We would like to thank the Graduate Student Government Association, Office of Student Research, and the Department of Health and Exercise Science at Appalachian State University for providing funding to support this project. Additionally, we would like to thank Monique Eckerd and Therin Williams-Frey for overseeing daily operations of the animal research facility.

This study was approved by Appalachian State University&#39;s Institutional Animal Care and Use Committee (#22-05).
1. Animals
<ol>
	<li>Procure C57BL/6 mice from the in-house mouse colony. 
	NOTE: Male mice 5-8 months of age at the start of the study were used. Daily running activity peaks and plateaus at around 9-10 weeks of age26. Previous studies have demonstrated that old mice (22-24 months) will also perform loaded wheel running<sup class="...

<ol>
	<li>Frontera, W. R., Ochala, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Skeletal+muscle:+A+brief+review+of+structure+and+function.">Skeletal muscle: A brief review of structure and function.</a> Calcified Tissue International. 96 (3), 183-195 (2015).</li><li>Goldberg, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protein+synthesis+during+work-induced+growth+of+skeletal+muscle.">Protein synthesis during work-induced growth of skeletal muscle.</a> Journal of Cell Biology. 36 (3), 653-658 (1968).</li><li>Baar, K., Esser, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phosphorylation+of+p70S6k+correlates+with+increased+skeletal+muscle+mass+following+resistance+exercise.">Phosphorylation of p70S6k correlates with increased skeletal muscle mass following resistance exercise.</a> American Journal of Physiology-Cell Physiology. 276 (1), 120-127 (1999).</li><li>Wong, T. S., Booth, F. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Skeletal+muscle+enlargement+with+weight-lifting+exercise+by+rats.">Skeletal muscle enlargement with weight-lifting exercise by rats.</a> Journal of Applied Physiology. 65 (2), 950-954 (1988).</li><li>Hornberger Jr, T. A., Farrar, R. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiological+hypertrophy+of+the+FHL+muscle+following+8+weeks+of+progressive+resistance+exercise+in+the+rat.">Physiological hypertrophy of the FHL muscle following 8 weeks of progressive resistance exercise in the rat.</a> Canadian Journal of Applied Physiology. 29 (1), 16-31 (2004).</li><li>Zhu, W. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Weight+pulling:+A+novel+mouse+model+of+human+progressive+resistance+exercise.">Weight pulling: A novel mouse model of human progressive resistance exercise.</a> Cells. 10 (9), 2459 (2021).</li><li>Tamaki, T., Uchiyama, S., Nakano, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+weight-lifting+exercise+model+for+inducing+hypertrophy+in+the+hindlimb+muscles+of+rats.">A weight-lifting exercise model for inducing hypertrophy in the hindlimb muscles of rats.</a> Medicine and Science in Sports and Exercise. 24 (8), 881-886 (1992).</li><li>De Bono, J. P., Adlam, D., Paterson, D. J., Channon, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+quantitative+phenotypes+of+exercise+training+in+mouse+models.">Novel quantitative phenotypes of exercise training in mouse models.</a> American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 290 (4), 926-934 (2006).</li><li>Goh, J., Ladiges, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voluntary+wheel+running+in+mice.">Voluntary wheel running in mice.</a> Current Protocols in Mouse Biology. 5 (4), 283-290 (2015).</li><li>Lightfoot, J. T., Turner, M. J., Daves, M., Vordermark, A., Kleeberger, S. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+influence+on+daily+wheel+running+activity+level.">Genetic influence on daily wheel running activity level.</a> Physiological Genomics. 19 (3), 270-276 (2004).</li><li>Allen, D. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+and+skeletal+muscle+adaptations+to+voluntary+wheel+running+in+the+mouse.">Cardiac and skeletal muscle adaptations to voluntary wheel running in the mouse.</a> Journal of Applied Physiology. 90 (5), 1900-1908 (2001).