Part II
The anthropometry and biomechanics associated with
squats are the topic of this second part, where I examine different squat
positions and their effects on different parts of the body. Demers et al. 2018,
Gomes et al. 2020 have studied various physical characteristics, such as the
length ratio of the legs and the flexibility of the joints in relation to
squats. In particular, the ratio of the length of the femur and tibia became an
important factor, because in squats, the flexion and extension of the hip and
knee are carried out by the movement of the femur and tibia. A study by Demers
(2018) found that a higher femur-tibial ratio is associated with greater
dorsiflexion and knee flexion muscles, especially in squats with a narrow leg
position. According to MacKea et al. (2012) used 3D kinematic analysis to
investigate possible differences in movement between men and women during
squats. According to the study, men lean somewhat more forward, which gives the
spine movement and depth into a squat. Women, on the other hand, use the knees
and sacrum to achieve the depth of the squat, also using the hip flexion more
strongly. The use of knees was more pronounced in women, and taller women had a
larger knee angle than shorter women. Taller men, on the other hand, emphasized
smaller hip angles. At least the benefit of the study is that men and women use
different movement strategies in squats, in which case it should be taken into
account in both coaching and rehabilitation. The purpose of the study of Kim et
al. (2021) was to investigate the relationships between physical
characteristics and lower limb biomechanics during squat movement. They were
trying to find out whether there are also gender differences in these. They
measured the ratio of femoral to tibial length, mobility of hip and ankle
joints, and relative muscle strength. However, no significant gender difference
was observed in these factors in this study. The biomechanics of the lower
limbs have been shown to correlate more with relative muscle strength and joint
mobility than with the length ratio of the legs.
Another interesting aspect of anthropometry is related
to the length of the femur. Cooke et al. (2019) studied the effects of
hamstring length on the number of repetitions of the squat movement. The result
was that the subjects with the longest femur were able to do significantly
fewer repetitions than the subjects with the shortest femur. The results also
revealed that body mass, fat percentage, and femoral length are all inversely
related to repetitions performed at 70% of 1RM in the back squat. Longer femoral
limbs and longer muscle lengths also seem to be associated with greater muscle
damage (Nogueira et al. 2011) and weakening of muscle function during
contraction (Behrens et al. 2012).
 |
| Photo by Leon Ardho |
The review of Escamilla
et al. (2001) focused on the shear and compression forces of the lower leg and
femur (tibiofemoral), the compression forces of the kneecap and femur
(patellofemoral), and the activity of the extensor and flexor muscles of the
knee. According to this, athletes with healthy knees can be recommended to
squat horizontally (i.e. where the femur goes horizontally) instead of deep
squats, because the risk of injury to the meniscus, cruciate ligaments and
collateral ligaments may increase with deep squats. However, squats do not
compromise the stability of the knee and can even increase stability when
performed correctly. According to the review, squats are found to be an effective
developer of hip, knee and ankle muscles, as it involves moderate to high
activity in the muscles of the front thighs, hamstrings and calves.
A wider squat position is recommended if the goal is
to optimize the development of hip adductors and hip extensors (e.g. gluteal
muscles) (Miyamoto et al. 1999). A narrower squat position is more effective in
targeting the development of the calf muscles (m. gastrocnemius) (Escamilla et
al. 2001). On the other hand, the squat position can also be varied to alter
the forces related to the joints, since the narrow position helps to reduce the
compressive forces (both patellofemoral and tibiofemoral). The wide squat
position causes the smaller knee translation forward, reducing the shear forces
(Escamilla et al. 2001).
Recommended squat technique to minimize risks
|
Gaze |
Backbone |
Depth |
Knee angle |
Feet |
|
Forward or up |
Neutral, straight, lumbar |
Preservation |
115° Knees No |
Neutral Heels on the ground |
Finally, it should be noted that in addition to the
sport-specific squat technique, athletes should also practice various squat
variations for the sake of training variety, preventing overuse injuries, and
ensuring progress. This also applies to other trainees: it is beneficial to
switch up different positions and vary the use of machines and free weights. On
the other hand, it is important to consider the trainee’s anthropometric
characteristics, so that the squat technique can be fine-tuned to their proportions,
making it an optimal and less risky exercise. For example, individuals with a
torso-to-limb ratio shorter than average typically also have relatively longer
femurs. The formula used to calculate the relative length of the femur has been
applied in some studies as follows: (femur length / total body length) x 100%.
The typical relative femur length is 25%, and a larger number indicates that it
will affect the biomechanics of the squat. A safe squat position in this case
would be a narrower/shoulder-width stance with a platform under the heels.
Weightlifting shoes with a raised heel work well too. This helps avoid harmful
compressive and shear forces on the lumbar spine and sacroiliac joint,
alleviates pressure on the straightening of the lumbar lordosis and rounding of
the lower back. The squat position thus remains more upright, with the back in
a neutral position. All of this significantly reduces the risk of a herniated
disc. On the other hand, squat depth can be influenced by a wider foot stance
if the goal is to achieve the deepest squat possible.
Photo: Squat (Photo by Leon Ardho from Pexels:
https://www.pexels.com/photo/photo-of-man-lifting-barbell-1552106/)
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