Repeatability of exercise behaviors in mice.
OBJECTIVE
Measurements of exercise behaviors in rodents such as maximal treadmill endurance and physical activity are often used in the literature; however, minimal data are available regarding the repeatability of measurements used for these exercise behaviors. This study assessed the repeatability of a commonly used maximal exercise endurance treadmill test as well as voluntary physical activity measured by wheel running in mice.


METHODS
Repeatability of treadmill tests were analyzed for both inbred and outbred mice in addition to a 10 week repeatability analysis using Balb/cJ mice (n=20). Voluntary daily physical activity was assessed by distance, duration, and speed of wheel running (WR). Physical activity measurements on days 5 and 6 of WR in a large cohort (n=739) of both inbred and outbred mice were compared.


RESULTS
No significant differences (p>0.05) in exercise endurance were found between different cohorts of Balb/cJ and DBA/2J mice indicating strains overall generally test the same; however, significant differences between tests were seen within BaD2F(2) animals (p<0.001). Bland-Altman analysis revealed a lack of agreement between weekly endurance tests within mouse, and correlation analysis showed lack of consistent correlations between weekly endurance tests within mouse. No significant differences were found for WR measurements within mouse between days (p=0.99). High correlations between days within mouse for WR were found (r=0.74-0.85).


CONCLUSIONS
High intra-mouse variability between repeated endurance tests suggests that treadmill testing in an enclosed chamber with shock grid for motivation to run in mice is not repeatable. Conversely, high correlation and agreement between days of wheel-running measurements suggest that voluntary activity (WR) is repeatable and stable within individual mice.
Knab
Amy M
AM
Department of Kinesiology, University of North Carolina, Charlotte, United States. knabam@appstate.edu
Bowen
Robert S
RS
Moore-Harrison
Trudy
T
Hamilton
Alicia Trynor
AT
Turner
Michael J
MJ
Lightfoot
J Timothy
JT
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D009043:Motor Activity / Q000235:genetics; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance / Q000235:genetics / Q000502:physiology*; D013045:Species Specificity