Purpose: Trunk function is not only related to physical fitness performance, but also important for the balance, and stability of the whole body. This study aimed to investigate the effects of 2 training methods on trunk stability and athletic performance in adolescent female basketball players. Methods: Fifty-one healthy elite female basketball players (age: 14.76 [1.84] y, body mass index: 21.41 [1.96] kg/m2) were assigned to TRX training (n = 17), Swiss ball training (n = 17), or control groups (n = 17). Participants performed a progressive program of unstable core muscle training consisting of 8 different exercises, with each exercise performed in 3 sets, twice a week for 8 weeks. The outcome measures were a plank test, the modified double leg lowering task, and athletic performance including jumping, speed, agility, cardiopulmonary endurance, and the ankle proprioception. Results: Significant group and time interaction were identified in the modified double leg lowering task (P = .032, η 2 = .134), with post hoc comparisons revealing improvements in the TRX group (P = .014). The TRX group (8.6%) improved significantly more than the Swiss ball group (2.9%) when it comes to the modified double leg lowering average change percentage. The plank test also exhibited a significant group and time interaction (P = .033, partial η 2 = .133), with notable improvements in both the Swiss ball (P = .001) and the TRX groups (P = .001). Athletic performance measures showed no significant differences among groups. Conclusions: The results indicate that both TRX and Swiss ball training can increase core muscle strength and stability without compromising athletic performance after 8 weeks of training. Furthermore, incorporating core muscle training enhances power transmission capabilities. Nevertheless, considering the goal was to improve speed and ankle proprioception during preseason training, careful consideration must be given to the timing and intensity of any intervention involving unstable core muscle training.
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The Effects of Different Core Stability Training on Trunk Stability and Athletic Performance in Adolescent Female Basketball Players
Ian-Ju Liang, Linda L. Lin, and Chen-Chia Huang
Normative Hip Range of Motion and Strength Profiles of Uninjured Baseball Athletes: A Systematic Review
Sean M. Kennedy, Joseph P. Hannon, Reagan M. Morrow, J. Kaylin Kruseman, Frankie-Ann McCauley, Jacob E. Vasquez, James L. Farnsworth, Amanda J. Arnold, and Natalie L. Myers
Context: The baseball athlete incorporates the use of the entire kinetic chain while throwing. Hip range of motion (ROM) and strength have been previously studied in its relation to injury development. It is a clinical necessity to understand the normative profiles of hip musculoskeletal function across the playing career. Objectives: To identify the normative hip ROM and strength profiles of baseball players across level of play. Evidence Acquisition: The researchers searched the electronic databases MEDLINE, SPORTDiscus, CINAHL, and Embase using a custom search strategy. After applying inclusion and exclusion criteria, 31 articles were reviewed. Of these 31 articles, 22 examined hip ROM and/or strength in uninjured baseball athletes. A manual search of the references of those 22 articles revealed 4 additional articles that met the inclusion criteria. In total, 26 articles were included in data collection. Evidence Synthesis: Articles were assessed for quality using the appraisal tool for cross-sectional studies. The appropriate hip ROM and strength data, along with player demographics, were extracted and reviewed to ensure accuracy. Articles were also categorized based on level of play and player position. Conclusions: Hip ROM and strength profiles of baseball athletes across all levels of play were identified and presented to comprehensively summarize the available data on normative musculoskeletal hip profiles. Observed differences between positions and across levels of play were documented. In general, hip external rotation ROM was greater than internal rotation across all levels and between the stance and lead limbs. As age and level of play increased, the difference between hip external rotation and internal rotation ROM also increased. Hip strength increased as level of play (and subsequently age) increased. These summarized data can be used as benchmarks to compare clinical populations.
Walking and Running Biomechanical Dual-Task Cost as Collegiate Athletes Return to Sport Following Concussions Compared to Healthy Controls
Natalie S. Hanno, Robert C. Lynall, and Thomas G. Bowman
The purpose of this study was to examine walking and running biomechanics with and without the addition of a cognitive task in athletes recently diagnosed with concussions. We sought to determine if deficits remained after athletes were asymptomatic, had returned to baseline in all common clinical tests, and had been cleared for full return to sport participation. Seven collegiate athletes with recent concussions (recently concussed) and seven healthy matched controls (controls) completed testing sessions 1–3 days after unrestricted clearance (S1) and 1-week postclearance (S2). Participants completed four gait conditions: (1) walking alone (single task), (2) walking while completing simple mental tasks (dual task), (3) running single task, and (4) running dual task. Participants completed a total of eight walking trials, followed by a total of eight running trials counterbalanced between single- and dual-task conditions. Runscribe™ wearable shoe sensors (Scribe Labs, Inc.) were utilized to assess walking and running gait biomechanics. No significant interaction was found between group (recently concussed, control) and session (S1, S2) for speed (m/s), stride length (m), or step rate (steps/min) during the four gait conditions (p ≥ .34). However, several moderate to large effect sizes were observed for pairwise comparisons (−0.09 ≤ d ≤ 1.72), suggesting clinically meaningful decreased performance in the recently concussed group that would benefit from further study with larger samples.
