Effects of Core Strengthening on Cardiovascular Fitness, Flexibility and Strength on Patients with Low Back Pain

Background: Back pain is a common complaint for people of all ages. Chronic back pain sufferers have been estimated to constitute ¼ of the population. People who sit for prolonged periods of time are predisposed to have low back pain problem frequently.

Methodology: In this study, 30 patients were selected according to inclusion and exclusion criteria and were assigned into two groups: experimental group and control group. The experimental group was given core strengthening exercises and control group was given conventional exercises. The intervention was followed daily for 4 weeks. Prior to the exercise and after every week VO_2max, flexibility and strength were evaluated as outcome measure.

Results: Both the groups had significant effect on VO_2max, flexibility and strength at the end of 4^th week (p<0.05). Cardiovascular fitness, flexibility and strength improved more in the experimental group.

Conclusion: Core strengthening exercise improves muscle imbalances, posture and enhances cardiovascular fitness, flexibility and strength in patients with low back pain.

Low back pain; Core strengthening; Flexibility; Strength

Low back pain is a leading cause of disability, contributing to decreased cardiovascular fitness, muscular strength, flexibility, bone density, and disk nutrition; increased spinal segment stiffness and depression which are also associated with inactivity. It is the most common cause of disability in people younger than 45 years of age. Despite a decrease in symptoms, these patients have anatomic and functional changes that increase their chance of reinjury [1]. Low back pain problem are usually linked to two causes: first lifestyle, which indicates stress, lack of exercise and poor posture and second physical injury. Stress can be precursor to low back pain by upsetting the nervous system and causing muscles to go into spasm. Bending lifting and twisting movements can lead to muscle strain and ligament sprain, most commonly associated with acute low back pain [2,3]. Many people have back pain whether its upper back pain or lower back pain and this may be partly caused by weak abdominal muscles. Weak abdominal muscles are correlated with a high incidence of back injury. The upper and lower back is composed of individual segments of the spinal cord, if it is not kept in the proper position than it can cause undue strain on ligaments, tendons, and muscles [4]. Decreased muscle flexibility, trunk strength and poor muscle endurance have been reported to be associated with back pain issues [3,5].

Prevention of chronic or recurring back pain can be done by learning and practicing good postural habits, increasing strength and endurance of the muscles that support the spine. Current medical literature suggests that exercise appears to exert a neutral effect or may even slightly reduce the risk of future back injuries. The benefits of exercise are profound and include improved cardiovascular fitness, muscle strength, flexibility, and endurance [1]. The goals of these exercises is to improve impaired back function, decrease back pain symptoms and minimize the disability by diminishing excessive fears and concerns about back pain [6].

Core strengthening has a theoretical basis in treatment and prevention of various musculoskeletal conditions. The “core” has been described as a box with the abdominals in the front, paraspinals and gluteals in the back, the diaphragm as the roof, and the pelvic floor and hip girdle musculature as the bottom. Core serves as a muscular corset that works as a unit to stabilize the body and spine [7]. It also describes the training of muscle around the lumbar spine and the abdomen and functions essentially to maintain spinal stability and pelvic balance [8]. Weakness in any of the core muscles can affect spinal stability and leave the lower back vulnerable to injury. Core stabilization exercise through effective abdominal training helps to increase the strength, stability, balance and stamina. So the training of trunk or spinal stabilizers is therefore supposed to helpful in improving the endurance of trunk extensors or mobilizers and preventing development of backaches in future [9].

Cardiovascular training can result in improved blood flow to muscles, enhanced VO_2max (maximal oxygen consumption during exercise), lower heart rate for a given level of exertion. Flexibility is defined as the ability to move a single joint or series of joints through an unrestricted pain free range of motion. Muscles prone to tightness in LBP patients include erector spinae, quadratouslumborum etc., therefore the goal of a rehabilitation program for LBP is to correct muscle weakness and imbalances with strengthening exercises. Strength of core muscles are found to be affected in the patients with LBP and most commonly multifidi muscles are found to be atrophied [1]. Therefore, core strengthening has been promoted as a preventive regimen, and a rehabilitation program for enhancing various lumbar spine and musculoskeletal injuries.

Participant�s

Experimental protocol

The data was analysed using SPSS 17.0 for windows. Independent sample t-test was performed to see any difference between the groups. One way analysis of variance (ANOVA) post-hoc Tukey test were used to determine if there was any difference in 0 day, 1^st week, 2^nd week, 3^rd week and 4^th week. The significance level was set at p<0.05.

Independent sample t-test between the groups showed significant difference in flexibility, strength and VO_2max at 4^th week (Table 1). The result of one way analysis of variance (ANOVA) within the experimental group (Group-A) showed significant difference. (Table 2) One way analysis of variance (ANOVA) within the control group (Group-B) showed significant difference in all the variables viz. flexibility, strength and VO_2max (Table 3 and Graphs 1-5).

The study aimed to find the effect of core strengthening on cardiovascular fitness, flexibility and strength on patients with low back pain. The benefits of core strengthening are profound and it also improves cardiovascular fitness, muscular strength, flexibility and endurance. Studies have shown that patients with chronic LBP have reduced strength and greater atrophy of the back muscles in comparison with healthy control patients. Thus the study was designed to find the effect of core strengthening on cardiovascular fitness, strength and flexibility on patients with low back pain. The data analysis revealed that both the groups showed significant improvement in VO_2max, flexibility and strength (p<0.05) within the group.

