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Xsens DOT: Sensor placement

Xsens DOT can produce extremely accurate measurements, including orientation data within 1-degree accuracy (Xsens DOT User Manual, 2020). However, when placed on a human body, other factors such as soft tissue artefacts can introduce errors to your measurement, thereby skewing your results. In order to limit the amount of error, it is recommended placing the sensors in spots where the skin is less likely to move and wobble. Not only is this effective because less motion translates into more reliable data, but also, a smart sensor placement might significantly increase comfort for the user wearing the sensors.

The underlying concept is to place the sensor where there is either less muscle or soft tissue and the sensor has a flat surface to adhere onto. However, the final choice is left to the programmer/developer who can choose how to align the sensor and where to place it.

The pictures below depict Xsens DOT being attached on the outer surface of the strap using Velcro patches (not included in the Xsens DOT starter kit). Note that these pictures are taken only for demonstration purpose and you should always place the sensor inside the pocket and/or wrapped inside the strap to ensure better adhesion and less skin artefacts. Another viable option is to place the sensor in direct contact with the skin and then attach tape to firmly secure it in place. Different types of tape can serve this purpose, however, stretchy tape, such as Kinesio Tape, anecdotally seems to show better performance due to being more flexible, as well as, being more comfortable. 

Below you can find the content and specs of the Xsens DOT Strap Set:

  • 1 Long Strap: 128 cm x 10 cm (50.4” x 4 “) - pocket at 6 cm from the end
  • 2 Medium Straps: 55 cm x 5 cm (21.65” x 2”)  - pocket 4 cm from the end
  • 2 Short Straps: 29 cm x 5 cm (11.4” x 2”) - pocket 3 cm from the end

The material used is called Fabrifoam® X-treme™ and you can download a flyer here.

Finally, items belonging to the MVN Link or Awinda hardware are also proposed as alternative options to secure Xsens DOT on the body. They are not included in the Xsens DOT Starter Kit but they can be purchased separately from the links below should you be interested.

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Sensor placement in the strap. Keep the sensor horizontally (if possible) to prevent movement

Sensor placement using tape (demonstration only). Make sure the entire sensor is covered by the tape.

Head

Anywhere around the circumference of the head, at the forehead height will work. We recommend on one of the sides.

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Head sensor: Place the sensor on one of the sides

Head sensor: the sensor can also be placed in a pocket inside the head band

 

Upper Back / Trunk

If placing 2 sensors, one on each shoulder blade is recommended. If placing only one sensor, place one in the middle, roughly on the T12 vertebra. Alternatively, it is also possible to place one sensor on the sternum, on the Xiphoid process, or above the chest as shown in the picture below

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2-sensor configuration: place them on the shoulder blades using Velcro patches or tape

1-sensor configuration: place the sensor on the sternum using Velcro patches or tape. The spot slightly below the neck is recommended.

 

Upper Arm

On the side of the upper arm, roughly in the middle of the length of the limb, and between the biceps and triceps muscles

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Upper arm placement: place the sensor roughly between the biceps and triceps muscles, on the outer side of the arm

 

Lower arm / forearm

A few centimetres on top and above the wrists. Make sure that the sensors is far enough from the hand to allow full wrist extension without contact. It is recommended using the short version of the strap for the forearm.

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Forearm: a few centimetres above the wrist are enough to ensure good contact and little motion

 

Hands

On top of the hands, roughly in the middle.

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Hand sensor: place the sensor at the centre of the back of the hand. Glove, straps or tape are all valid options

 

Pelvis

On the sacrum

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Pelvis: place the sensor on the sacrum. Use the strap or tape the sensor directly to the skin

 

Upper leg

A few centimetres above mid-thigh, on the outer side of the leg. It is recommended placing the sensor on the IT band, between the quadriceps and hamstrings muscles.

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Upper leg: Both long thick or thin straps are possible. Make sure the end of the strap does not fall between the legs to avoid loosening of the strap during the recording

 

Lower leg

A few centimetres below the knee, slightly medially (internally) placed. Look for the flat spot on the bone. Tip: Facing your subject, palpate the front of the tibia, slightly below the knee, and then move a few centimetres inward.

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Lower Leg: it is recommended placing the sensors medially to lessen motion. However, in case of running activities, where it might be possible to hit the sensor, it is ok to place the sensor outwards (laterally)

 

Foot

Roughly in the middle of the foot. Make sure to leave enough room on either side so that: toe and ankle motion does not influence the sensor.

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Foot: the sensor can be placed on top of the shoe or directly on the foot. Additional tape on the shoe/foot can be a good idea to better secure the sensor during high impact activities such as running or sprinting

 

 

 

 

 

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