The Influence of Rowing-related Postures Upon Respiratory Muscle Pressure and Flow Generating Capacity

During the rowing stroke, the respiratory
muscles are responsible for postural control, trunk stabilisation,
generation/transmission of propulsive forces and
ventilation (Bierstacker et al. in Int J Sports Med 7:73–79,
1986; Mahler et al. in Med Sci Sports Exerc 23:186–193,
1991). The challenge of these potentially competing
requirements is exacerbated in certain parts of the rowing
stroke due to flexed (stroke ‘catch’) and extended postures
(stroke ‘finish’). The purpose of this study was to assess the influence of the postural role of the trunk muscles upon
pressure and flow generating capacity, by measuring
maximal respiratory pressures, flows, and volumes in various
seated postures relevant to rowing. Eleven male and
five female participants took part in the study. Participants performed two separate testing sessions using two different testing protocols. Participants performed either maximal inspiratory or expiratory mouth pressure manoeuvres (Protocol 1), or maximal flow volume loops (MFVLs) (Protocol 2), whilst maintaining a variety of specified supported or unsupported static rowing-related postures. Starting lung volume was controlled by initiating the test breath in the upright position. Respiratory mouth pressures tended to be lower with recumbency, with a significant decrease in PEmax in unsupported recumbent postures (3–9 % compared to upright seated; P = 0.036). There was a significant decrease in function during dynamic
manoeuvres, including PIF (5–9 %), FVC (4–7 %) and
FEV1 (4–6 %), in unsupported recumbent postures
(p\0.0125; Bonferroni corrected). Thus, respiratory
pressure and flow generating capacity tended to decrease
with recumbency; since lung volumes were standardised,
this may have been, at least in part, influenced by the
postural co-contraction of the trunk muscles.