Movement analysis- Landmine™ step up
By Iris Saar
The hip joint is a complex structure. It is a diarthrodial (ball and socket) joint[i], capable of moving in all three planes. It is responsible not only for carrying our body weight, but also transmits ground forces. Such vertical forces occur first and foremost with ADL’s such as walking, but their magnitude increases with the engagement in impact sports. Repetitive movements such as running requires the hip joint to act as a major stabilizer in addition to the shock absorbance its articulations assists in. Running related injuries among runners are reported at a concerning rate of %35-%45[ii]. The rate and magnitude of those injuries might increase with long distance running (marathons and ultra-marathons, with rising popularity in races, reaching 100 milers’ distances with various terrains- for example, the famous Leadville 100 ultra-marathon race). Some of the most common injuries are trochanteric bursitis, iliotibial band syndrome, snapping hip syndrome and hamstring tear- all related to hip stability, or the relative lack of. Since stability is rarely complete, many strength and conditionings programs try to address and improve it through loaded exercises in an unstable environment.
The two major factors which may challenge (uni and bilaterally) hip stability in an applied exercises program are loading and balance. I have incorporated loading using a “Landmine™”- a weighted steel sleeve barbell, angled and anchored to a base on one end, with the opposite end being pushed through. The Landmine offers a variety of angled movements and enables increased loading due to the anchor. The movements performed are highly functional in nature- for example; the reviewed loaded hip flexion is a key ADL, present virtually in all movements from getting out of bed to walking. Hence, I believe it can be used (in a lighter setting, appropriate setting and intensity) also in rehabilitation programs and with elderly populations as well. The balance was implemented using an open kinetic chain with the Landmine, where the foot can move freely[iii]. Contrary, in more traditional barbell / dumbbell exercises, the exercises are performed through a close kinetic chain- where the lower limbs are grounded and fixed on a firm object[iv]. Here, as detailed below and shown (Figure 2), the athlete steps up and the flexed limb’s stability is challenged due to the open kinetic chain set up. Balance is also achieved through the recruiting of local vs. global muscles[v]
The three key positions (Table 1) demonstrated in this exercise are-
A. Hip (coxal) joint flexion (figure 3): correlation between the load and the angle of flexion. Shown here is an approximately 90⁰ flexion.
B. Hip (coxal) joint extension (figure 4): increased with the suggested progression and visible with spinal extension. Measured here at 51.1⁰ when axis is on the Iliac crest.
C. Knee (Tibiofemoral) joint flexion (figure 3): when parallel to the femur, T/F joint flexion is measured here at 58.6⁰.
Concentric phase- Starting from a step up position on an exercise stool, the athlete is pushing through a 45 lbs. “Landmine™” (figure 1) - a weighted steel sleeve barbell. Stepping up on an exercise stool, she continues to push bilaterally till an approximate 45⁰ shoulder flexion is reached in the sagittal plane.
Eccentric phase- Stepping off the stool into a staggered stance, stabilizing and extending the hip of the loaded limb. Arms are in a resting elbow flexion position.
Progression- increasing ROM by stepping further back while maintaining posture- 2nd toe aligned with knees.
Regression (not shown) - eliminate use of stool, limit ROM, use bilateral Landmine push.
Figure 1: bilateral push through the Landmine and hip extension
Figure 2: open kinetic chain
Figure 3: hip & knee flexion
Figure 4: hip extension