Delayed Onset of Muscle Soreness (DOMS) represents the micro-trauma in the muscle [1] characterised by the feeling of pain, discomfort, and decreased range of motion (ROM), which is induced 1 to 2 days after high-intensity exercise [2]. It is also determined as a grade-1 muscular injury in general, seen in recreational or amateur athletes [3]. Sometimes, DOMS appear after unaccustomed eccentric muscle contraction and unfamiliar exercise [4, 5]. Some studies suggested that isometric [6] and forceful concentric work cause a lesser extent of DOMS [7]. DOMS refers to the sensation of soreness, pain, stiffness, swelling, and reduced muscle function, which might impair the capacity for performance. The symptoms of DOMS have a regular progression from weakness and discomfort after exercise. The pain progresses after 24 hours; peak pain intensity is seen in 48 to 72 hours. The pain intensity is mitigated within 7 to 10 days after exercise [8]. In sports overload, skeletal muscle injuries are more common, and it describes incidence near about 10–55% of all sports-related injuries [9]. Though DOMS is not severe muscle damage, it usually causes a harmful impact and compromises sports performances. There is a lack of epidemiological evidence to demonstrate the overall view, as most of the time, DOMS remains undiagnosed and unassessed cases [10].
There are several mechanisms by which DOMS can be described, such as muscle spasm, lactic acid formation, connective tissue and muscle damage, muscle inflammation, and enzyme efflux theory [11]. The most known mechanism of DOMS is lactic acid formation. It is the process where toxic metabolic waste products accumulate in the injury site, causing delayed pain sensation [12]. However, some studies describe other mechanisms of DOMS [13]. The muscle spasm theory describes that DOMS sensation is caused by an ischemic accumulation of metabolic waste products during exercise [14]. The inflammatory theory explains DOMS occurs through muscle responses to exhaustion as oedema formation, inflammatory cell infiltration, and temperature rises. These responses occur due to the degradation of the lipid and protein structure and the accumulation of different chemical mediators in the injury site, which leads to DOMS [15]. Enzyme efflux [16] and connective tissue theory also describe the DOMS mechanism.
DOMS can be identified or diagnosed in different ways. In general, by evaluating or examining the clinical signs and symptoms like 1) inspecting the muscle appearance, swelling, and colure, 2) muscle palpating, and 3) functional testing and pain measurement. These examinations must be held within 1 and 2 days after an unaccustomed eccentric exercise [10]. Several imaging methods have been used to assess the DOMS, including ultrasound, magnetic resonance imaging (MRI), and shear wave electrograph [17]. MRI and conventional ultrasound imaging analyse low to high-grade muscle damage and injury. Chemical and laboratory tests, such as creatine kinase (CK) activity level, are also used to diagnose muscle injury. [10] The proposed mechanism of DOMS needs proper treatment procedures to reduce pain intensity early, improve functional activity, or prevent further injury.
Treatment strategies can be administrated differently, like prophylactically for prevention purposes and conservative management, including Pain medication and Physiotherapy management for curative purposes. As a part of medical management for DOMS, Non-steroid anti-inflammatory (NSAID) drugs are widely used, e.g., diclofenac, naproxen, etc. Which helps reduce pain and inflammatory response [18]. However, in the case of a mild form of muscle injury, NSAIDs do not need to be used because a study suggests that NSAIDs have a negative effect on skeletal muscle regeneration as well as inhibit inflammatory responses [19, 20].In the treatment of DOMS, physiotherapy management is a better option than analgesics or NSAIDs [21]. For this circumstance, physiotherapy management for DOMS is a better option where various types of methods are used, like stretching, cryotherapy, myofascial release (MFR), extracorporeal shockwave therapy (ESWT), acupuncture, and compression [22]. Stretching is a therapeutic technique that promotes muscle extensibility, enhances flexibility, and lengthens tissue [23]. In DOMS, stretching helps to reduce muscle spasms by elongating muscle and increasing circulation on muscle. It is also used as a prophylactic method [24]. As conservative management, Cryotherapy is also used to manage acute pain and muscle injury. The use of cold on the injured side has an analgesic effect and reduces the signs of muscular damage. However, a study suggests a very mild impact on the perpetuation of muscle tenderness or strength deficit [25]. One study also describes the use of cryotherapy to improve soft tissue injury by reducing swelling, circulatory effect, and intravascular pressure [26] Myofascial release (MFR) helps to treat DOMS. This technique acts as a direct, gentle, sustained force for relaxation of the contracted muscle, improvement of venous and lymphatic circulation, and stimulation of stress reflexes [27].MFR also has a crucial role in reducing pain and soreness and improving muscle excitability. Evidence suggests that MFR also has a remarkable effect on muscle flexibility and helps to reduce exercise-induced muscle soreness [28] To reduce pain and inflammation in DOMS, shockwave therapy is another treatment approach. As a part of shockwave therapy-Focused extracorporeal shockwave therapy(fESWT) and radial extracorporeal shockwave therapy (rESWT) are widely used to treat muscle injury including tissue healing and pain reduction [29]. A study suggests that focused extracorporeal shockwave therapy significantly reduces pain intensity [30]. Besides, rESWT helps specifically to reduce musculotendinous pain and muscle triggers. A retrospective analysis describes that rESWT significantly improved in reducing grade 1 and grade 2 acute muscle injury [31]. However, there is no study to see the effectiveness of rESWT on exercise-induced DOMS, and there is also no clear evidence of rESWT compared with other treatment approaches, including MFR and Stretching. So, it is necessary to study the individual effects of rESWT, MFR, and Stretching and evaluate the combined implementation of these treatment approaches.
So, the study aims to evaluate the effectiveness of rESWT, MFR, and stretching on exercise-induced DOMS as separate interventions along with cryotherapy and compare the effectiveness of these three approaches. The study's objectives are as follows: 1) To evaluate each group's sociodemographic status and baseline compatibility. 2) To find the effect of rESWT, MFR, and Stretching with cryotherapy on pain reduction in exercise-induced DOMS for biceps brachii muscle 3) To elicit the within-group differences of rESWT, MFR, and Stretching with cryotherapy to mitigation of pain in (immediate post-test-1),24hr post-test-2, 48hrs post-test 3, and 72 hours (post-test-4) compared to baseline and 4) To find out the effectiveness among groups (of rESWT, MFR, and Stretching with cryotherapy) and observations (pretest to post-test 4, pretest to post-test1, and post-test 1 to post-test 2, post-test 2 to post-test 3) comparison in the mitigation of pain and ROM.
This study has two-tailed hypotheses: Using rESWT, MFR, and Cryotherapy to treat exercise-induced DOMS has different efficiencies in pain reduction and healing. Also, rESWT is more effective than MFR and Cryotherapy in pain remission.