Matemáticas y etnomatemáticas en la Capoeira

Compression as a treatment for human disease dates back to Hippocrates 450 BC, utilised primarily in the treatment of venous disorders and leg ulcers (Gladfelter 2007). This progressed to body wrapping in the treatment of soft tissue injury to minimise swelling and edema and to minimise scar tissue formation following burns (Gladfelter 2007). The introduction of synthetic fabrics in 1983, including nylon, in addition to the progressive development of women’s undergarments, saw the increase in the number of surgeons using 58

commercially available undergarments in postoperative care of patients (Gladfelter 2007). Today, compression garments are designed to cover a small section such as the part of a limb or to cover whole body segments such as items of clothing, e.g. pants and tops.

Compression garments are constructed from an elastic material, with a graduated compression design most commonly adopted (Linnitt and Davies 2007a). Compression is measured in millimetres of mercury (mmHg), which refers to the pressure exerted at the ankle by the garment at rest (100% of the compression is at the ankle, this then reduces to 40% at the thigh (Figure 2.3).

Figure 2.2 Graduated Compression Garments

Source: (Linnitt and Davies 2007b)

There are differing classifications of compression available, including the German RAL GZ387 (for Hohenstein Institute tested hosiery), French Standard ASQUAL and British Standard BS 6612 (Figure 2.4) (Bianchi and Todd 2000; Clark and Krimmel 2006; Linnitt and Davies 2007a). Sports compression garments typically fall into the lower of the three

classes, class I, due to the lower level of compression exerted, with medical garments typically being allocated class II and III.

Figure 2.3 Classification of compression

Source: Linnitt and Davies 2007

As a broad principle, the level of compression is directly proportional to the tension with which the compression device is applied, and inversely related to the size of the limb according to Laplace’s Law (Clark and Krimmel 2006). The tension exerted by a compression garment is related to both the type of yarn used in its construction, and the knitting technique used to produce the fabric. The fabric selected to make compression garments is produced by knitting two types of yarn together. Inlay yarn provides the compression and body yarn delivers the thickness and stiffness of the knitted fabric (Figure 2.5) (Clark and Krimmel 2006).

A B

Figure 2.4: The arrangement of inlay and body yarn in flat knit (A) and circular knit fabric (B).

Source: Clark and Krimmel 2006.

Both types of yarn are produced by wrapping polyamide or cotton around a stretchable core such as latex or elastane (Lycra) (Figure 2.6). The wrapping can be adjusted to vary the stretchability and power of the yarn. The stretchability is a measure of how far the yarn can be elongated, and the power is a measure of how easily it stretches. High power yarn is less easy to stretch and is stiffer than its low power counterpart, and thus applies greater compression (Figure 2.6). The thickness, texture and appearance of the knitted fabric can also be changed by adapting the wrapping of the yarn. Higher levels of compression are achieved by increasing the thickness of the elastic core of the inlay yarn, although adjustments may also be made to the body yarn (Clark and Krimmel 2006).

Figure 2.5: The fibres that make up body and inlay yarn. The wrapping of the outer fibre around the stretchable core can be adjusted to vary the stretchability and power of the yarn. Looase wrapping (a) means the yarn has more stretch and less power than a yarn in which the fibres are tightly wrapped (b). Source: Clark and Krimmel 2006.

Proper fit is essential in the optimisation of compression garment use (Kraemer, Bush et al. 1996). With high compression or with compression used to treat extreme soft tissue injury, compression may augment feelings of discomfort during the period the garment is used

despite the positive results because of mechanical blocking of edema (Kraemer, Bush et al. 1996; Kraemer, Bush et al. 2001a; Kraemer, Bush et al. 2001b; Silver, Fortenbaugh et al. 2009). Proper fit (e.g. seams not problematic or constrictive) and feel (e.g. garment material) are important mediators of garment efficacy, particularly when worn for long periods of time. Adequate compression and proper construction create the potential for optimal skin contact, which is vital for proprioception (Kraemer, Flanagan et al. 2010). It is also an important consideration that garment movement is minimal and stays in contact with the skin to prevent air bubbles breaking the linkage with the skin, and thus the stimulation of skin receptors (Kraemer, Flanagan et al. 2010).

Today, commercially available sports compression garments are worn by individuals ranging from recreational exercisers to elite athletes in a bid to accelerate post exercise recovery and to gain an edge over their opponent. Thirty one studies have investigated the effect of wearing compression garments on indicators of performance and recovery from exercise, with sixteen focused specifically on recovery from exercise (Born, Sperlich et al. 2013). Yet only three studies have explored compression garment use exclusively during the recovery period, with elite athletes in actual sporting scenarios (Gill, Beaven et al. 2006; Montgomery, Pyne et al. 2008a; Montgomery, Pyne et al. 2008b). Compression garments are widely used by team sport athletes in training and competition scenarios to aid their recovery. It is clear that despite the current body of research on compression garments, little is known regarding their efficacy for these elite athletes in actual training and competition scenarios.