Erratum. Muscle Torque–Velocity Relationships and Fatigue With Reduced Knee Joint Range of Motion in Young and Older Adults
Journal of Applied Biomechanics
The Influence of Forward Trunk Lean During Single-Limb Landing on Achilles Tendon Force in Physically Active Females
Lee T. Atkins, Hyung Suk Yang, Vaishnavi Chiddarwar, and C. Roger James
It is unknown if forward trunk lean during single-limb landing influences the Achilles tendon force (ATF). This study examined the effect of forward trunk lean during single-limb landing on the ATF in physically active females. Thirty physically active females (23.7 [3.6] y) performed 5 landing trials (0.25 m) using self-selected and forward trunk lean strategies. Dependent variables included peak ATF; average ATF development rate; and sagittal trunk, hip, knee, and ankle angles and moments at the time of peak ATF. The increased forward trunk lean (mean difference (MD) = 14.1°; 95% CI, 11.0 to 17.2; P < .001) caused a decrease in peak ATF (MD = −3.5 N/kg; 95% CI, −5.8 to −1.2; P = .004) and ankle plantar flexion moment (MD = −0.2 N·m/kg; 95% CI, −0.4 to −0.1; P = .002). In contrast, forward trunk lean resulted in greater hip (MD = 15.2°; 95% CI, 11.9 to 18.4; P < .001) and knee flexion (MD = 7.7°; 95% CI , 4.7 to 10.7; P < .001) angles, and hip extension moment (MD = 0.3 N·m/kg; 95% CI, 0.1 to 0.5; P = .002). Forward trunk lean changes predicted peak ATF changes (r = .33, P = .04). Sagittal trunk posture influences the ATF in physically active females during single-limb landing and may effectively alter loading in patients recovering from Achilles tendinopathy.
Influence of Step Rate Manipulation on Foot Strike Pattern and Running Economy
Youngwook Kim, Janae L. Richardson, and Eadric Bressel
Context: With the rise in distance running, there is an increasing interest in reducing running-related injuries and improving performance. Foot strike patterns (FSP) and step rate (SR) are key factors in managing the external forces generated during foot contact in running. Adjusting SR may help alter FSP and improve running economy (RE), yet its effects on recreational runners are not fully understood. Thus, this study aimed to examine if SR manipulations are sufficient to shift FSP and whether the manipulations change the RE. Design: Cross-sectional study. Methods: Eighteen healthy recreational runners’ (age: 30.2 [7.6] y) foot strike angle was calculated using 2D video motion analysis, and submaximal VO2 was measured while running on a treadmill during preferred and adjusted (±5% and ±10%) SR conditions. Foot strike angle was used to predict strike index and quantify FSP, and submaximal VO2 was analyzed to determine RE. Results: Predicted strike index was significantly different between preferred SR and the −10% (P = .002), −5% (P = .002), and +10% (P < .001) SR conditions. Submaximal VO2 was significantly increased in the −10% (P < .001) and −5% (P = .002) SR conditions. Conclusion: SR manipulations were sufficient to alter foot strike angle and predicted strike index in recreational runners, leading to moderate to significant changes in RE. These findings suggest that SR manipulation can be a useful tool for influencing FSPs and optimizing RE to enhance performance and reduce injury risk.
Kinesiophobia in Collegiate Athletes and Nonathletes With and Without Chronic Ankle Instability
Nadia M. Perez, L. Kent Griffin, Randall E. Osborne, and Rachel M. Koldenhoven
Context: Kinesiophobia is a substantial psychological factor that may impact sport performance and activities of daily living for individuals with chronic ankle instability (CAI). The purpose of this study was to determine the levels of kinesiophobia between collegiate athletes and nonathletes with and without CAI using quantitative and qualitative analyses. Design: Cross-sectional survey. Methods: A Qualtrics survey was distributed to college students. Ankle health status was evaluated using the Foot and Ankle Ability Measure Sport subscale, Identification of Functional Ankle Instability, and history questions. Kinesiophobia was assessed using the Tampa Scale of Kinesiophobia-11. A 4 × 2 analysis of variance was used to assess differences in athlete status (NCAA Division 1, intramural, club, and nonathlete) and ankle health status (CAI and healthy). An open-ended question was added to understand how kinesiophobia impacts individuals CAI. Data were analyzed via content analysis. Results: Of the 531 respondents who completed the survey, 140 (116 = CAI and 24 = healthy) met the inclusion criteria for the study. There was a significant main effect for ankle health status for the Foot and Ankle Ability Measure Sport (CAI = 62.68 [15.11]%, healthy = 99.57 [0.01]%), Identification of Functional Ankle Instability (CAI = 21.63 [5.34], healthy = 2.42 [2.93]), and Tampa Scale of Kinesiophobia-11 (CAI = 26.04 [6.22], healthy = 16.75 [5.50]). There were no significant main effects for athlete status or interactions for any variables. Perceptual and behavioral responses were to major categories identified with the qualitative analysis. Fear, pain, and instability were higher order themes within perceptual responses. Activity avoidance and bracing were higher order themes within behavioral responses. Conclusion: This study highlights the significant role of kinesiophobia in individuals with CAI, with those affected reporting higher levels of fear, pain, and instability compared with healthy individuals. Behavioral adaptations such as activity avoidance and bracing were common among qualitative responses. While no differences were observed across athlete statuses, these findings underscore the need for tailored interventions addressing both physical and psychological factors to improve outcomes for individuals with CAI.
