The lower crossed syndrome
Have you heard of this syndrome before? Even if you’ve never heard of it, you probably see it every day without realizing that many of the players on your team or in your clinic develop this postural disorder. In this post, we will define what this syndrome is, why it occurs, what the risks are, and how it is related to our greatest enemy, the hamstring injury.
Image 1. Anterior pelvic tilt (Neumann, 2010)
More common than we think in football players
Image 2. Rating scale: 5, ideal posture; 4, minor deviation; 3, significant deviation; 2, marked deviation; 1, severe deviation. (Kritz & Cronin, 2008)
Image 2 presents a study from 2008 by Kritz & Cronin, which demonstrated a tendency towards increased lumbar lordosis in athletes engaged in high-intensity running sports, such as football.
The study, involving 98 athletes, found that 33% of them exhibited marked or severe lumbar deviation during a static posture analysis. Authors like Das et al. (2017) have linked this type of postural imbalance to low back pain, while others, such as Mendiguchia et al. (2024),
have associated an increase in anterior pelvic tilt with greater elongation and strain in the hamstring muscle complex, leading to a higher risk of injury.
Football involves multiple explosive hip flexion movements, such as shooting the ball or passing, as well as short-duration, high-intensity actions like accelerations, decelerations, jumps, or changes of direction. These movements primarily stimulate the hip flexor and knee extensor muscles, leading to increased tension and overactivation of these muscle groups.
When one muscle contracts, the opposite or antagonist muscle relaxes. This is known as reciprocal inhibition. Excessively tight hip flexors will cause reciprocal inhibition of the gluteus maximus, the primary hip extensor (Buckthorpe, et al., 2019). This muscle activation pattern may cause excessive anterior pelvic tilt and, consequently, increase lumbar lordosis. In turn, the increase in lumbar lordosis will cause shortening and stiffness of the lower back muscles and reciprocal inhibition of the abdominal muscles (Image 3). Moreover, when the hip flexors become overactive, they start to take over functions that the abdominal muscles should perform. Again, this weakens the abdominal muscles and leads to the weakening and lengthening of the gluteus maximus due to their agonist-antagonist relationship (Das et al.,2017). Weakness in the gluteus maximus can lead to compensatory actions by secondary hip extensor muscles, such as the hamstrings and hip adductors, clinically known as “synergistic dominance” (Buckthorpe et al., 2019).
Image 3. Lower crossed syndrome (Source: www.erikdalton.com)
How does this syndrome impact maximal speed running?
During maximum-speed running, athletes who present this motor pattern may increase hip and rear leg extension to compensate for the lower activation of the gluteus maximus (Image 4, left). Increasing hip extension during the final stance phase allows the athlete to apply force over a longer time, resulting in a greater impulse (Kritz & Cronin, 2008). Although this may seem positive, it’s actually an ineffective force production strategy used to compensate for the lack of force during the first half of the stance phase, where the peak of ground reaction forces should occur (Bramah et al., 2023). Excessive hip extension lengthens the stance phase and reduces the flight time and the time available to reposition the lower limb for the next foot contact, increasing the speed of the leg change and, consequently, the strain produced on the hamstrings (Bramah et al., 2023). Hip hyperextension may also cause excessive anterior pelvic tilt, which increases stress on the proximal hamstring region during high-intensity running (Mendiguchia et al., 2021).
Image 4. Trailing leg extension (Bramah, et al., 2023)
Several authors, such as Schuermans et al. (2017), have shown how the increased activity of the hip flexors during sprinting increases the strain on the biceps femoris of the contralateral leg. This author also states that the activity of the abdominopelvic muscles, especially the gluteus maximus and abdominal obliques, reduces strain in the proximal region of this muscle. A proper balance of the lumbopelvic muscles, especially the relationship between iliopsoas-erector spinae and abdominal-gluteal muscles, is key to reducing strain on the biceps femoris (Mendiguchia et al., 2021).
This relationship once again highlights the importance of lumbopelvic control during maximum-intensity running. The increase in anterior pelvic tilt will cause a significant elongation of the hamstring muscles (Mendiguchia et al., 2024), which during high-intensity running increases the risk of suffering hamstring injuries (Mendiguchia et al., 2021).
Now that we understand the implications of this inefficient movement pattern, my next question is: How can we assess it and improve it?
We will address these questions in upcoming posts.
See you soon!