FROM HIPS TO CLIPS: THE IMPORTANCE OF ALIGNMENT FOR CYCLISTS

80–90% of the general population presents with the pelvis, spine, or both out of alignment. Cyclists are no exception, making them vulnerable to suffering needless pain – the most common problems experienced are shoulder, neck, back, hip, and knee pain. It also makes them prone to injury while affecting their style and ability to realize their full potential. They can easily learn to do an assessment on their own or with the help of a friend to establish whether they are out of alignment and in which way. If so, there are some simple techniques that may allow them to correct or, at least, decrease the degree of malalignment present until they can see their therapist.

Fig 1

Fig 2

Fig 3

THE PROBLEM OF BEING OUT OF ALIGNMENT

As described in the blog “Overview of Body Alignment Problems”, the right and left hip bone and the sacrum wedged between them move in a figure-of-eight pattern during our normal walking cycle (Figs. 1, 2). For various reasons, these bones can get stuck out of place relative each other. Both an “upslip” (Fig. 3) and a “rotational malalignment” (Fig. 4) are characterized by changes in body biomechanics from head to toe. The pelvis tilts upward to one side, with formation of compensatory curves of the spine and one shoulder ending up lower than the other (Figs. 5, 4). In addition, there results a side-to-side difference in right versus left:

Fig 4

Fig 5

Fig 6

  • leg length (Fig. 6)
  • weight-bearing; most often, the right leg turns outward and the foot rolls inward or “pronates”, the left leg turns inward and the foot rolls outward or “supinates” (Figs. 7A,B, 8, 9, 10Bi,ii) – the wear of the soles of the shoes and collapse of the heel cups eventually reflect this shift (Fig. 11)
  • strength and tension in pairs of muscles; one appears weak while the one on the other side proves to be strong; one muscle is tensed-up, its partner relaxed (Fig. 12)
  • range of motion possible in any one direction on comparing pairs of joints (Fig. 13)

Fig 7A

Fig 7B

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Fig 9

Fig 10

The tendency to right pronation and left supination results in abnormal stresses on the joints and soft tissue structures (ligaments, tendons, muscles), putting them at risk of becoming tender or outright painful (Fig. 10Bi,ii). For example, pronation lengthens the distance between the pelvis and foot on the inside, supination on the outside, of the leg, creating typical trouble spots (Figs. 9: L, 14: A-F).

Fig 11

HOW PELVIC MALALIGNMENT CAN AFFECT CYCLISTS

ASYMMETRY OF PEDALLING FORCE AND FORM

 In order to generate an equal amount of force on both sides, the legs should move symmetrically and in a relatively straight line, forward and backward, with the knees the same distance out from the crossbar. However, the cyclist who presents with malalignment may be aware of an asymmetry of both strength and form in that:

  •   One side feels weaker in terms of the amount of power the leg can generate when pushing down on the pedal and tends to tire out more easily; set-ups like the Peloton bike make the side-to-side difference in force readily detectable
  • The legs appear to move differently, with movement generally not being as smooth, possibly even awkward, on the weak side
DIFFERENCE IN LEG STRENGTH WITH MALALIGNMENT

Several studies have attributed side-to-side differences in strength to a malalignment-related leg length difference. On the side of the apparent short leg, they have shown:

  • Up to a 5% decrease in the power generated compared to the “long” leg
  • A loss of pedal-stroke efficiency, with the round and smooth “electronic motor” type effect being replaced by a “piston-like” action

Fig 12

Fig 13

Fig 14

Only realignment was felt to improve matters, with the cyclists:
  • regaining a smoother, more rounded stroke on the previously “short” side that was more in keeping with that on the opposite side;
  • being able to ride for a longer period of time at maximum output; and
  • showing a continuing improvement on repeat studies over time, which was thought to be indicative of the body’s ongoing adaptation to its new, now aligned, position.
In someone with an upslip or a rotational malalignment, the right leg is more likely to feel weaker than the left (e.g., on doing a 1-legged squat). Given the large percentage—around 80%—presenting with a right hipbone stuck rotated forward, the right leg is more often the shorter leg in the sitting position (Fig. 6). Other factors that can affect efficiency and the power generated when malalignment is present include the side-to-side differences in style, joint ranges of motion, and muscle tension and strength.

