The results suggest that balance depends more on muscle quality than on the size of the muscle. The unexpected finding that larger muscle size was associated with increased postural sway and increased fall risk requires further investigation, but highlights the importance of factors besides muscle size in muscle function in older adults.

This paper investigates the hypothesis that a rapidly induced phytochemical response to grazing damage, such as that seen in tomato, serves to deflect insect herbivores away from leaves soon after damaging them (the grazing dispersal hypothesis). As a result, grazing damage is more dispersed than it otherwise would be, and young leaves, which may be of particular importance to a plant in competition for light, are not damaged excessively. In the first experiment, artificial removal of c. 15% of leaf area led to a significant reduction in plant performance compared with undamaged controls, but only when the plants were grown together in competition for light. The second experiment demonstrated that the distribution of grazing damage within the plant was an important factor in the outcome of competition; in those plants in which grazing was applied to the lower leaves there was no effect of damage upon performance compared with undamaged controls, whereas grazing to the upper leaves significantly reduced plant performance. A third experiment provided some insight into how this interaction between damage and competition comes about. It was shown that damage to leaves led to a rapid drop in the rate of extension growth of the main shoot, especially when the upper leaves were damaged, and normal rates of growth were not resumed for at least 3 days. It is argued that in a rapidly growing canopy, such an effect may mean that a damaged plant loses its position in the height hierarchy. The final experiment showed that previous damage to plants can affect the distribution of subsequent grazing by larvae of Spodoptera littoralis, apparently through a wound-induced reduction in leaf palatability. Plants which had been artificially damaged 48 h previously were grazed significantly less than controls, and the avoidance effect was greatest in the young leaves. These results are consistent with the grazing dispersal hypothesis, and suggest that rapid wound-induced responses may be of greatest significance in species characteristic of fertile environments where competition for light is particularly intense.

Background: Quadriceps dysfunction after anterior cruciate ligament (ACL) reconstruction is common and may affect return to sport due to resulting muscle atrophy and muscle weakness. Purpose: To systematically review the available literature regarding the impact of perioperative and postoperative interventions on quadriceps atrophy and loss of strength after ACL reconstruction. Study Design: Systematic review; Level of evidence, 3. Methods: A systematic review was performed in accordance with the 2009 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using PubMed, CINAHL, Cochrane Central, and Embase. The quality of evidence was evaluated using the Modified Coleman Methodology Score to determine consensus scores. Eligible level 1 or level 2 studies included interventions of perioperative nerve block, intraoperative tourniquet use, postoperative nutritional supplementation, and postoperative blood flow restriction training. Additionally, the included studies quantified postoperative quadriceps measurements such as thigh circumference, quadriceps cross-sectional area (CSA), isokinetic quadriceps strength, and/or quadriceps electromyographic (EMG) testing. Results: In total, 15 studies met stated inclusion and exclusion criteria with the following intervention types: perioperative nerve block (n = 4), intraoperative tourniquet use (n = 5), postoperative nutritional supplementation (n = 3), and postoperative blood flow restriction (n = 3). Intraoperative tourniquet use resulted in decreased thigh circumference and detrimental EMG changes in quadriceps function in 3 of the 5 included studies. Perioperative femoral nerve blocks were associated with transient decreases in postoperative quadriceps strength, persisting up to 6 weeks after surgery, in 2 of the 4 studies. Postoperative blood flow restriction training augmented quadriceps size and function after ACL reconstruction in 2 of 3 studies. Postoperative nutritional supplementation was associated with increased quadriceps volume and strength in 1 of the 3 studies examined. Conclusion: The peri- and postoperative factors reviewed here may influence quadriceps atrophy and strength after ACL reconstruction. Our results tentatively indicated that blood flow restriction training may be beneficial to the quadriceps after ACL reconstruction and that intraoperative tourniquet use and nerve block administration may be detrimental; however, the strongest finding was that all of these interventions would benefit from further level 1 and 2 evidence studies, including multicenter, randomized controlled trials with extended follow-up, to definitively determine their impact on return to activity.

Purpose: To perform a systematic review and meta-analysis of literature and to evaluate the relationship between abnormal femoral version and the development of hip osteoarthritis (OA). Methods: A systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, evaluating Level I and II studies. Included studies had to provide granular femoral version (FV) information. The severity of OA was ranked on the KellgreneLawrence (KL) scale. Excel version 1808 (Microsoft, Redmond, WA) was used to perform a student t test statistical analyses. Results: Our review identified 19 qualifying studiesd5 Level I and 14 Level II with 1,756 patients. Patients with FV above normal range (>14 ) had greater KL scores than patients with normal range FV (mean AE standard deviation; 3.37 AE 1.44 vs 2.05 AE 1.72, P < .05). Analysis of KL scores in patients with FV >24 (>1 standard deviation) versus patients with FV >14 but <24 also demonstrated a positive correlation between increasing FV and KL (4.00 AE 1.96 vs 2.34 AE 0). This was significant independent of the presence or absence of developmental dysplasia of the hip. Retroverted hips (FV<10 ) in the present study showed variable OA results upon analysis. Conclusions: The present review suggests that elevated FV may be a risk factor for more severe hip OA with or without the presence of concurrent dysplasia of the hip. The relative amount of increased anteversion appears positively correlated with severity of OA. Although femoral retroversion may impact hip mechanics, in this review it does not appear to strongly correlate with the development of OA. Level of Evidence: II: systematic review of Level I and II studies.

Agreeing on a precise definition of chemical biology has been a persistent challenge for the field. We asked a diverse group of scientists to “define chemical biology” and present a selection of responses.