In this study we compared Achilles tendon loading parameters during barefoot running among females with different foot strike patterns using open-source computer muscle modeling software to provide dynamic simulations of running. Muscle forces of the gastrocnemius and soleus were estimated from experimental data collected in a motion capture laboratory during barefoot running for 11 runners utilizing a rearfoot strike (RFS) and 8 runners utilizing a non-RFS (NRFS) pattern. Our results show that peak Achilles tendon force occurred earlier in stance phase (p = 0.007), which contributed to a 15% increase in average Achilles tendon loading rate among participants adopting a NRFS pattern (p = 0.06). Stance time, step length, and the estimated number of steps per mile were similar between groups. However, runners with a NRFS pattern experienced 11% greater Achilles tendon impulse each step (p = 0.05) and nearly significantly greater Achilles tendon impulse per mile run (p = 0.06). This difference equates to an additional 47.7 body weights for each mile run with a NRFS pattern. Runners considering a NRFS pattern may want to account for these novel stressors and adapt training programs accordingly.

The incidence of patellofemoral pain (PFP) is 2 times greater in females compared with males of similar activity levels; however, the exact reason for this discrepancy remains unclear. Abnormal mechanics of the hip and knee in the sagittal, frontal, and transverse planes have been associated with an increased risk of PFP. The purpose of this study was to compare the mechanics of the lower extremity in males and females during running in order to better understand the reason(s) behind the sex discrepancy in PFP. Three-dimensional kinematic and kinetic data were collected as male and female participants completed overground running trials at a speed of 4.0 m · s (±5%). Patellofemoral joint stress (PFJS) was estimated using a sagittal plane knee model. The kinematics of the hip and knee in the frontal and transverse planes were also analysed. Male participants demonstrated significantly greater sagittal plane peak PFJS in comparison with the female participants (P < .001, ES = 1.9). However, the female participants demonstrated 3.5° greater peak hip adduction and 3.4° greater peak hip internal rotation (IR). As a result, it appears that the sex discrepancy in PFP is more likely to be related to differences in the kinematics of the hip in the frontal and transverse planes than differences in sagittal plane PFJS.

Study Design Cross-sectional study. Background The drop vertical jump task is commonly used to screen for anterior cruciate ligament injury risk; however, its predictive validity is limited. The limited predictive validity of the drop vertical jump task may be due to not imposing the cognitive demands that reflect sports participation. Objectives To investigate the influence of additional cognitive demands on lower extremity mechanics during execution of the drop vertical jump task. Methods Twenty uninjured women (age range, 18-25 years) were required to perform the standard drop vertical jump task, as well as drop vertical jumps that included additional cognitive demands. The additional cognitive demands were related to attending to an overhead goal (ball suspended overhead) and/or temporal constraints on movement selection (decision making). Three-dimensional ground reaction forces and lower extremity mechanics were compared between conditions. Results The inclusion of the overhead goal resulted in higher peak vertical ground reaction forces and lower peak knee flexion angles in comparison to the standard drop vertical jump task. In addition, participants demonstrated greater peak knee abduction angles when trials incorporated temporal constraints on decision making and/or required participants to attend to an overhead goal, in comparison to the standard drop vertical jump task. Conclusion Imposing additional cognitive demands during execution of the drop vertical jump task influenced lower extremity mechanics in a manner that suggested increased loading of the anterior cruciate ligament. Tasks utilized in anterior cruciate ligament injury risk screening may benefit from more closely reflecting the cognitive demands of the sports environment. J Orthop Sports Phys Ther 2018;48(5):381-387. Epub 10 Jan 2018. doi:10.2519/jospt.2018.7739.

Ghanati, HA, Letafatkar, A, Almonroeder, TG, and Rabiei, P. Examining the influence of attentional focus on the effects of a neuromuscular training program in male athletes. J Strength Cond Res 36(6): 1568–1575, 2022—Neuromuscular training programs that incorporate lower extremity strengthening, plyometric exercises, balance training, and movement retraining are recommended for anterior cruciate ligament injury prevention; however, there is a need to improve their effectiveness. The purpose of this study was to examine how athletes' attentional focus during training influences the effects of an 8-week neuromuscular training program on hip strength, single-leg landing mechanics, and hop performance. Sixty-six male athletes were randomly allocated to a group that trained with an internal focus, a group that trained with an external focus, or a control group. All athletes completed testing before (baseline) and after (posttesting) the 8-week period. Isokinetic hip strength, hip and knee kinematics and ground reaction forces during landing, and hop distance were examined as part of this study. Analysis of covariance was used to compare posttesting outcomes among the groups while accounting for group differences in baseline performance. The neuromuscular training program resulted in improved hip abduction strength, reduced hip adduction and internal rotation motion during landing, and increased hop distance for athletes who trained with an external focus. However, the program did not seem to influence hip strength, landing kinematics, or hop performance for athletes who trained with an internal focus. Our findings indicate that male athletes may benefit from completing a neuromuscular training program with an external focus vs. an internal focus. Trainers, coaches, and clinicians should consider using instructions that promote an external focus when implementing neuromuscular training programs with male athletes.