COMPARISON OF METHODS FOR ASSESSMENT OF EXERCISE-INDUCED MECHANICAL HYPOALGESIA
Grancharska, K., Pencheva N.
South-West University, Sport and Kinesitherapy Dept., Bulgaria

Key words: exercise-induced hypoalgesia, pain assessment, cuff algometry

Introduction
Methodologies for evaluation of mechanically-induced hypoalgesia related with physical loading are less investigated. The aim of this study was to compare and to assess advantages and disadvantages of the following methods for experimental pain assessment, applied before and after exercise: - tourniquet algometry (TA); - hand-held algometry (HHA); and - computer-controlled cuff pressure algometry (CA).

Methods
Pressure pain threshold (PPT) and pain tolerable threshold (PTT) in healthy, untrained males were determined, before and after incremental test to exhaustion. The TA was applied with blood pressure apparatus to 10 subjects (19.1±1.2 years) and assessed with verbal scale (VS). Algometer Somedic was used for HHA. It was applied to five points upon m. gastrocnemius-soleus (GS) in 11 subjects (22.3±1.1 years) and assessed with VS. The experimental setup for CA, according to Stoilov et al., 2009 was applied to 12 males (23.7±3.4 years), consisted of an electro-pneumatic regulator (0-2 kPa/s range) with a tourniquet cuff, electronic visual analogue scale and quantitative evaluation of pressure-time-pain curves.

Results
The hypoalgesia after exercise, was established with: - TA, although in some subjects the PTT values were underestimated; - HHA in GS the PPT (kPa/cm2) for lateral and medial head, before or after exercise were: 464.8±148.3 or 676.0 ± 166.4 and 399.9±133.9 or 521.5± 90.6, respectively. The differences between values (kPa) of PPT and PTT, obtained with CA, and calculated before and after exercise, were 4.8 and 7.4, respectively. The similar tendency was proved with compression rates of 0.25, 0.50;1.00 kPa/s. The pressure – time and pain –time curves were linear with different slope.

Discussion
Although, the TA is an easy way to evaluate changes in pain perception, it did not allow assessment of manifested hypoalgesia, especially in trained males after exercise to exhaustion (Koltyn, 2000). HHA allows evaluation of PPT in different points of the muscle tested, but it is not suitable for PTT and has high variability (Giburm et al., 2011). The advantages of CA, as a novel experimental technique, is the precise quantitative evaluation of stimulus-response pressure-pain function (Jespersen et al., 2007), but it is not suitable for specific location of the muscle and for field application.

References
Giburm P, Chan W K, Si Bog P, Mi Jung K, Seong H J. (2011). Ann Rehabil Med, 35, 412-417.
Jespersen A, Dreyer L, Kendall S. et al. (2007), Pain 131, 57–62.
Koltyn K F. (2000). Sports Med 29 (2), 85-98.
Stoilov A, Pencheva N, Ivanov K. (2009), SRJ of SWU, 2 (1), 21-28.

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