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The aim of this study was to investigate the effects of guarana supplementation on cognitive performance before and after a bout of maximal intensity cycling, and to compare this to an equivalent caffeine dose. Twenty-five participants completed the randomised double-blind crossover trial by performing cognitive tests with 1 of 3 supplements, on 3 different days: guarana (125 mg/kg), caffeine (5 mg/kg) or placebo (65 mg/kg protein powder). After 30-minutes of rest, participants performed simple (SRT) and choice reaction time (CRT) tests, an immediate word recall test and Bond-Lader mood scale. This was followed by a cycling V̇O2max test, cognitive tests were then immediately repeated. Guarana supplementation decreased CRT before exercise (407 ± 45ms) in comparison to placebo (421 ± 46ms, P=.030) but not caffeine (417 ± 42ms). SRT after exercise decreased following guarana supplementation (306 ± 28ms) in comparison to placebo (323 ± 32ms, P=.003) but not caffeine (315 ± 32ms). Intraindividual variability on CRT significantly improved from before (111.4 ± 60.5ms) to after exercise (81.85 ± 43.1ms) following guarana supplementation, no differences were observed for caffeine and placebo (P>.05). Alertness scores significantly improved following guarana supplementation (63.3 ± 13.8) in comparison to placebo (57.4 ± 13.4, P=.014) but not caffeine (61.2 ± 12.8). There were no changes to V̇O2max, immediate word recall or any other Bond-Lader mood scales. Guarana supplementation appears to impact several parameters of cognition. These results support the use of guarana supplementation to possibly maintain speed of attention immediately following a maximal intensity exercise test (V̇O2max).

Background: Patients undergoing unicompartmental knee arthroplasty (UKA) often want to return to sport (RTS) after surgery. However, the time taken to RTS and proportion of patients who RTS after UKA remain unknown. Purpose: To determine the time to RTS and proportion of patients who RTS after UKA. Study Design: Systematic review; Level of evidence, 4. Methods: A search was performed using PubMed, Medline, Embase, SPORTDiscus and the Cochrane Library databases for clinical trials reporting on RTS after UKA published between database inception and September 2021. In addition, a manual search was performed of relevant sports medicine and orthopaedic journals, and bibliographies were reviewed for eligible trials. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were used to undertake this study. Results: This meta-analysis included 11 studies (749 patients) that reported on RTS after UKA. The proportion of patients returning to sports increased over time: 6 studies (432 patients) demonstrated an overall pooled proportion of 48.1% (95% CI, 36.3%-60.2%) of patients who returned to sport at 3 months after surgery, while 7 studies (443 patients) demonstrated an overall pooled proportion of 76.5% (95% CI, 63.9%-87.1%) of patients who returned to sport at 6 months after surgery. Overall, 92.7% (95% CI, 85.8%-97.4%) of 749 patients were able to RTS at 4 years after surgery. Overall excellent patient-reported functional outcomes scores and low risk of complications with RTS after UKA were reported. Conclusion: The authors found that 48.1% of patients were able to RTS at 3 months after surgery and 76.5% were able to RTS at 6 months after UKA. Pooled proportion analysis showed that >90% of patients undergoing UKA were able to RTS at 48 months after surgery. The majority of patients who were able to RTS after UKA did so at a lower level of intensity than their preoperative level. RTS after UKA was associated with good patient-reported functional outcomes scores and a low risk of complications.

Introduction: Total Hip Arthroplasty (THA) is being increasingly undertaken in younger and more active patients, with many of these patients wanting to return to sport (RTS) after surgery. However, the percentage of patients RTS and time at which they are able to get back to sport following surgery remains unknown. The objective of this meta-analysis was to determine the time patients RTS after THA. Methods: A search was performed on PUBMED, MEDLINE, EMBASE, and the Cochrane Library for trials on THA and RTS, in the English language, published from the inception of the database to October 2020. All clinical trials reporting on to RTS following THA were included. Data relating to patient demographics, methodological quality, RTS, clinical outcomes and complications were recorded. The PRISMA guidelines were used to undertake this study. Results: The initial literature search identified 1720 studies. Of these, 11 studies with 2297 patients matched the inclusion criteria. 3 studies with 154 patients demonstrated an overall pooled proportion of 40.0% (95% CI, 32.5–47.9%) of patients RTS between 2 and 3 months after surgery. 4 studies with 242 patients demonstrated an overall pooled proportion of 76.9% (95% CI, 71.5–82.0) of patients RTS by 6 months after surgery. Pooled proportion analysis from 7 trials with 560 patients demonstrated 93.9% (95% CI, 82.7–99.5%) of patients RTS between 6 and 12 months after surgery. Conclusions: Pooled proportion analysis showed increasingly more patients were able to RTS after THA over the first 1 year after surgery. There remains marked inter and intra-study variations in time for RTS but the pooled analysis shows that over 90% of patients were able to RTS at 6–12 months after THA. These finding will enable more informed discussions between patients and healthcare professionals about time for RTS following THA.

We have read the recent systematic review and meta-analysis by Hack et al. [...]

Physical exertion is sometimes associated with changes in cognitive function. However, there is a dearth of literature on the physiological basis of these associations. PURPOSE: To determine the acute effects of intense physical exercise on executive function and prefrontal cortex brain activity, and the impact of baseline fitness on these associations. METHODS: 103 participants (F = 29, M= 74; Age = 40 ± 8) completed tests of executive function before and after undergoing a VO2max test with a Bruce Treadmill Protocol. A comparison control group of 32 participants matched for age, birth sex and fitness completed the same tests before and after active rest. Body fat % was determined via bioelectrical impedance and VO2max via gas analysis. The cognitive tests measured reaction time, control inhibition, stimulus-oriented & stimulus-independent thought, and source memory. Brain activity of the prefrontal cortex was measured during the pre-and post-exercise cognitive tests using functional Near Infrared Spectroscopy (fNIRS). RESULTS: The cohort's mean body fat was 25 ± 7 %, Anaerobic Threshold (AT) was 28 ± 5 ml/kg/min and VO2max was 38 ± 7 ml/kg/min.At baseline, there was no association between body fat % or VO2max and cognitive test performance. However, after exercise, participants showed significantly improved cognitive speed with no decrease in accuracy (F = 28.1; p<.001). The degree to which individual participants showed this exercise-related cognitive enhancement was reflected in changes in oxygen utilisation in the prefrontal cortex, in the regions associated with performances on the individual tasks, beyond those occurring in the no-exercise control group (n = 92, α < .05, FDR corrected). In addition, the exercise-related cognitive speed improvements were significantly negatively associated with body fat % (R 2 = 11.4%; p = .001) and with age (R 2 = 11.0%; p = .001) and were positively correlated with VO2/kg at AT (R 2 = 6.9%, p = .008) and VO2max (p = .003). CONCLUSION: Exercise improved prefrontal cortex brain activity and cognitive processing speed with no detriment to accuracy in executive function in healthy adults. Although all participants improved after exercise, those with a higher body fat percentage, lower cardiovascular fitness and older age showed proportionally less improvement.

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