The Effect of Aquatic and Land-Based Exercises on Pain Reduction, Muscle Strength and Kinetic/Kinematic Variables in People With Chronic Low Back Pain: A Review Study

* Corresponding Author: Behnaz Maleki, MSc. Address: Department of Pathology and Sport Biomechanics, Faculty of Sport Sciences, Bu-Ali Sina University, Hamedan, Iran. Tel: +98 (918) 0590155 E-Mail: malekinaze@gmail.com 1. Department of Pathology and Sport Biomechanics, Faculty of Sport Sciences, Bu-Ali Sina University, Hamedan, Iran. 2. Department of Sport Pathology and Sport Physiology, Faculty of Sport Sciences, Arak University, Arak, Iran. *Behnaz Maleki1 , Zahra Raisi2


Introduction
ow Back Pain (LBP) is among the most prevalent health problems that affect both genders and all age groups [1]. It is the most significant factor affecting the health and functional ability of the elderly [2]. Among the studies on the LBP prevalence in men and women of all ages, Hoy et al. detected its high-L est prevalence among women aged 40-80 years [4]. In most cases, LBP is caused by poor posture and muscle weakness [7]. Because of the pain caused by disease, these patients suffer from back muscle distortion, decreased spinal function, and eventually physical inactivity and inability to use those muscles [8]. Numerous methods have been suggested to treat and reduce LBP. Aquatic exercise is a wellknown exercise, i.e. used as an effective and safe measure for patients with LBP [21]. Water exercise reduces stress on the joints and the load on the spine [22]. This study aimed to review the effect of Aquatic Exercise (AQE) and Land-based Exercise (LBE) on pain reduction, muscle strength, as well as kinetic and kinematic variables in people with chronic LBP.

Materials and Methods
For the review, we used the related papers published from 2005 to 2019 by searching in PubMed, ScienceDirect, and Google Scholar databases. We applied the following keywords: "Chronic low back pain, kinetic, kinematic, hydrotherapy, aquatic, training, gait, intervention, and physical exercise." Initial search resulted in approximately 2000 articles related to the subject of the present study. After reviewing the title and abstracts of the gathered articles, 110 papers were selected for further review. Finally, by reviewing the full texts of the articles and taking considering factors, such as the effectiveness of therapeutic exercises on people with chronic LBP and the evaluation of walking parameters, 34 papers were selected for the analysis.

Results
Previous studies have revealed that LBP causes motor disorders in other body parts when performing motor tasks. For example, LBP has been reported to decrease the intensity of lower extremity muscle activity during gait [23]. It also reduces ground reaction force and loading rate while walking. This may indicate that these individuals have more significant asymmetry in the kinematics of their lower extremities during walking, compared to their healthy counterparts [25]; in turn, it causes lower extremity injuries [26].
Among the exercises suggested for patients with chronic LBP, a group of exercises are called William flexion exercises. These exercises are essential in the routine treatment of these patients [27]. Another view has suggested that appropriate treatment is selected based on the type of back pain and its cause. In this regard, McKenzie suggests exercises with emphasis on lumbar extensions, given the patient's history and symptoms [28]. Hydrotherapy research results have suggested that performing AQE for 8 weeks, two sessions per week can reduce fatigue in this group; consequently, it improves pain, muscle spasms, and inability to perform daily tasks [31].
Studies have indicated that the lack of kinetic and kinematic coordination in the lumbar region, especially with sudden perturbations, may cause musculoskeletal injury [38]. Postural compensatory strategies may lead to a better understanding of spinal movement patterns; this could help to clarify the relationship between kinetic and kinematic changes in people with chronic LBP. According to Sung et al. the group with chronic LBP demonstrated kinetic stability [38].
Applying AQEs has become increasingly popular for the treatment and improvement of various complications and diseases. Meanwhile, the types of evaluated variables and the conditions of exercise in different studies were different. Sjogren et al. explored the effects of AQEs and LBEs on chronic LBP and concluded that AQEs are more effective than LBEs [9]. Dundar et al. [8] examined the effect of AQEs in patients with LBP. They reported that performing these exercises for two weeks affects the kinematics of the trunk and lower limbs [8].

Conclusion
AQE can significantly change pain, disability, as well as the kinetic and kinematic patterns of gait in patients with chronic LBP. The obtained data revealed that in some cases, these changes might modify the gait pattern and obtain a more optimal pattern. In this regard, AQE was associated with reducing traumatic risk factors. Furthermore, it could significantly reduce the risk of injuries caused by back pain. However, limited studies have addressed the ineffectiveness of these exercises. Thus, despite the previous study results, further studies are required to assess more diverse conditions using a larger sample size.