Diagnosis and prognosis for exercise-induced muscle injuries: from conventional imaging to emerging point-of-care testing

Fig. 1. Muscle injuries and mechanisms. (A) Structure of skeletal muscle;96 (B) the muscle performance as time after exercise-induced muscle injury;29 (C) mechanism of exercise-induced muscle injuries.9,10

Fig. 2. Representative methods for muscle injury assessment and diagnosis. Physical examination:97 (A) manual muscle test and (B) accurate and quantifiable assessment of a patient's muscle injury with a proper measurement tool. Imaging analysis:98 (C) ultrasonography and (D) MRI. (E) Electromyography (EMG).99 (F) Blood test.100–102

Fig. 3. Portable devices for muscle injuries assessment. (A) Scheme of a lateral flow test strip.103 (a) Structure of a test strip. (b–d) Detection process of a test strip. Adding sample (b), antigen–antibody binding (c), bindings of particles with and without antigens to test line and control line, respectively (d). (B) Photos of the i-STATs analyzer (a) and its working procedures: sampling (b) and analyzing (c)103 (images courtesy of Abbott Point of Care Inc., NJ, USA). (C) GeneXpert test platform from Cepheid.104 (D) Mobisante ultrasound (http://www.mobisante.com/).16

Fig. 4. Wearable devices for muscle injuries assessment. (A) Wearable biomedical sensors.85 (B) An automated wearable system for muscle fatigue prediction and detection.86 (C) Wearable electronic system integrated with diagnosis unit, therapy module and data storage component: scheme (a) and digital photo (b).87 (D) Perspiration detective: a paper-based microfluidic for measuring ion levels in sweat. Scheme (a) and digital photo (b).105 (E) Integrated wearable circuit board with multiplexed sensors for sweat compound analysis: digital photo of wearable monitoring of a subject in cycling (a) and scheme of the sensor array (b).106 GOx: glucose oxidase. LOx: lactate oxidase.

Fig. 5. To evaluate exercise-induced muscle injuries in the future requires qualified, portable, wearable, and intelligent platforms that enable real-time, long-term, multi-parameter, and online diagnostics. Evaluation of multiple parameters in structure, physiology and biochemistry are presented with imaging, electromyography (EMG) and blood test results, respectively.