</li><li>Ishihara, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+running+exercise+with+increasing+loads+on+tibialis+anterior+muscle+fibres+in+mice.">Effects of running exercise with increasing loads on tibialis anterior muscle fibres in mice.</a> Experimental Physiology. 87 (2), 113-116 (2002).</li><li>Kurosaka, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+voluntary+wheel+running+on+satellite+cells+in+the+rat+plantaris+muscle.">Effects of voluntary wheel running on satellite cells in the rat plantaris muscle.</a> Journal of Sports Science and Medicine. 8 (1), 51-57 (2009).</li><li>Lambert, M. I., Noakes, T. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spontaneous+running+increases+VO2max+and+running+performance+in+rats.">Spontaneous running increases VO2max and running performance in rats.</a> Journal of Applied Physiology. 68 (1), 400-403 (1990).</li><li>Rodnick, K. J., Reaven, G. M., Haskell, W. L., Sims, C. R., Mondon, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Variations+in+running+activity+and+enzymatic+adaptations+in+voluntary+running+rats.">Variations in running activity and enzymatic adaptations in voluntary running rats.</a> Journal of Applied Physiology. 66 (3), 1250-1257 (1989).</li><li>Sexton, W. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vascular+adaptations+in+rat+hindlimb+skeletal+muscle+after+voluntary+running-wheel+exercise.">Vascular adaptations in rat hindlimb skeletal muscle after voluntary running-wheel exercise.</a> Journal of Applied Physiology. 79 (1), 287-296 (1995).</li><li>Dungan, C. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Elevated+myonuclear+density+during+skeletal+muscle+hypertrophy+in+response+to+training+is+reversed+during+detraining.">Elevated myonuclear density during skeletal muscle hypertrophy in response to training is reversed during detraining.</a> American Journal of Physiology-Cell Physiology. 316 (5), 649-654 (2019).</li><li>Ishihara, A., Roy, R. R., Ohira, Y., Ibata, Y., Edgerton, V. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypertrophy+of+rat+plantaris+muscle+fibers+after+voluntary+running+with+increasing+loads.">Hypertrophy of rat plantaris muscle fibers after voluntary running with increasing loads.</a> Journal of Applied Physiology. 84 (6), 2183-2189 (1998).</li><li>Konhilas, J. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Loaded+wheel+running+and+muscle+adaptation+in+the+mouse.">Loaded wheel running and muscle adaptation in the mouse.</a> American Journal of Physiology-Heart and Circulatory Physiology. 289 (1), 455-465 (2005).</li><li>Legerlotz, K., Elliott, B., Guillemin, B., Smith, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voluntary+resistance+running+wheel+activity+pattern+and+skeletal+muscle+growth+in+rats:+Wheel+running+activity+pattern+and+muscle+growth.">Voluntary resistance running wheel activity pattern and skeletal muscle growth in rats: Wheel running activity pattern and muscle growth.</a> Experimental Physiology. 93 (6), 754-762 (2008).</li><li>Mobley, C. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progressive+resistance-loaded+voluntary+wheel+running+increases+hypertrophy+and+differentially+affects+muscle+protein+synthesis,+ribosome+biogenesis,+and+proteolytic+markers+in+rat+muscle.">Progressive resistance-loaded voluntary wheel running increases hypertrophy and differentially affects muscle protein synthesis, ribosome biogenesis, and proteolytic markers in rat muscle.</a> Journal of Animal Physiology and Animal Nutrition. 102 (1), 317-329 (2018).</li><li>D'Hulst, G., Palmer, A. S., Masschelein, E., Bar-Nur, O., De Bock, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voluntary+resistance+running+as+a+model+to+induce+mTOR+activation+in+mouse+skeletal+muscle.">Voluntary resistance running as a model to induce mTOR activation in mouse skeletal muscle.</a> Frontiers in Physiology. 10, 1271 (2019).</li><li>Soffe, Z., Radley-Crabb, H. G., McMahon, C., Grounds, M. D., Shavlakadze, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+loaded+voluntary+wheel+exercise+on+performance+and+muscle+hypertrophy+in+young+and+old+male+C57Bl/6J+mice:+Exercise+and+muscle+hypertrophy+in+old+mice.">Effects of loaded voluntary wheel exercise on performance and muscle hypertrophy in young and old male C57Bl/6J mice: Exercise and muscle hypertrophy in old mice.