# Sport Innovation/Recovery Techniques in Team Sports/Introduction

Maximal repetitive exercise, such as the forms experienced in elite team sports, can often lead to a fatiguing of the musculoskeletal, nervous and metabolic systems, as well as the potential production of delayed onset of muscle soreness (DOMS) (Allen, Dumont & MacIntyre, 2004; Ingram, Dawson, Goodman, Wallman & Beilby, 2009). In addition it is common for muscle shortening, increased passive stiffness, swelling, decreases in strength and power, as well as localised soreness and disturbed proprioception to occur after strenuous exercise (Proske & Morgan, 2011). This fatigue may subsequently lead to decreases in performance (Ingram, et al, 2009). However it is difficult to directly determine the extent of muscle damage which has occurred due to invasive nature of the direct testing methods (i.e. muscle biopsies and magnetic resonance imagery (MRI) (Clarkson & Hubal, 2002). Research suggests there are three common indirect measures of muscle damage used to determine the fatiguing effect of exercise; they are muscle soreness, blood protein assessment and maximal voluntary contraction force (Warren, Lowe, & Armstrong, 1999). Maximal voluntary contraction force is considered to be one of the most reliable indirect measures of post-exercise muscle damage (Warren, et al, 1999). It is widely accepted that concentric (shortening) exercise results in a strength loss of approximately 10-30% immediately post exercise, with strength returning to baseline levels within hours (Jones, Newhan, & Torgan, 1989). Similarly, eccentric (lengthening) exercise has also been shown to result in a 10-30% force loss immediately post-exercise, however there is a longer recovery period (approximately 24 hours post-exercise) compared with concentric exercise (Mizrahi, Verbitsky & Isakov, 2001). In addition, the appearance of muscle proteins in the blood post-exercise is also commonly used to indirectly determine muscle damage. The muscle enzymes which have been assessed include lactate dehydrogenase, asparate aminotransferase, carbonic anhydrase isoenzyme II and creatine Kinase (Sorichter, Puschendorf & Mair, 1999). Creatine kinase has received the most attention; however it has been shown to be an unreliable marker of muscle damage as it can be influenced by factors other than muscle damage, including genetic factors (Nosaka, & Clarkson, 1996). The final indirect marker of muscle damage is muscle soreness, which has been shown to appear many hours after exercise and is thought to peak approximately 24-48 hours post-exercise (Clarkson, Nosaka & Braum, 1992).
Post-exercise recovery techniques are commonly used to reduce the time it takes to recover from such exercise. It is common for athletes to utilise cold water immersion (COLD) following strenuous exercise to promote recovery, diminish muscle soreness and to minimise the time it takes to return to optimal performance capabilities (Cochrane, 2004). There is well established evidence which suggests that the use of cyrotherapy/COLD is beneficial in minimising the inflammatory response to injury (Paddon-Jones & Quigley, 1997; Cochrane, 2004). However the effect it has on DOMS or the time it takes to return to optimal performance capabilities has not been definitively stated (Eston & Peters, 1999; Hiruma, Okamune, Sasaki & Uminura, 2002; Hiruma, Terada, Saraki & Umimura, 1999). Recently CWI has been used as a form of recovery (Vaile, Gill & Blazevich, 2007). It is believed that CWI may be linked to changes in intra-muscular hydrostatic pressure by alternating vasoconstriction and vasodilation, which may lead to enhanced lactate removal (Vaile, et al, 2007). However, similarly to COLD, CWI has not been proven to reduce the negative effects associated with intense exercise (Vaile, et al, 2007). A study conducted by Coffey, Leveritt and Gill (2004) and reiterated by Dawson, Gow, Modra, Bishop and Stewart (2005) found that CWI at 4 hour and 48 hour post-high intensity exercise had no effect on performance. However, on the contrary, Vaile et al (2007) and Kuligowski, Lephart, Giannantonio, and Blanc (1998) found the use of CWI can help athletes return to baseline performance measures. However, the difference in protocols between those studies has been outlined as a potential reason for the varying results (Vaile, et al, 2007, Kuligowski, et al, 1998, Coffey, et al, 2004, Dawson, et al, 2005).
High levels athletes are repeatedly putting their bodies through high levels of stress, which inevitably results in muscle damage. This muscle damage can lead to decreases in performance and potential injury risks. Therefore it is not surprising that a great emphasis has been placed on determining superior recovery methods to return muscle performance back to baseline levels swiftly.
Background
Phases of Methodology
Outcomes
References