Submitted on September 15, 2004
Accepted on December 16, 2004
ALBUTEROL AIDS RESISTANCE EXERCISE IN REDUCING UNLOADING-INDUCED ANKLE EXTENSOR STRENGTH LOSSES
John Caruso1*, John Hamill2, Miki Yamauchi2, Dean Mercado3, Tim Cook3, Brian Higginson3, Sean O'Meara3, Jeff Elias2, and Steve Siconolfi4
1 Exercise Physiology Laboratory, University of Nevada, Reno, Nevada, USA; Healthcare Research Associates, Orlando, Florida, USA
2 Exercise Physiology Laboratory, University of Nevada, Reno, Nevada, USA
3 Movement Science Laboratory, Montana State University, Bozeman, Montana, USA
4 School of Health Services & Human Performance, Ithaca College, Ithaca, New York, USA
* To whom correspondence should be addressed. E-mail: john-caruso{at}utulsa.edu.
While resistance exercise (REX) reduces ankle extensor (AE) mass and strength deficits during short-term unloading; additional treatments, concurrently administered with REX,
are required to attenuate the greater losses seen with longer unloading periods. Subjects performed left leg REX, which otherwise refrained from ambulatory and weight-bearing
activity for 40 days, while randomized to a capsule (placebo, albuterol) dosing regimen with no crossover to note if albuterol helps REX mitigate unloading-induced AE losses. A third group of subjects served as unloaded controls (CTRL). On days 0, 20 and 40 the following data were collected from the left leg: calf cross-sectional area (CSA) and AE strength measures. CSA was estimated using anthropometric methodology while AE strength data were obtained from eight unilateral calf press repetitions on an inertialbased REX device. Repeated-measures mixed-factorial 3x3 ANCOVAs with day 0 values as a covariate revealed group by time interactions for the strength variables eccentric total work (ETW) and average power (EAP). Tukeys HSD shows REX-placebo subjects incurred significant ETW and EAP losses by day 40 while the REX-albuterol treatment evoked strength gains to those same variables without concurrent muscle accretion. Corresponding concentric variables did not display similar changes. Day 40 CTRL data significantly declined for many variables; relative to the REX-albuterol
treatment some losses were significant after 20 days. ETW and EAP gains to unloaded AE may be due to one or more mechanisms. Continued research identifying mechanisms
responsible for such changes, as well as the safety of REX-albuterol administration in other models, is warranted.