</a> Scandinavian Journal of Medicine and Science in Sports. 26 (2), 172-188 (2016).</li><li>White, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voluntary+resistance+wheel+exercise+from+mid-life+prevents+sarcopenia+and+increases+markers+of+mitochondrial+function+and+autophagy+in+muscles+of+old+male+and+female+C57BL/6J+mice.">Voluntary resistance wheel exercise from mid-life prevents sarcopenia and increases markers of mitochondrial function and autophagy in muscles of old male and female C57BL/6J mice.</a> Skeletal Muscle. 6 (1), 45 (2016).</li><li>Murach, K. A., McCarthy, J. J., Peterson, C. A., Dungan, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Making+mice+mighty:+Recent+advances+in+translational+models+of+load-induced+muscle+hypertrophy.">Making mice mighty: Recent advances in translational models of load-induced muscle hypertrophy.</a> Journal of Applied Physiology. 129 (3), 516-521 (2020).</li><li>Swallow, J. G., Garland, T., Carter, P. A., Zhan, W. -. Z., Sieck, G. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+voluntary+activity+and+genetic+selection+on+aerobic+capacity+in+house+mice+(Mus+domesticus).">Effects of voluntary activity and genetic selection on aerobic capacity in house mice (Mus domesticus).</a> Journal of Applied Physiology. 84 (1), 69-76 (1998).</li><li>Murach, K. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Late-life+exercise+mitigates+skeletal+muscle+epigenetic+aging.">Late-life exercise mitigates skeletal muscle epigenetic aging.</a> Aging Cell. 21 (1), 13527 (2022).</li><li>Mackay, A. D., Marchant, E. D., Louw, M., Thomson, D. M., Hancock, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exercise,+but+not+metformin+prevents+loss+of+muscle+function+due+to+doxorubicin+in+mice+using+an+in+situ+method.">Exercise, but not metformin prevents loss of muscle function due to doxorubicin in mice using an in situ method.</a> International Journal of Molecular Sciences. 22 (17), 9163 (2021).</li><li>Godwin, J. S., Hodgman, C. F., Needle, A. R., Zwetsloot, K. A., Andrew, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-body+heat+shock+accelerates+recovery+from+impact-+induced+skeletal+muscle+damage+in+mice.">Whole-body heat shock accelerates recovery from impact- induced skeletal muscle damage in mice.</a> Conditioning Medicine. 2 (4), 184-191 (2020).</li><li>Wen, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MyoVision:+Software+for+automated+high-content+analysis+of+skeletal+muscle+immunohistochemistry.">MyoVision: Software for automated high-content analysis of skeletal muscle immunohistochemistry.</a> Journal of Applied Physiology. 124 (1), 40-51 (2018).</li><li>Manzanares, G., Brito-da-Silva, G., Gandra, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voluntary+wheel+running:+Patterns+and+physiological+effects+in+mice.">Voluntary wheel running: Patterns and physiological effects in mice.</a> Brazilian Journal of Medical and Biological Research. 52 (1), 7830 (2019).</li><li>Bartling, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex-related+differences+in+the+wheel-running+activity+of+mice+decline+with+increasing+age.">Sex-related differences in the wheel-running activity of mice decline with increasing age.</a> Experimental Gerontology. 87, 139-147 (2017).</li><li>Zwetsloot, K. A., Westerkamp, L. M., Holmes, B. F., Gavin, T. 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Existing resistance exercise models in rodents have proven invaluable for skeletal muscle research; however, many of these models are invasive, involuntary, and/or time- and labor-intensive. LWR is an excellent model that not only induces similar muscular adaptations as those observed in other well-accepted resistance exercise training models, but also provides a chronic, low-stress exercise stimulus for the animal with minimal time/labor commitment by the researcher. Additionally, since LWR models require minimal direct...