CHANGE IN STYLE: THE KNEES END UP A DIFFERENT DISTANCE AWAY FROM THE CROSSBAR

With an upslip or rotational malalignment, the right knee typically ends up coming closer to the midline—compared to what happens on the left side—as the right foot reaches the lowest point on pushing down on the pedal (Fig. 15A). This inward movement of the knee reflects the tendency of the right foot to pronate and a secondary buckling inward of the right thigh/knee as the leg progressively straightens and the force bearing down on the pedal increases (Figs. 8, 9: R, 10Bi). As the right pedal moves upward and the hip and knee bend on that side, the right knee very obviously moves away from the crossbar. This movement reflects the fact that the malalignment results in an increased ability of the right thigh to rotate outward and the knee to drop down (Figs. 13, 15B).

Seen from the front, the right knee appears to be moving in a circular fashion: inward and down, then upward and out. In contrast, the left knee moves more or less straight up/down and forward/backward along one plane while maintaining a consistently even distance from the bar. The overall movement of the left leg also appears to be smoother in comparison to the right one.

Fig 15A

Fig 15B

ATTEMPTING CORRECTION BY ADJUSTING THE TOE CLIPS

The cyclist may try to improve matters by adding adjustable toe clips, in the hope of stabilizing the feet and counteracting any tendency toward right foot pronation and left supination when pushing down on the pedal. These attempts may involve the following:

ADJUSTING THE RIGHT TOE CLIP TO COUNTER FOOT PRONATION / LEG OUTWARD ROTATION
This can be achieved by turning the toe clip inward – toward or even across midline – and fixing it in this new position, a technique also used by skiers (Fig. 16B: right). The rational is that the right foot, instead of pointing outward and pronating—as is usually the case with malalignment—now ends up pointing more or less straight ahead on reaching the lowest point when pushing down on the pedal. Fixing the foot in this position might be expected to improve the mechanical advantage of the right leg and its ability to generate a force by:

  • Reorienting the right leg muscles closer to their normal position, so that they are able to work more in the line of progression
  • Increasing right ankle stability by decreasing the tendency to pronation

Unfortunately, the right leg really has to be coerced into this straighter position because, as long as the malalignment and tendency to pronate are present, there will be abnormal forces  impelling this leg and foot to turn outward (Fig. 7A,B). If the toe clip now restricts this drift to outward rotation as the knee straightens and the foot pushes down harder on the pedal, the rider may experience increased pressure and pain:

  • On the outer border of the right foot, because its usual movement (outward with the leg) still occurs within the shoe but is now blocked by the readjusted toe clip (Fig. 16B).
  • Around the right knee, given that the toe clip now restricts the ability of the foot to roll inward (pronate), thereby limiting the normal movement that the lower part of the leg usually undergoes relative to the thigh bone and increasing the stress on the knee joint (Figs. 9: R, 10Bi)

Fig 16

ADJUSTING THE LEFT TOE CLIP TO COUNTER FOOT SUPINATION / LEG INWARD ROTATION

  • On the left side, the malalignment results in an increased tendency for the leg/foot to point inward, secondary straightening of the knee, and supination of the foot at end-of-range on pushing down on the pedal. The cyclist may fix the toe clip on this side so it is angled outward a bit, away from midline, to prevent this drift to left inward rotation and supination. However, he or she may come to feel:
    The toe clip now pressing against the inside aspect of the left foot (especially in the region of the forefoot and big toe; Fig. 16B: left)
  • Discomfort from the further disruption of the normal biomechanics of movement between the thigh bone and shinbone that occurs at the knee joint

The cyclist may also try the addition of an orthotic inside the shoe, modified to counteract any obvious tendency to pronation or supination. However, the only long-term solution is realignment followed by reassessment to see if there are any residual problems at the foot level and whether orthotics might still be of help.