Electromyographic Assessment of Anterior Cruciate Ligament Injury Risk in Male Tennis Players: Which Role for Visual Input? A Proof-of-Concept Study

Abstract

Anterior cruciate ligament (ACL) injury incidence is often underestimated in tennis players, who are considered as subjects conventionally less prone to knee injuries. However, evaluation of the preactivation of knee stabilizer muscles by surface electromyography (sEMG) showed to be a predictive value in the assessment of the risk of ACL injury. Therefore, this proof-of-concept study aimed at evaluating the role of visual input on the thigh muscle preactivation through sEMG to reduce ACL injury risk in tennis players. We recruited male, adult, semiprofessional tennis players from July to August 2020. They were asked to drop with the dominant lower limb from a step, to evaluate—based on dynamic valgus stress—the preactivation time of the rectus femoris (RF), vastus medialis, biceps femoris, and medial hamstrings (MH), through sEMG. To highlight the influence of visual inputs, the athletes performed the test blindfolded and not blindfolded on both clay and grass surfaces. We included 20 semiprofessional male players, with a mean age 20.3 ± 4.8 years; results showed significant early muscle activation when the subject lacked visual input, but also when faced with a less-safe surface such as clay over grass. Considering the posteromedial–anterolateral relationship (MH/RF ratio), tennis players showed a significant higher MH/RF ratio if blindfolded (22.0 vs. 17.0% not blindfolded; p < 0.01) and percentage of falling on clay (17.0% vs. 14.0% in grass; p < 0.01). This proof-of-principle study suggests that in case of absence of visual input or falling on a surface considered unsafe (clay), neuro-activation would tend to protect the anterior stress of the knee. Thus, the sEMG might play a crucial role in planning adequate athletic preparation for semiprofessional male athletes in terms of reduction of ACL injury risk.

Drop Jumping on Sand Is Characterized by Lower Power, Higher Rate of Force Development and Larger Knee Joint Range of Motion

“…These factors eventually result in increased work expenditure. Furthermore, recent research evidence suggests the existence of an additional protective neuromuscular mechanism when “dealing” with landings on harder, less “safe” surfaces, guaranteed even by visual input alone [ 56 ].…”

Neuromuscular Impairment of Knee Stabilizer Muscles in a COVID-19 Cluster of Female Volleyball Players: Which Role for Rehabilitation in the Post-COVID-19 Return-to-Play?

“…The primary outcome was the pre-activation time of the knee stabilizer muscles of the dominant leg: rectus femoris (RF), vastus medialis (VM), biceps femoris (BF), and medial hamstrings (MH) were evaluated through sEMG. We placed the electrodes on the dominant leg [41,42], according to the recommendations of the sEMG recommendations for Not-Invasive Assessment of Muscles (SENIAM) [44]. The knee stabilizer muscles' time of preactivation is computed as the interval of time between the beginning of muscle activation and the contact with the floor, evaluated by sEMG (FREE EMG 1000; BTS Bioengineering Spa, Garbagnate M.se-Milano, ITA), through 80 mm bipolar surface electrodes (Ambu, Neuroline, Ballerup, Denmark) [45].…”

“…In this context, surface EMG (sEMG) integrated with inertial measurement unit (IMU) provides an insight into how the neuromuscular system behaves [39]. More in detail, it is possible to determine the timing of muscles excitation, describing when a muscle "turns on" [39,40] and to record muscle activity of the quadriceps and hamstrings to determine the recruitment pattern and the time of pre-activation as the time of initial contraction in preparation of landing [41,42]. Moreover, bioelectrical impedance analysis (BIA) represents an accurate method in the assessment of athletes body composition when compared with reference techniques (dual X-ray absorptiometry (DXA)) [43].…”

Pharmacological Treatment for Acute Traumatic Musculoskeletal Pain in Athletes

“…In contrast, the most used analgesics, including non-steroidal anti-inflammatory drugs, acetaminophen, local anesthetics, and tramadol are not forbidden according to the WADA list of prohibited substances [84,186]. However, potential ergogenic effects of NSAIDs in sports performance have been recently reported, and, unfortunately, a significant difference between the use of NSAIDs in-competition vs. out-of-competition has been demonstrated, probably related to the postulated effects in improving physical performance [186][187][188][189][190][191]. Interestingly, performance enhancement seems to be related to the widely noted antalgic effect, which might improve exercise-induced pain level tolerance with consequent positive effects in sports performance [190].…”