Skeletal muscle mass comprises approximately 40% of body mass in adult humans; thus, maintaining skeletal muscle mass throughout life is critical. Skeletal muscle mass plays an integral role in energy metabolism, maintaining core body temperature, and glucose homeostasis1. The maintenance of skeletal muscle is a balance between protein synthesis and protein degradation, but many gaps still exist in the understanding of the intricate molecular mechanisms that drive these processes. To study the molecular mechanisms that regulate the maintenance and growth of muscle mass, human subjects&#39; research models often employ resistance exercise-based interventions, since mechanical stimuli play an integral role in the regulation of skeletal muscle mass. While human subjects research has been successful, the time necessary to exhibit adaptations and ethical concerns regarding invasive procedures (i.e., muscle biopsies) limit the quantity of data that can be obtained. While the adaptations to resistance exercise are fairly ubiquitous across mammalian species, animal models provide the benefit of being able to precisely control the diet and exercise regimen while also allowing for the collection of whole tissues throughout the body, such as the brain, liver, heart, and skeletal muscle.
Many resistance training models have been developed for use in rodents: synergistic ablation2, electrical stimulation3,4, weighted ladder climbing5, weighted sled pulling6, and canvassed squatting7. It is evident that all of these models, if done correctly, can be effective models to induce skeletal muscle adaptations, such as hypertrophy. However, the downfalls of these models are that they are mostly involuntary, not part of normal rodent behavior, time-/labor-intensive, and invasive.
Fortunately, many mouse and rat strains voluntarily run long distances when given access to a running wheel. Moreover, free-running wheel (FWR) exercise models do not rely on extensive conditioning, positive/negative reinforcement, or anesthesia to force movement or muscle activity8,9. Running activity depends greatly on mouse strain, sex, age, and an individual basis. Lightfoot et al. compared the running activity of 15 different mouse strains and found that daily running distance ranges from 2.93 km to 7.93 km, with C57BL/6 mice running the farthest, regardless of sex10. FWR is commonly accepted as an excellent model for inducing endurance adaptations in skeletal and cardiac muscles11,12,13,14,15,16; however, utilizing wheel running in resistance training models is less commonly investigated.
As one could suspect, the hypertrophic effect of wheel running might be augmented by adding resistance to the running wheel, termed loaded wheel running (LWR), thus requiring greater efforts to run on the wheel to more closely mimic resistance training. Using varied methods of load application, previous studies have demonstrated that the LWR model utilizing rats and mice routinely displayed increases in limb muscle mass of 5%-30% in a matter of 6-8 weeks17,18,19,20,21. Furthermore, D&#39;hulst et al. demonstrated that a single bout of LWR led to a 50% greater increase&#160;in activation of the protein synthesis signaling pathway compared to FWR22. Wheel resistance has been most commonly applied by a friction-based, constant loading method, whereby a magnetic brake or tension bolt is utilized to apply wheel resistance12,19,23,24. One caveat of the friction-based, constant load method is that when moderate to high resistance is applied, the animal cannot overcome the high resistance to initiate movement of the wheel, effectively ceasing training. Most importantly, many of the cage and wheel systems used for rodent running wheel models are quite costly and require specialized equipment.
Recently, Dungan et al. developed a progressive weighted-wheel-running (PoWeR) model, which applies a load to the wheel asymmetrically via external masses adhered to a single side of the wheel. The unbalanced wheel loading and variable resistance of the PoWeR model are thought to encourage continued running activity and promote shorter bursts of loaded wheel running in mice, more closely imitating the sets and repetitions performed with resistance training17. Despite the average running distance being 10-12 km per day, the PoWeR model yielded a 16% and 17% increase in plantaris muscle wet mass and fiber cross-sectional area (CSA), respectively. Despite many practical advantages, the PoWeR model of LWR does have some limitations. As recognized by the authors, the PoWeR model is a high-volume &#34;hybrid&#34; stimulus that is reflective of a blended endurance/resistance exercise model (i.e., concurrent training in humans), as opposed to a more strictly resistance exercise-based model, potentially introducing an interference effect and contributing to the less pronounced hypertrophy or different mechanisms by which hypertrophy is induced25. Ensuring that a concurrent training phenomenon does not occur in what is intended to be a resistance exercise training model is imperative. Therefore, the PoWeR model was modified to develop a LWR model that utilizes higher loads than previously used to more closely resemble a resistance training model. Herein, details are provided for a simple and inexpensive 9 week progressive resistance training LWR model in C57BL/6 mice.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1 g disc neodymium magnets</td>
			<td>Applied Magnets</td>
			<td>ND018-6</td>
			<td>Used for all sensor magnets and 1 g increments of wheel loading</td>
		</tr>
		<tr>
			<td>2.5 g disc neodymium magnets</td>
			<td>Applied Magnets</td>
			<td>ND022</td>
			<td>Used for 2.5 g increments of wheel loading</td>
		</tr>
		<tr>
			<td>8-32 x 1&#34; stainless steel screws</td>
			<td>Amazon</td>
			<td></td>
			<td>https://www.amazon.com/gp/product/B07939RS23/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&#38;psc=1</td>
		</tr>
		<tr>
			<td>8-32 Wing Nuts</td>
			<td>Amazon</td>
			<td></td>
			<td>https://www.amazon.com/gp/product/B07YYWW2SB/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&#38;th=1</td>
		</tr>
		<tr>
			<td>10 &#181;L pipette tip box (empty)</td>
			<td>Thermo Scientific</td>
			<td>2140</td>
			<td>We used empty ART Pipette tip boxes, but any similar sized boxes/trays would suffice</td>
		</tr>
		<tr>
			<td>Extreme Liquid Glue</td>
			<td>Loctite</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Laminin primary antibody</td>
			<td>Novus Biologicals</td>
			<td>NB300-144AF647</td>
			<td>primary antibody conjugated with AF657; 1:200 in PBS containing 10% normal goat serum</td>
		</tr>
		<tr>
			<td>Lithium 3 V battery</td>
			<td>n/a</td>
			<td>CR2032</td>
			<td></td>
		</tr>
		<tr>
			<td>M10 (3/16&#34; x 1 1/4&#34;) stainless steel fender washers</td>
			<td>Amazon</td>
			<td></td>
			<td>https://www.amazon.com/gp/product/B00OHUHEU8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&#38;th=1</td>
		</tr>
		<tr>
			<td>MyoVision: Automated Image Quantification Platform&#160;</td>
			<td>Wen et al. (2017)</td>
			<td>v1.0</td>
			<td>https://www.uky.edu/chs/center-for-muscle-biology/myovision</td>
		</tr>
		<tr>
			<td>Polycarbonate rodent cage (430 mm L x 290 mm W x 201 mm H), with narrow width stainless steel wired bar lid</td>
			<td>Orchid Scientific</td>
			<td>Polycarbonate Rat Cage Type II</td>
			<td>https://orchidscientific.com/product/rat-cage/ - 1519974600758-c29bc1c5-6dfa</td>
		</tr>
		<tr>
			<td>Sigma Sport 509 Bike Computer</td>
			<td>Sigma Sport</td>
			<td></td>
			<td>Does not need to be this model in particular, but must have distance and time monitoring capabilities</td>
		</tr>
		<tr>
			<td>Silent Spinner Running Wheel (mini 11.4 cm)</td>
			<td>Kaytee</td>
			<td>SKU# 100079369</td>
			<td>https://www.kaytee.com/all-products/small-animal/silent-spinner-wheel</td>
		</tr>
	</tbody>
</table>

