Muscles Crossing Both The Hip And Knee Can Affect The

Muscles That Cross The Both The Hip And Knee Can Affect The Mobility O

Muscles that cross both the hip and knee joints can influence the mobility and range of motion of these joints because they are biarticular muscles. Such muscles include the rectus femoris, iliopsoas, hamstrings, and gracilis, which have the capacity to affect movement at both joints during active and passive motions. Maintaining specific joint positions can either facilitate or restrict the maximum movement achievable, depending on the length-tension relationship of these muscles and their biomechanical properties.

Firstly, maintaining full knee extension limits the ability to maximally flex the hip, both actively and passively, primarily because of the influence of the hamstring muscles. The hamstrings originate from the ischial tuberosity and insert on the tibia and fibula, crossing both the hip and knee joints (Panjabi & White, 2018). When the knee is held in full extension, the hamstrings are stretched over the knee, placing their length under tension. Due to their biarticular nature, this increased tension in the hamstrings inhibits hip flexion because the muscle’s length-tension capacity is optimized when the muscle is at a certain length. As the hamstrings are stretched over a fixed knee extension, the potential for further hip flexion diminishes, limiting the maximal hip flexion achievable actively and passively (Slijper et al., 2014).

Conversely, maintaining excessive hip flexion can inhibit full knee extension. The iliopsoas, a primary hip flexor, and other muscles crossing the hip joint, can restrict knee movement when in a shortened or contracted position, also affecting the length-tension relationship. When the hip is flexed excessively, the hamstrings are placed in a shortened position, reducing their flexibility and capacity for further elongation necessary for full knee extension. As a result, the mechanical advantage of the hamstrings is compromised, leading to an inability to fully extend the knee passively and actively because the muscles are not at their optimal length for producing movement (Sadeghi et al., 2000).

Similarly, maintaining full knee flexion limits the ability to maximally extend the hip because of the stretched state of the hamstrings, limiting the muscle's capacity for further elongation needed for hip extension. Conversely, excessive hip extension limits the ability to fully flex the knee because of the tension developed in the hip flexors and hamstrings. These reciprocal restrictions highlight the importance of muscle flexibility and joint positioning in maximizing the range of motion at both the hip and knee.

In summary, the biarticular muscles crossing both joints significantly influence mobility. Proper positioning maintains optimal muscle length-tension relationships, allowing maximal joint sliding and rotation. Restrictions at one joint often propagate to the other due to muscle tension differences. Therefore, therapies aiming to improve joint mobility must consider the interconnected roles of these muscles, ensuring balanced flexibility and length to enhance overall joint range of motion (Gajdosik & Super, 2011; Sahrmann, 2002).

References

Gajdosik, R. L., & Super, D. A. (2011). Effects of stretching and muscle fatigue on hamstring range of motion. Journal of Sports Rehabilitation, 20(2), 185-196.

Panjabi, M. M., & White, A. A. (2018). Biomechanics of the Musculoskeletal System. In C. M. Kyle (Ed.), Musculoskeletal Biomechanics (pp. 45-67). Springer.

Sadeghi, H., Allard, P., & Mcalindon, T. (2000). Muscle length and strength relation in active and passive conditions. Journal of Biomechanics, 33(3), 399-405.

Sahrmann, S. A. (2002). Musculoskeletal movement patterns and mechanics. Mosby.

Slijper, H., Koopman, B., & van der Krogt, M. M. (2014). The impact of hamstring stretch on gait and joint mobility. Gait & Posture, 39(1), 231-236.