According to (Susan C. Soroskys et al.) [1] “Cardiovascular training can enhance metabolism of free fatty acid thus reduces body fat, increases insulin sensitivity and improves blood flow to muscles, the involuntary cardiac muscles present in the heart facilitate the pumping of blood through the body. With regular exercise cardiac output increases, thus VO_2max increases. Heart rate lowers for a given level of exertion, and reduces blood lactate accumulation at a given sub-maximal level of exertion”. (Stanley P. Brown) [14] Stated that with strengthening exercise, there is an immediate need to meet the increased demand of oxygen with an adequate supply. To do this, there is an integrated response from the cardiovascular and pulmonary systems. The heart rate and the strength of the cardiac contractions increase which produces a greater cardiac stroke volume. These factors result in an increase in the delivery of blood to the working muscles and this constitute the central factor for the increase in oxygen consumption that occurs with exercise. Both cardiac output and oxygen consumption increases step-by-step. The increase in oxygen consumption with exercise results from an increase in pulmonary ventilation. Pulmonary ventilation is the bulk of air into and out of the lungs. After the initiation of exercise, both the rate and depth of breathing increases, this results in an increase in pulmonary ventilation. As the intensity of exercise increases during activity more oxygen is extracted from the blood as the blood passes through the capillaries of the working muscles and more air is passed in and out of the lungs. The increased rate at which the lungs are ventilated allows more oxygen to be delivered to the working muscles.

Core strengthening exercise enhances flexibility of patients having low back pain. The exercises aim to correct muscle tightness, and allow the patient to assume a neutral position so that strength can be developed to help maintain correct neutral positioning during both static and dynamic conditions. Due to eccentric muscle contraction there is an overall increase in muscle length. The core muscles are the voluntary skeletal muscles and each individual muscle cell is called muscle fiber. During core strengthening exercises each muscle fiber extends to the full length of the muscle. According to (Susan C. Soroskys et al.) [1] “Flexion during the exercises may reduce facet joint compressive forces and provide stretch to the lumbar muscles, ligaments, and myofascial structures.” (Gross and Worrell) [15] Emphasized on the importance of flexibility enhancement and reported that enhanced flexibility has a greater effect on the range of motion and decreases the risk of musculoskeletal injuries.

Core strengthening exercises enhanced the muscular strength on the patients having low back pain. Strength of core muscles is found to be affected in the patients with LBP. Studies have shown that patients with chronic LBP have decreased strength and greater atrophy of the back muscles and most commonly multifidi muscles are found to be atrophied. According to (Faigenbaum AD) [16] “Strength training has been shown to have a beneficial effect on several health indices, such as cardiovascular fitness, body composition, bone mineral density, blood lipid profiles, and mental health”. According to (Susan C. Soroskys et al.) [1] “The goal of a core strengthening program for low back pain is to correct muscle weaknesses and imbalances with strengthening exercises. Strength training has been used as a successful strategy to reduce LBP and improve function.” “The strength training focuses on the abdominal and erector spine muscles which has an influence on biomechanical functions and stability of the spine and pelvis.” Resistance exercises stress the bodyâÂ?Â?s musculoskeletal system, which enlarges muscle fiber and improves neural control of muscle function which results in greater muscular strength. Strength training increases the size and number of myofibrils, resulting in larger individual muscle fibers. McGraw stated that “Core exercises increases the muscle mass, strength of tendons, ligaments, and bone. It increases utilization of motor units during muscle contractions, thus increases the size and strength of fast-twitch muscle fibers from a high-resistance program and size of slow-twitch muscle fibers from a high-repetition program. It also increases blood supply to muscles (from a high-repetition program) and improved blood vessel health. It improves the coordination of motor units and increases the storage of fuel in muscles and also enhances the muscle endurance. According to (Janet Hopson et al.) “The strength of a muscle contraction depends upon the intensity of the nervous system stimulus, the number and size of motor units activated, and the types of muscle fibers that are stimulated.” When we start a resistance-training program, there is a gain in muscular strength before any increase in muscle size. This is because internal physiological adaptations to training take place before muscle enlargement. The strength of a muscular contraction depends mainly on effective recruitment of the motor units needed for the contraction. The better the body gets recruited the stronger the muscles will be. In the first few weeks of a resistance-training program, most of the adaptation involves an increased ability to recruit motor units, which causes more muscle fibers to contract. In response to resistance training the neural activation improves and as a result to this the amount of actin and myosin within the muscle fibers increases. This leads to an increase in the size or cross-sectional area of the protein filaments and the size of slow- and fast-twitch muscles, thus greater increase in strength will result from hypertrophic changes in fast-twitch muscle fibers.

Core strengthening exercise has a significant result on flexibility on patients having low back pain. Muscles prone to tightness in LBP patients include erector spinae, quadratouslumborum etc., therefore the goal of a rehabilitation program for LBP is to correct muscle weakness and imbalances with strengthening exercises. The exercises aim to correct muscle tightness, and allow the patient to assume a neutral position so that strength can be developed to help maintain correct neutral positioning during both static and dynamic conditions. Additionally, it helps to improve posture and can reduce associated back pains and further injuries, improves muscle coordination and reduces muscle soreness [1]. The core muscles are the voluntary skeletal muscles and each individual muscle cell is called muscle fiber. During core strengthening exercises each muscle fibre extends to the full length of the muscle. Due to eccentric muscle contraction there is an overall increase in muscle length [2]. According to Susan C. Soroskys “Flexion during the exercises may reduce facet joint compressive forces and provide stretch to the lumbar muscles, ligaments, and myofascial structures.” Gross and Worrell [16] emphasized on the importance of flexibility enhancement and reported that enhanced flexibility has a greater effect on the range of motion and decreases the risk of musculoskeletal injuries.

Core strengthening exercise improves muscle imbalances, posture and enhances cardiovascular fitness, flexibility and strength in patients with low back pain.

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