a simple and inexpensive running wheel model for progressive resistance training in mice

Previously developed rodent resistance-based exercise models, including synergistic ablation, electrical stimulation, weighted-ladder climbing, and most recently, weighted-sled pulling, are highly effective at providing a hypertrophic stimulus to induce skeletal muscle adaptations. While these models have proven invaluable for skeletal muscle research, they are either invasive or involuntary and labor-intensive. Fortunately, many rodent strains voluntarily run long distances when given access to a running wheel. Loaded wheel running (LWR) models in rodents are capable of inducing adaptations commonly observed with resistance training in humans, such as increased muscle mass and fiber hypertrophy, as well as stimulation of muscle protein synthesis. However, the addition of moderate wheel load either fails to deter mice from running great distances, which is more reflective of an endurance/resistance training model, or the mice discontinue running nearly entirely due to the method of load application. Therefore, a novel high-load wheel running model (HLWR) has been developed for mice where external resistance is applied and progressively increased, enabling mice to continue running with much higher loads than previously utilized. Preliminary results from this novel HLWR model suggest it provides sufficient stimulus to induce hypertrophic adaptations over the 9 week training protocol. Herein, the specific procedures to execute this simple yet inexpensive progressive resistance-based exercise training model in mice are described.

In this study, 24 C57BL/6 mice (6.3 &#177; 0.7 months at the start of this study) were randomly assigned to one of three treatment groups: sedentary (SED), loaded wheel running (LWR; same as PoWeR described by Dungan et al.17), or high LWR (HLWR), and then completed their respective 9 week protocol. After the acclimation week (week 1), there were no group or group x time differences in running distance or training volume (Figure 5).
<p class="jove_content biglegen...

Watch this Scientific Journal Video about A Simple and Inexpensive Running Wheel Model for Progressive Resistance Training in Mice at JoVE.com

A Simple and Inexpensive Running Wheel Model for Progressive Resistance Training in Mice

This procedure describes a translatable progressive loaded running wheel resistance training model in mice. The primary advantage of this resistance training model is that it is entirely voluntary, thus reducing stress for the animals and the burden on the researcher.