Use of Diagnostic Point of Care Ultrasound and Therapeutic Interventions for Knee Pain in a Female Collegiate Volleyball Player: Level 3: Exploration Clinical Case Series Report
Omar A. Ross, Morgan C. Bagley, and Lisa Custer
This is a case of a 19-year-old female Division 1 volleyball athlete with right anterior knee pain assessed using evaluation and diagnostic ultrasound. Anterior knee pain symptomology is commonly found among female jumping athletes. The ultrasound was used to examine the intratendinous changes of the patellar tendon. Hypoechoic changes in the infrapatellar tendon were noted on the right patellar tendon. A 6-week therapeutic intervention was implemented. Postintervention ultrasound assessment showed decreased hypoechoic changes in the right anterior knee. The unique feature of this case is the use of point of care ultrasound in detecting hypoechoic changes within the patellar tendon with therapeutic interventions.
Age Enhances the Effect of Flexibility on Running Economy in Recreational Endurance Runners
Marni G. Wasserman, Amanda C. Melvin, Olivia E. Stump, Samuel I. Reed, Jacob R. Outwin, Joshua Chang, Fiddy Davis, Adam S. Lepley, Kenneth M. Kozloff, and Alexandra F. DeJong Lempke
The primary aims of this study were to determine acute and longitudinal relationships between static flexibility measures and running economy (RE). Seventy-one healthy recreational runners (34 males/37 females, age: 36.4 [12.4] y, body mass index: 23.3 [3.1] kg/m2) completed an aerobic fitness assessment (VO2max) based on self-selected half-marathon race pace (RP) and flexibility testing (standing toe-touch test and weight-bearing lunge test) at baseline and 2 to 3 weeks prior to an endurance running or multisport race (70 [21] d apart). Participants resumed self-selected training and physical activity between laboratory visits. Hierarchical linear regressions were used to assess relationships between flexibility and RE across timepoints, and pre–post changes in flexibility and RE. Interactions between age and flexibility, and experience and flexibility were also investigated. No significant differences (P > .05) were found between flexibility measurements and RE at RP from visit 1 to visit 2, nor were there any significant associations between RE at RP and scores on the weight-bearing lunge test or standing toe-touch test. However, there was a significant interaction between age and the weight-bearing lunge test on RE at RP (ß = −0.0270, P = .018) such that older runners with less flexibility and younger runners with greater flexibility were less economical at RP at baseline. Our findings suggest that reduced flexibility may decrease the energetic cost of running for older runners to a greater extent than it does for younger runners. When prescribing run training intensity and mileage, coaches and clinicians working with masters runners should be cognizant of the potential performance benefits of decreased ankle joint flexibility as well as the overall greater risk of calf injury in this population. Future research should consider the underlying mechanism by which age enhances the beneficial effects of decreased flexibility on RE.
Repeatability of Vertical Ground Reaction Force Estimation During Running on the Athletics Track on 3 Different Days
Bouke L. Scheltinga, Jaap H. Buurke, Joost N. Kok, and Jasper Reenalda
To increase understanding in development of running injuries, the biomechanical load over time should be studied. Ground reaction force (GRF) is an important parameter for biomechanical analyses and is typically measured in a controlled lab environment. GRF can be estimated outdoors, however, the repeatability of this estimation is unknown. Repeatability is a crucial aspect if a measurement is repeated over prolonged periods of time. This study investigates the repeatability of a GRF estimation algorithm using inertial measurement units during outdoor running. Twelve well-trained participants completed 3 running sessions on different days, on an athletics track, instrumented with inertial measurement units on the lower legs and pelvis. Vertical accelerations were used to estimate the GRF. The goal was to assess the algorithm’s repeatability across 3 sessions in a real-world setting, aiming to bridge the gap between laboratory and outdoor measurements. Results showed a good level of repeatability, with an intraclass correlation coefficient (2, k) of .86 for peak GRF, root mean square error of .08 times body weight (3.5%) and Pearson correlation coefficients exceeding .99 between the days. This is the first study looking into the day-to-day repeatability of the estimation of GRF, showing the potential to use this algorithm daily.