Salivary Alpha-Amylase in Experimentally-Induced Muscle Pain

Nociception related biomolecules in the adult human saliva: A scoping review with additional quantitative focus on cortisol

Nociception related salivary biomolecules can be useful patients who are not able to self-report pain. We present the existing evidence on this topic using the PRISMA-ScR guidelines and a more focused analysis of cortisol change after cold pain induction using the direction of effect analysis combined with risk of bias analysis using ROBINS-I. Five data bases were searched systematically for articles on adults with acute pain secondary to disease, injury, or experimentally induced pain. Forty three articles met the inclusion criteria for the general review and 11 of these were included in the cortisol-cold pain analysis. Salivary melatonin, kallikreins, pro-inflammatory cytokines, soluable TNF-α receptor II, secretory IgA, testosterone, salivary α-amylase (sAA) and, most commonly, cortisol have been studied in relation to acute pain. There is greatest information about cortisol and sAA which both rise after cold pain when compared with other modalities. Where participants have been subjected to both pain and stress, stress is consistently a more reliable predictor of salivary biomarker change than pain. There remain considerable challenges in identifying biomarkers that can be used in clinical practice to guide the measurement of nociception and treatment of pain. Standardization of methodology and researchers' greater awareness of the factors that affect salivary biomolecule concentrations are needed to improve our understanding of this field towards creating a clinically relevant body of evidence.

Exploring Non-Invasive Salivary Biomarkers for Acute Pain Diagnostics: A Comprehensive Review

Pain is one of the most common complaints leading to a pediatric emergency department visit and is associated with various painful procedures, leading to increased anxiety and stress. Assessing and treating pain in children can be challenging, so it is crucial to investigate new methods for pain diagnosis. The review aims to summarize the literature on non-invasive salivary biomarkers, such as proteins and hormones, for pain assessment in urgent pediatric care settings. Eligible studies were those that included novel protein and hormone biomarkers in acute pain diagnostics and were not older than 10 years. Chronic pain studies were excluded. Further, articles were divided into two groups: studies in adults and studies in children (<18 years). The following characteristics were extracted and summarized: study author, enrollment date, study location, patient age, study type, number of cases and groups, as well as tested biomarkers. Salivary biomarkers, such as cortisol, salivary α-amylase, and immunoglobulins, among others, could be appropriate for children as saliva collection is painless. However, hormonal levels can differ among children in different developmental stages and with various health conditions, with no predetermined levels of saliva. Thus, further exploration of biomarkers in pain diagnostics is still necessary.

Stride Length Impacts on Sagittal Knee Biomechanics in Flat Ground Baseball Pitching

Coordinated lower extremity biomechanics are altered in response to changes in stride length, influencing the kinetic chain that potentially induces compensatory throwing mechanics throughout the baseball pitching cycle. The respective sagittal knee dynamic profiles, for both the stride (lead) and drive (trail) leg, were analyzed during flat ground baseball pitching to determine whether the stride length variation elicits compensatory drive and stride leg knee joint kinematics, kinetics, and joint powers. Using a randomized cross-over design, a cohort of 19 healthy skilled competitive pitchers from collegiate and high school travel programs from across Western New York were assigned to throw 2 simulated 80 pitch games at ±25% of their desired stride length. An integrated motion capture system with two force plates and a radar gun tracked each throw. Pairwise comparisons at hallmark events and phases identified significantly different sagittal knee dynamics for both the drive and stride leg between the stride length conditions. During the acceleration phase, the drive knee moments between the stride length conditions demonstrated differences in power generation and absorption. Longer strides allowed for greater knee propulsion dynamics, exemplified by eccentric drive knee extensor moments with a concomitant power absorption that slowed the rate of drive knee flexion (p ≤ 0.001). Conversely, shorter strides generated power through concentric knee flexor moments that increased the rate of drive knee flexion (p ≤ 0.001). Stride knee extensor moments and power generation during the acceleration phase were also significantly higher with shorter strides (p ≤ 0.05). Adapted knee joint dynamics may offer insights into stride length optimization, training, and injury prevention strategies.