patients.(6) As well, aging and leg strength are related, and both contrib-ute to the age-related changes in me-chanical output during gait.(7) Age-re-lated changes in neuromuscular activity contribute to stiffening of the lower limb and to reduced push off power at fast walking speeds.(8) The neuro-muscular junction may also be compromised, which will affect the ability of a muscle to produce force. The muscle force interaction hinges on structural changes in the muscle, ie., decrease Type II fibers and nerve mus-cle synergy (9), in aging skeletal mus-cles. (10) Age affects the hamstring muscles, lowering both contractile function and motor unit discharge rates. The discharge rates can be spe-cific to a part or a compartment of the muscle.(11) This can lead to increased (25%), co-contractions around the knee joint in the aging compared to young adults and this will affect the swing phase of walking and stair use. (12) Aging also affects the proprioceptive signal which enters the body via the feet, causing dysfunction in the neural pathways, decreasing sensitivity, acuity, and integration of the proprioceptive signal. These signal alterations will causes major changes in postural control, decreasing their effec-tiveness, which will have deleterious consequences for the functional inde-pendence of the aging individual.(13) Aging changes the neuro-muscular environment, which affects how the muscles in the lower limbs contract, or co-contract. These muscle changes will affect the coordination between the foot and the lower leg, changing ankle motion and ankle power. This loss of ankle strength and power has to be compensated by other parts of the lower limbs in order for the normal gait cycle to occur. Knee power increases in order to maintain gait efficiency.(14) But this changes the dynamic foot-shank coordination (15), which further changes gait mechanics, speed, pos-tural balance and can lead to abnormal wear of the joints. The speed and pos-tural chaanges will also selectively af-fect the motor neuronal pools in the lumbar and sacral areas, which will further affect center of body mass, power production and may alter the performance of specific locomotor tasks.(16) Assessing and strengthening foot and lower limb muscles will help and correcting the ankle joint mechan-ics can help to improve the hip abduc-tor muscle strength.(17) PELVIS AND TRUNK If there are muscles in the lower limb that can affect gait, are there pelvic and trunk muscles which can also impact gait? A percentage of people, especially women, develop thoracic kyphosis which affects the mass of the erector spinae and psoas major muscles.(18) The kyphosis weakens the erector spi-nae and decreases stability, changes the center of mass of the body and contrib-utes to pelvic flexion and psoas major atrophy. The psoas major is important ADVANCED CLINICAL NATUROPATHIC MEDICINE Advanced Clinical Naturopathic Medicine engages the reader and evolves their knowledge and understanding from the fundamental Clinical Naturopathic Medicine to a more specialized focus. This new title showcases how transformative and effective naturopathy is and offers insight into the depth of naturopathic practice and its vital role in the healthcare system. With the profession constantly evolving and naturopathy more-often incorporated into specialty practices, this publication is a timely resource. $141.75 Item #0729542654 877-267-3473 annexbookstore.com www.Cndoctor.ca CND_BOOKSTORE_JULAUG21_ASK.indd 1 July/August 2021 Chiropractic and Naturopathic Doctor 21 2021-06-22 9:35 AM
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