Effects of Neuromuscular Training on Muscle Architecture, Isometric Force Production, and Stretch-Shortening Cycle Function in Trained Young Female Gymnasts.

ABSTRACT: Moeskops, S, Oliver, JL, Radnor, JM, Haff, GG, Myer, GD, Ramachandran, AK, Kember, LS, Pedley, JS, and Lloyd, RS. Effects of neuromuscular training on muscle architecture, isometric force production, and stretch-shortening cycle function in trained young female gymnasts. J Strength Cond Res 38(9): 1640-1650, 2024-This study evaluated the effects of a 10-month neuromuscular training (NMT) intervention on muscle architecture, isometric force production, and stretch-shortening cycle (SSC) function. Thirty-seven girls aged 6-12 years were placed into gymnastics + NMT (gNMT; n = 15), gymnastics only (GYM; n = 10), or maturity-matched control (CON; n = 12) groups. The gNMT group followed a 10-month NMT program in addition to gymnastics training, whereas the GYM group only participated in gymnastics training. Isometric midthigh pull (IMTP) and drop jump (DJ) kinetics were measured, in addition to muscle thickness, fascicle length, and pennation angle of the gastrocnemius medialis at baseline and at 4, 7, and 10 months. A 3 × 4 (group × time) repeated-measures ANCOVA (covariate, % predicted adult height) was used to evaluate within-group changes. Significance level was set at p < 0.05. Significant interaction effects were observed in muscle thickness, absolute (PF abs ) and relative peak force (PF rel ) in the IMTP and various DJ variables. The gNMT group demonstrated improvements in muscle thickness, IMTP PF abs and PF rel , and DJ kinetics, most commonly evidenced from 7 months onward. The GYM group's muscle thickness also significantly improved, accompanied by improvements in some DJ kinetics. The CON group did not experience any desirable changes. Overall, NMT elicited positive changes in muscle thickness, PF abs and PF rel , and SSC function to a greater extent than gymnastics training alone or growth and maturation. As most adaptations took 7 months, longer-term NMT programs should be implemented with youth female gymnasts.

The clinical utility and reliability of surface electromyography in individuals with chronic low back pain: A systematic review.

Chronic low back pain (CLBP) is a common disorder worldwide, affecting young and old adults alike. Kinematic studies of lumbar-pelvic mobility allied with surface electromyogram (sEMG) can assist in the assessment and management of CLBP. This systematic review aimed to synthesise the evidence relating to the diagnostic accuracy and reliability of the surface electromyogram in chronic low back pain patients during flexion-extension-relaxation tasks. Five databases (PubMed, Scopus, Web of Science, Embase and CINAHL) were searched for eligible studies from inception to March 2024. The risk of bias assessment for the included studies was conducted using the QUADAS-2 tool. Studies included adults (≥18 years) with CLBP > 3 months, reported diagnostic accuracy or reliability measures for sEMG during flexion-extension-relaxation tasks. Eleven studies were included in our systematic review. The risk of bias was found to be high for patient selection, reference standard and flow and timing domains with low risk of bias for the index test domain in most of the included studies. For diagnostic accuracy, six studies reported values ranging between 56-99 % indicating poor to excellent accuracy levels. Four studies reported values between 76-100 % for sensitivity and 65-100 % for specificity indicating sufficient to excellent accuracy levels. Seven studies reported moderate to excellent reliability levels, ranging between 0.66-0.99. This systematic review found the diagnostic accuracy and reliability of sEMG in CLBP patients to range from poor to excellent levels. This systematic review adds knowledge for practitioners and clinicians regarding the use of sEMG during forward, flexion and relaxation tasks/movements.