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Muscles are required to perform or absorb mechanical work under different conditions. Muscle is a dynamic organ capable of significant remodeling and adapting to external loading environments such as tension and length changes (Gao et al., 2011). The sural region also known as the calf region are one of the heavily used muscles in the human body and injuries to the muscles as a result of heavy exertion are an area of great concern. The ability of a calf muscle to do mechanical work, depends on the interaction between its contractile components (calf muscles) and its elastic components (Achilles tendon) constituting the posterior compartment of the leg muscle. To understand the mechanics of human muscle contraction, it is important to distinguish the roles of the contractile components and also the elastic components (Lichtwark & Wilson, 2006). Apart from the ability of calf muscle to perform mechanical work, it’s essential for maintenance of venous circulatory adequacy during upright posture and activity (O’Donovan et al., 2009; Goldhaber, 2003).
Dorsiflexion defined as flexion of the foot in an upward direction, is an effective exercise used for maintaining venous circulatory adequacy during upright posture and activity. Contractile activity of calf muscles occurs only during stance phase and these muscles function either to provide resistance to dorsiflexion or to cause active plantar flexion (Simon et al., 1978).
Hence, it becomes extremely important to understand calf contraction in order to understand dorsiflexion.
A number of techniques are being used to analyze superficial compartment of leg during dorsiflexion. Ultrasonography is a primary technique being used to measure contraction – induced shortening during plantar flexion of leg muscles. The length change of the human Gastrocnemius muscle and Soleus muscles during repeated isometric plantar-flexion loading was measured in vivo to assess their contractile behaviour (Corrigan et al., 2008). Magnetic resonance imaging (MRI) along with calf venography has been used to suspect calf related problems (Vukov et al., 1991).
Multiple methods have been suggested in the past to prevent the injuries to the calf muscles using physical exercises. The major remedies or physical exercises include Nerve tension test (Godges et al., n.d.), calf stretching exercise (Patla & Abbott, 2003) and sometimes surgical (Bailie & Kelikian, 2008) release of the ligament is often used to cure the syndrome.
Digital Imagery has been used over a number of years to compute and evaluate strain for a number of applications. 1-D time delay estimation techniques were used initially for displacement and strain estimation (O’Donnell et al, 1994) while the evaluation of 2-D strain has been developed, using both B-mode data (Chaturvedi et al., 1998) and raw radio frequency (rF) data (Chen et al., 2004). Apart from the biomedical application, digital imaging has made its mark in a number of other applications including the measurement of deformation and strain in sheet metal forming analysis, automotive crash testing, rail vehicle safety (Kirkpatrick et al., 2001), air-plane safety (Marzougui et al., 1999) etc. The methodology is also applied for quantitative evaluation of in-plane deformation characteristics of geo-materials (Watanabe et al., 2005), and also in medical fields to evaluate local failure of bone (Thurner et al., 2005).