A stretching program increases the dynamic passive length and passive resistive properties of the calf muscle-tendon unit of unconditioned younger women

Clinical Kinesiology Research Laboratory, The School of Physical Therapy and Rehabilitation Science, The University of Montana, Missoula, MT 59812-4680, USA.
Arbeitsphysiologie (Impact Factor: 2.3). 03/2007; 99(4):449-54. DOI: 10.1007/s00421-006-0366-7
Source: PubMed

ABSTRACT This study examined the effects of a 6-week stretching program on the dynamic passive elastic properties of the calf muscle-tendon unit (MTU) of unconditioned younger women. After random assignment of 12 women (age 18-31 years) to a stretching group (SG) or to a control group (CG), six subjects in the SG and four subjects in the CG completed the study. For the initial tests, a Kin-Com dynamometer moved the ankle from plantarflexion to maximal dorsiflexion (DF) with negligible surface EMG activity in the soleus, gastrocnemius and tibialis anterior muscles. Angular displacement, passive resistive torque, area under the curve (passive elastic energy) and stiffness variables were reduced from the passive DF torque curves. The SG then completed ten static wall stretches held 15 s each, five times a week for 6 weeks, the CG did not. The tests were repeated and the changes between the tests and retests were examined for group differences (Mann-Whitney U). The SG had significant increases in the maximal passive DF angle (7 degrees +/- 4 degrees ), maximal passive DF torque (11.2 +/- 8.3 N m), full stretch range of motion (23 degrees +/- 24 degrees ), full stretch mean torque (3.4 +/- 2.1 N m), and area under the full stretch curve (22.7 +/- 23.5 degrees N m) compared to the CG (P < or = 0.019). The passive stiffness did not change significantly. The results showed that a stretching program for unconditioned calf MTUs increased the maximal DF angle and length extensibility, as well as the passive resistive properties throughout the full stretch range of motion. The adaptations within the calf MTU provide evidence that stretching enhances the dynamic passive length and passive resistive properties in unconditioned younger women.

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    • "), Immobilization in lengthened position (Tabary et al. 1972; Pontén and Fridén 2008; Williams and Goldspink 1971; Pattullo et al. 1992; Goldspink and Scutt 1992), stretch regimen (Nordez et al. 2009; Gajdosik et al. 2007; Nordez et al. 2006; LaRoche and Connolly 2006; Nakamura et al. 2012; Reid and Mcnair 2004; Goldspink 1999) Sarcomeres in series ↑ (Makarov et al. 2009; Boakes et al. 2007; Lindsey et al. 2002; Simpson and Williams 1995; Williams and Goldspink 1971; Tabary et al. 1972; De Deyne 2002) Sarcomere length ↑ (Makarov et al. 2009; Elsalanty et al. 2007) Slower MHC ↑ (De Deyne et al. 1999; Goldspink and Scutt 1992) Fiber length ↑ (Makarov et al. 2009; Elsalanty et al. 2007; Lindsey et al. 2002) Slower fiber type ↑ (Pattullo et al. 1992; De Deyne et al. 1999) Passive stiffness ↑ (Reid and Mcnair 2004; Williams et al. 1998), mixed (Nordez et al. 2006), NC (LaRoche and Connolly 2006; Gajdosik et al. 2007) ECM ↑ (Pontén and Fridén 2008) Collagen ↑ (Williams et al. 1998) Pennation angle ↓ (Elsalanty et al. 2007) Fascicle length ↑ (Boakes et al. 2007; Elsalanty et al. 2007; Williams et al. 1998; Simpson and Williams 1995) "
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    • "Stretching routines are an integral part of fitness and applied in sport, recreational and clinical environments (Magnusson et al., 1996; Gajdosik et al., 2007; Morse et al., 2008). Despite the widespread use of many different stretching modalities, limited knowledge exists regarding its mechanisms and efficacy . "
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    • "Results from quality assessment are presented in Table 1. Of the studies selected for inclusion, 13 featured a control group [2,3,5,12,16,18,19,21],[23,25,29,31,32,38]. Sixteen of the included studies randomly assigned participants to treatment groups [1-3,5,12,14-16,18,19,21,23],[25,29,31,32], nine studies featured blinding of the participants, assessors or therapists [1,2,12,13,16,19,21,31],[38] and 13 studies reported on the reliability of the measures used [1,3,5,12,14,16,23,25],[27,29-32]. "
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