What is LAR and FAR? Part 1

Hello this is Fukuma from LEOMO. After having explained DSS in a previous blog, I would like to follow up with a two-part explanation of Leg Angular Range (LAR) and Foot Angular Range (FAR). Both LAR and FAR are two of LEOMO’s Motion Performance Indicators (MPIs). As you may have already figured out from their names, LAR and FAR is the Angular Range measured by the sensors to the thighs and feet.

Strictly speaking, pedaling is a complex, repetitive motion involving multiple muscle groups working together. To simplify this motion let’s take a closer look at just the movement of the thighs and feet.

Pedaling is not much more than an alternation between an up and down movement of the thighs, and the alternation of the feet between heel-up and heel-down as they rotate around the BB, although the latter is more complex than the former.

The thighs and feet generally reach their highest angle before the top of the pedal stroke and their lowest angle before the bottom of the pedal stroke. This may differ from person to person and should be noted that the thigh and feet may not always be entirely in sync. However, the basic pattern of thigh-up and thigh-down, as well as heel-up and heel-down is a necessary component of the pedaling motion and is the same for everyone.

Pedaling is the repetition of this movement and LAR and FAR is the angular range of the movements of the thighs and feet. In other words, LAR is the difference between the angles of the thigh at its highest and its lowest point in relation to a level surface. Similarly, FAR is the difference between the angles of the sole at its highest and lowest point.

The meaning of LAR and FAR

Why are LAR and FAR important in cycling? Generally speaking, the body’s range of motion is impacted by a variety of factors including:

  • Position (geometry)
  • Joint flexibility

In terms of geometry, the act of pedaling is performed by the lower body while the upper body and core stabilize the position. The pelvis, femur, shin, and foot work together with the hip, knee, and ankle joints to produce the rotational movement of the pedals.

Even with the saddle and pedals fixed there are still many degrees of freedom in motion making it, geometrically speaking, impossible to limit body movement. However, since humans aren’t capable of bending their knees in the opposite direction, and the range of the ankles is smaller than that of the hip joints, the movement is instead limited by the flexibility of the joints, which, in turn, determines the range. LAR and FAR are the numerical notations of this range, making it possible to objectively measure. With the TYPE-R we can start to look at movements that previously would have been hard to identify such as the thigh not moving up, the hip joint being blocked, or the ankling movement being too large. LAR and FAR allow us to measure the movement and compare the two, which is important in analyzing motion and identifying each cyclist’s individual characteristics.

In the next article we will describe practical applications for LAR and FAR.

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