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  • Author: Jochen Baumeister x
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Linda Paschen, Tim Lehmann, Miriam Kehne and Jochen Baumeister

Purpose: Whereas many studies addressed the relation between acute physical exercise and executive functions (EF) in children, the effects of various modalities of acute exercise on EF still remain unclear. This systematic review investigated the effects of exercise with low and high cognitive demands on speed of processing and accuracy of performance in tasks examining inhibition, working memory, and cognitive flexibility in children. Method: A systematic literature research in electronic databases was performed. Controlled trials assessing the effects of acute exercise on EF in a pre–post design were included. Results: Ten studies involving a total of 890 participants revealed positive effects in working memory performance in speed of processing after acute exercises with low cognitive demands compared with seated rest, mixed results for inhibition after exercises with low and high cognitive demands, and mixed results for cognitive flexibility with low cognitive demands. Concerning accuracy, only mixed results were found for inhibition after exercises with low and high cognitive demands. Conclusion: The differentiated effects of acute exercises with low and high cognitive demands led to more positive effects in speed of processing compared with accuracy of performance. Further investigations including assessment of neurophysiological parameters of EF are needed.

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Alan R. Needle, Thomas W. Kaminski, Jochen Baumeister, Jill S. Higginson, William B. Farquhar and C. Buz Swanik

Context:

Rolling sensations at the ankle are common after injury and represent failure in neural regulation of joint stiffness. However, deficits after ankle injury are variable and strategies for optimizing stiffness may differ across patients.

Objective:

To determine if ankle stiffness and muscle activation differ between patients with varying history of ankle injury.

Patients:

Fifty-nine individuals were stratified into healthy (CON, n = 20), functionally unstable (UNS, n = 19), and coper (COP, n = 20) groups.

Main Outcome Measures:

A 20° supination perturbation was applied to the ankle as position and torque were synchronized with activity of tibialis anterior, peroneus longus, and soleus. Subjects were tested with muscles relaxed, while maintaining 30% muscle activation, and while directed to react and resist the perturbation.

Results:

No group differences existed for joint stiffness (F = 0.07, P = .993); however, the UNS group had higher soleus and less tibialis anterior activation than the CON group during passive trials (P < .05). In addition, greater early tibialis anterior activation generally predicted higher stiffness in the CON group (P ≤ .03), but greater soleus activity improved stiffness in the UNS group (P = .03).

Conclusion:

Although previous injury does not affect the ability to stiffen the joint under laboratory conditions, strategies appear to differ. Generally, the COP has decreased muscle activation, whereas the UNS uses greater plantar-flexor activity. The results of this study suggest that clinicians should emphasize correct preparatory muscle activation to improve joint stiffness in injury-rehabilitation efforts.