Loading of trained inspiratory muscles speeds lactate recovery kinetics

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Brown, P.I., Sharpe, G.R. ORCID: 0000-0002-4575-2332 and Johnson, M.A. ORCID: 0000-0002-8226-9438, 2010. Loading of trained inspiratory muscles speeds lactate recovery kinetics. Medicine and Science in Sports and Exercise, 42 (6), pp. 1103-1112. ISSN 0195-9131

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Official URL: http://dx.doi.org/10.1249/MSS.0b013e3181c658ac

Abstract

Purpose: To investigate the effects of inspiratory muscle loading (ITL) and inspiratory muscle training (IMT) upon blood lactate concentration ([lacj]B)and acid-base balance following maximal incremental cycling.

Methods: 18 subjects were divided into a control (n = 9) or IMT group (n = 9). Prior to and following a 6 wk intervention subjects completed two maximal incremental cycling tests followed by 20 min of recovery with (ITL) or without (passive recovery; PR) a constant inspiratory resistance (15 cmH2O). The IMT group performed 6 wk pressure threshold IMT at 50% maximal inspiratory mouth pressure (MIP). Throughout recovery, acid-base balance was quantified using the physicochemical approach by measuring the strong ion difference ([SID])=[Na+]+[K+]-[ Clj]+[ lacj]), the total concentration of weak acids ([Atot j]) and the partial pressure of carbon dioxide (PCO2).

Results: Following the intervention MIP increased in the IMT group only (+34%). No differences in lactate clearance were observed between PR and ITL before the intervention in both groups and following the intervention in the control group. Following IMT, relative to PR, [lacj]B was reduced throughout ITL (min 2 to 20) by 0.66 ± 1.28 mmol·L-1 (P<0.05) and both the fast (lactate exchange) and slow (lactate clearance) velocity constants of the lactate recovery kinetics were increased (P<0.05). Relative to pre-IMT, ITL reduced plasma [H+] which was accounted for by an IMT-mediated increase in [SID] due almost exclusively to a 1.7 mmol·L-1 reduction in [lacj]B.

Conclusions: Following maximal exercise ITL affected lactate recovery kinetics only after IMT. Our data support the notion that the inspiratory muscles are capable of lactate clearance which increases [SID] and reduces [H+]. These effects may facilitate subsequent bouts of high-intensity exercise.

Item Type:

Journal article

Publication Title:

Medicine and Science in Sports and Exercise

Creators:

Brown, P.I., Sharpe, G.R. and Johnson, M.A.

Publisher:

Lippincott Williams & Wilkins for the American College of Sports Medicine

Place of Publication:

Indianapolis, IN

Date:

2010