline (pre-supplement), 90 min after supplement consumption (post-supplement), immediately post-exercise (post-exercise), and 30 min post-exercise (30 min post-exercise). For serum nitric oxide metabolites, no significant interaction between supplement and time nor significant main effect of time was observed (p = 0.38 and p = 0.20; respectively). For brachial artery diameter, no significant interaction between supplement and time was observed (p = 0.24). A significant main effect of time was observed for brachial artery diameter (p < 0.01) with post-exercise brachial artery diameter significantly greater diameter than all other time points (all p < 0.01). For study 2, six women and five men completed the 15.5 CrossFit® Open Workout three times. A familiarization session was performed first where the workout was performed without the consumption of a supplement. In a randomized, balanced fashion, 100 mg of 98% pure (-)-epicatechin or cellulose (placebo) was consumed two times per day for two days before testing sessions two and three. On the day of testing sessions two and three, 60 to 90 min before completing the workout, 200 mg of the assigned supplement was ingested with water. No significant difference was observed for time to complete the workout between testing sessions (p = 0.49). In conclusion, under the conditions of the current studies, acute (-)-epicatechin supplementation did not augment vasodilation in combination with resistance exercise, nor did it increase exercise performance in humans.

ACUTE EFFECTS OF NEURAL GLIDING ON ATHLETIC PERFORMANCE.

BACKGROUND: Neural mobilization has been used to treat individuals with musculoskeletal and neuromuscular pathologies, but research on neural mobilization in sports rehabilitation is scarce. Furthermore, there have been no studies investigating the effects of neural gliding on sport performance. PURPOSE/HYPOTHESIS: The purpose of this study was to examine the differences between the acute effects of sciatic nerve gliding and lower extremity dynamic stretching exercises on hamstring flexibility and athletic performance. STUDY DESIGN: A cross-sectional, quasi-experimental design with block assignment was used. METHODS: Twenty-seven (16 males, 11 females, age: 23.6 ± 2.65, height (m): 1.74 ± 0.12, weight (kg): 73.73 ± 16.09) healthy college students volunteered for the study. The neural gliding group had 14 subjects and the dynamic stretching group had 13 subjects. Participants performed a jogging or walking up stairs warm up at a self-selected pace prior to testing. Baseline data was obtained for each of the following measurements: bilateral hamstring flexibility using the active straight leg raise test measured by a digital inclinometer, vertical jump height, 20-yard shuttle run and 10 and 20-yard dash sprint. The participants then performed one of the assigned five-minute stretching protocol, bilateral sciatic neural gliding or dynamic stretching of the lower extremities, followed by the post-test data collection of the same measures. RESULTS: There were no significant group by time interaction for any of the six measurements (2 x 2 repeated measures ANOVA). However, significant time differences, pre-test vs post-test for all participants as one group, for right hamstring length (p = .001), left hamstring length (p = .002) and vertical jump (p = .028) were observed. Post hoc paired t-tests found a significant increase between the pre and post-tests in right hamstring flexibility, (p = .011) in the dynamic stretching group and left hamstring flexibility of participants in the neural gliding condition, (p = .004). When analyzing the groups individually, pre-test vs post-test, a significant difference in vertical jump was not observed in either group. CONCLUSION: Similar improvement in hamstring flexibility with both dynamic stretching and neural gliding exercises without a negative effect on three sports performance tests was demonstrated. Therefore, athletic performance will not be negatively affected by a pre-participation warm-up which includes neural gliding, but more research is needed. LEVEL OF EVIDENCE: Level 3.

A Comparison of Machine versus Free-Weight Squats for the Enhancement of Lower-Body Power, Speed, and Change-of-Direction Ability during an Initial Training Phase of Recreationally-Active Women.

The purpose of this study was to examine differences between a free-weight squat (FWS) and machine squat (MS) during an initial resistance training phase for augmentation of performance tests in recreationally active women. Twenty-seven women (22.7 ± 3.5 years) were block-randomized to three groups: FWS, MS, or control (CON) and completed pre- and post-testing sessions consisting of the squat one-repetition maximum (1-RM), vertical jump, pro-agility test, zig-zag change-of-direction (COD) test, and 30-meter sprint. Participants trained two sessions per week for six weeks by performing jumping, sprinting, and COD drills followed by FWS, MS, or no squats (CON). Peak jump power increased for CON (p = 0.03) and MS (p < 0.01) groups. Change in peak jump power was greater for the MS group compared with the FWS group (p = 0.05). Average jump power increased for the MS group (p < 0.01). Change in average jump power was greater for the MS group compared with the CON group (p = 0.04). Vertical jump height, pro-agility, 30-meter sprint, and zig-zag COD tests improved over time (p < 0.01), with no difference between groups (p > 0.05). Machine squat training maximized jumping power compared with FWS training and CON. Both resistance training groups and the CON group improved equally in the pro-agility, 30-meter sprint, and zig-zag COD tests. Machine squat training may provide performance-enhancing benefits of equal or superior value to those obtained with free-weight squat training in recreationally active women during an initial training mesocycle. These findings also stress the importance of task-specific training in this population of untrained women, as the control group improved in terms of performance to the same degree as both resistance training groups.

(-)-Epicatechin Supplementation Inhibits Aerobic Adaptations to Cycling Exercise in Humans.

The purpose of the study was to determine if cycling exercise combined with (-)-epicatechin supplementation was more effective at increasing training adaptations than cycling combined with a placebo. Blood and muscle samples were obtained at rest before and after training to determine the effects of (-)-epicatechin supplementation on total serum antioxidant capacity, skeletal muscle mitochondrial protein content, and skeletal muscle myostatin gene expression. Participants (n = 20) completed two testing sessions separated by 4 weeks of cycle training, with supplementation of 100 mg (200 mg total daily) of (-)-epicatechin or a placebo, twice daily. Data were analyzed using a two-way mixed model ANOVA for each variable and the alpha level was set at p ≤ 0.05. A significant increase was observed for time for relative peak anaerobic power (p < 0.01), relative anaerobic capacity (p < 0.01), and fatigue index (p < 0.01). A significant increase was observed for time for absolute peak VO2 (p < 0.01) and peak power output obtained during the peak VO2 test (p < 0.01). A significant interaction between group and time for relative peak VO2 was observed (p = 0.04). Relative peak VO2 significantly increased over time in the placebo group (p < 0.01), but not in the (-)-epicatechin group (p = 0.21). A significant increase was observed for time for total serum antioxidant capacity (p = 0.01). No interaction or main effect of time was observed for myostatin (p > 0.05). Likewise, no interaction or main effect of time was observed for cytochrome C or citrate synthase (p > 0.05). A significant interaction effect was observed for succinate dehydrogenase (SDH; p = 0.02). SDH content increased significantly for the placebo group (p = 0.03, partial η2 = 0.59), but not for the (-)-epicatechin group (p = 0.81). Further, whereas no difference existed between the groups for SDH at baseline (p = 0.23), SDH content was significantly greater in the placebo group at the post time point (p = 0.01). Results indicate that (-)-epicatechin supplementation does not affect myostatin gene expression or anaerobic training adaptations but inhibits aerobic and mitochondrial SDH adaptations to cycle exercise training.