Background: Individuals who experience a subsequent ipsilateral anterior cruciate ligament (ACL) reinjury may use hazardous muscle activation strategies after primary ACL reconstruction (ACLR). The purpose of this study was to compare electromyograms (EMGs) of the quadriceps, hamstrings, and gastrocnemius muscles during a dynamic hopping task among individuals with a single ACL injury (ACLx1), individuals who went on to have secondary ipsilateral ACL injury (ACLx2), and individuals who have never sustained an ACL injury (ACLx0). Hypothesis: We expected that individuals who went on to experience a secondary ACL injury would use less quadriceps muscle activity as compared with individuals who experienced a single ACL injury. Study Design: Cross-sectional study. Level of Evidence: Level 3. Methods: Fourteen individuals that were returned to play post-ACLR and 7 non-ACL-injured individuals participated. Individuals who had undergone an ACLR were placed into groups depending on whether they had experienced a secondary ipsilateral ACL reinjury postprimary ACLR. EMG data of the vastus lateralis, biceps femoris, and lateral gastrocnemius were measured during 2 phases of a single-leg dynamic hopping task: preactivity (100 ms prior to ground contact) and reactivity (250 ms post–ground contact). Processed EMG data were compared across groups using 1-way analyses of variance, with post hoc independent t tests where appropriate ( P ≤ 0.05). Results: At preactivity, ACLx1 (0.48% ± 0.2%max) was found to use significantly more hamstring activity than ACLx2 (0.20% ± 0.1%max, P = 0.018), but not than ACLx0 (0.38% ± 0.1%max, P > 0.05). At reactivity, both ACL groups were found to use less quadriceps activity than ACLx0 (ACLx1: 0.38% ± 0.1%max, P = 0.016; ACLx2: 0.40% ± 0.1%max, P = 0.033; ACLx0: 0.58% ± 0.1%max), but not than each other ( P > 0.05). Conclusion: Quadriceps muscle activity during landing was diminished in all ACL participants as compared with participants who had never sustained an ACL injury. Individuals who did not experience a secondary ipsilateral ACL reinjury (ACLx1) used greater levels of hamstring activity prior to landing. Clinical Relevance: The higher hamstring activity in patients who did not experience a secondary injury may be interpreted as a protective mechanism that is used to dynamically stabilize the reconstructed limb.
College student members of Greek Letter Organizations (GLOs) report high levels of alcohol consumption, which is associated with adverse academic and health consequences. Those who report lower consumption also report counting their drinks, which requires the ability to identify and pour standard servings of alcohol, skills college students generally lack. Behavioral skills training (BST) has been used to teach students to pour standard servings of beer. However, little is known about whether BST is effective when used in a small‐group format or with other alcohol types, and whether skills generalize across time and novel cups. We used a nonconcurrent multiple baseline design to address these gaps. After receiving small group BST, all participants poured beer accurately, most poured accurately at follow‐up, and about half poured accurately into a novel cup. After receiving individual BST, participants' pours of liquor were variable and most required additional training.
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