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Twenty two healthy school
boys in the age group of 13-16 (14.5 ± 1.25, SEM) years who had
received training in yoga for three months and were able to perform mukh
bhastrika properly, were recruited for this study. They were briefed about
the study protocol and informed consent was obtained from them as well as
their parents. Recordings were taken in an air-conditioned laboratory
(room temperature 27 ± 1°C) two hours after a light breakfast. To avoid
the effect of lateralised stimulus, visual and auditory signals were given
from the front of the subject who was instructed to use his dominant hand
while responding to the signal (1, 15). RT was measured using a circuit
that had a DC source, two tap keys, a magnetic time marker and
visual/auditory signal source arranged in series. Signals obtained by
operating the tap keys were recorded on RM 6000 polygraph (Nihon Kohden
Corporation, Japan). Measurements were taken before and after nine rounds
of mukh bhastrika by asking the subject to open as quickly as he could, a
tap key that was connected alternatively to a light or sound source.
Stimulus applied by completing the circuit was marked by upward deflection
of the signal whereas subject’s response by breaking the circuit was
marked as a downward deflection. RT was calculated as the time between
these two deflections. The signals thus obtained were converted into
digital format by analog-digital converter (Mi², USA) and analyzed with
the help of data processing software (Bio Windows, Modular Instruments
Inc. USA). With this software the RT was obtained with an accuracy of 1
ms. More than ten trials were recorded and mean of three similar
observations was taken as a single value for statistical analysis (1). The
data was analyzed using Student’s paired ‘ t’ test and P values less
than 0.05 were accepted as indicating significant difference between the
compared values. |
