Effect of citrulline on post-exercise rating of perceived exertion,muscle soreness,and blood lactate levels:A systematic review and meta-analysis

Background:Citrulline is one of the non-essential amino acids that is thought to improve exercise performance and reduce post-exercise muscle soreness.We conducted a systematic review and meta-analysis to determine the effect of citrulline supplements on the post-exercise rating of perceived exertion(RPE),muscle soreness,and blood lactate levels.Methods:A random effects model was used to calculate the effect sizes due to the high variability in the study design and study populations of the articles included.A systematic search of PubMed,Web of Science,and ClinicalTrials.gov was performed.Eligibility for study inclusion was limited to studies that were randomized controlled trials involving healthy individuals and that investigated the acute effect of citrulline supplements on RPE,muscle soreness,and blood lactate levels.The supplementation time frame was limited to 2 h before exercise.The types and number of participants,types of exercise tests performed,supplementation protocols for L-citrulline or citrulline malate,and primary(RPE and muscle soreness)and secondary(blood lactate level)study outcomes were extracted from the identified studies.Results:The analysis included 13 eligible articles including a total of 206 participants.The most frequent dosage used in the studies was 8 g of citrulline malate.Citrulline supplementation significantly reduced RPE(n=7,p=0.03)and muscle soreness 24-h and 48-h after post-exercise(n=7,p=0.04;n=6,p=0.25,respectively).However,citrulline supplementation did not significantly reduce muscle soreness 72-h post-exercise(n=4,p=0.62)or lower blood lactate levels(n=8,p=0.17).Conclusion:Citrulline supplements significantly reduced post-exercise RPE and muscle soreness without affecting blood lactate levels.

Mesenchymal stem cells for enhancing biological healing after meniscal injuries

The meniscus is a semilunar fibrocartilage structure that plays important roles in maintaining normal knee biomechanics and function.The roles of the meniscus,including load distribution,force transmission,shock absorption,joint stability,lubrication,and proprioception,have been well established.Injury to the meniscus can disrupt overall joint stability and cause various symptoms including pain,swelling,giving-way,and locking.Unless treated properly,it can lead to early degeneration of the knee joint.Because meniscal injuries remain a significant challenge due to its low intrinsic healing potential,most notably in avascular and aneural inner two-thirds of the area,more efficient repair methods are needed.Mesenchymal stem cells(MSCs)have been investigated for their therapeutic potential in vitro and in vivo.Thus far,the application of MSCs,including bone marrow-derived,synovium-derived,and adipose-derived MSCs,has shown promising results in preclinical studies in different animal models.These preclinical studies could be categorized into intra-articular injection and tissueengineered construct application according to delivery method.Despite promising results in preclinical studies,there is still a lack of clinical evidence.This review describes the basic knowledge,current treatment,and recent studies regarding the application of MSCs in treating meniscal injuries.Future directions for MSC-based approaches to enhance meniscal healing are suggested.

Anatomy of the anterolateral ligament of the knee joint

Despite remarkable improvements in clinical outcomes after anterior cruciate ligament reconstruction,the residual rotational instability of knee joints remains a major concern.The anterolateral ligament(ALL)has recently gained attention as a distinct ligamentous structure on the anterolateral aspect of the knee joint.Numerous studies investigated the anatomy,function,and biomechanics of ALL to establish its potential role as a stabilizer for anterolateral rotational instability.However,controversies regarding its existence,prevalence,and femoral and tibial insertions need to be addressed.According to a recent consensus,ALL exists as a distinct ligamentous structure on the anterolateral aspect of the knee joint,with some anatomic variations.The aim of this article was to review the updated anatomy of ALL and present the most accepted findings among the existing controversies.Generally,ALL originates slightly proximal and posterior to the lateral epicondyle of the distal femur and has an anteroinferior course toward the tibial insertion between the tip of the fibular head and Gerdy’s tubercle below the lateral tibial plateau.