Previously developed rodent resistance-based exercise models, including synergistic ablation, electrical stimulation, weighted-ladder climbing, and most ...

This protocol allows researchers to resistance train large cohorts of mice at a much lower cost compared to models that use commercially available running wheel equipment. The primary advantage of this resistance training model is that it is entirely voluntary, which reduces stress for the animals and time commitment for the researcher. This model can help better understand the cellular and molecular mechanisms that regulate muscle mass in response to exercise training.By design, this loaded wheel running model is relatively simple to execute. However, it is still recommended that researchers perform pilot testing in the unique laboratory setting to estimate the running performance of mice prior to experimentation. Demonstrating this procedure will be PJ Koopmans, a graduate research assistant in my laboratory.To set up the running wheel apparatus, glue a single one gram sensor magnet to the outer middle circumference of the running wheel and use this wheel for only the first week of wheel acclimation. Loaded wheel running requires two grams of load, hence glue two magnets of one gram side by side onto the outer circumference of the wheel. A tape can be used to hold the magnets in place until the glue firmly dries.As the weeks pass, apply additional load in weeks 3, 4, 5, and 7 by placing another one gram magnet on top of either magnet already present. As these magnets firmly adhere to one another, no glue will be required. High loaded wheel running setup requires three sets of wheels.The first set of wheels, which is required for week two only has a single 2.5 gram magnet glued onto the outer circumference of the wheel. The second set of wheels, which is required for week three only, has two 2.5 gram magnets glued side by side onto the outer circumference of the wheel. The third set of wheels required for four weeks and beyond has three 2.5 gram magnets glued side by side onto the outer circumference of the wheel.Apply additional load for week six and eight by placing another 2.5 gram magnet on top of either of the magnets already present. Ensure that a fresh battery is inserted into the bike computer before the assembly. Then assemble the running wheels using a cage equipped with a digital bike computer to monitor time and distance traveled during exercise.The average speed in kilometers per hour is derived arithmetically. Set the wheel size during initial bike computer programming and calculate per revolution distance by measuring the outer circumference of the running wheel. To ensure that all computer and sensor components are contained within a solid barrier outside the cage to prevent mice from chewing on the components, utilize the lid of an empty pipette tip box with a small rectangle cutout for the magnetic bike sensor and the main part of the box to hold the bike computer, and wire.Drill two holes through the corners of the pipette tip box lid to secure the magnetic bike sensor and running wheel stand in place on the outside of the cage and insert the running wheel base upside down through the gaps in the cage lid but on top of the solid surface. Secure the wheel base and computer sensor to the top of the cage with hardware. Ensure that the bike computer sensor and the pipette tip box lid is directly above where the sensor magnet of the wheel is located and that the sensor magnet and computer sensor are spaced no more than one centimeter apart to allow the proper recording of wheel movement.Attach the appropriate running wheel to the wheel base before placing the lid onto the cage, then securely placing the lid onto the cage. With the wheel hanging from the cage lid, ensure at least 2.5 centimeters of clearance from the cage floor. Then place a minimal amount of bedding material in the cage to ensure that the wheel spins freely but does not become impeded by the buildup of bedding.As mice are an nocturnal species, most of their natural cage activity, including wheel running, will be performed during the dark hours of the light cycle. During the experiment, record this data from the bike computer at a consistent interval scheduled to ensure accurate activity monitoring. Individually house sedentary mice for nine weeks in a cage containing a locked running wheel to prevent any running.Reduce load for the loaded wheel running and high loaded wheel running groups if necessary to ensure that mice continue to exercise for the entire nine a week protocol as per the loading schedule. During the study, mice were randomly assigned to one of three treatment groups, namely sedentary, loaded wheel running, or high loaded wheel running, and then completed their respective nine week protocol. After the one week of acclimation, there were no group or group by time differences in running distance or training volume.Normalized soleus mass was 21.4%larger in the high loaded wheel running group than in the sedentary group despite no difference in fiber cross-sectional area. Although plantaris muscle mass and average fiber cross-sectional area did not displace statistically significant differences, there appears to be a shift in the the proportion of fibers with a larger cross-sectional area in the plantaris of high loaded wheel running compared to sedentary and loaded wheel running. There were no significant differences in twitch or peak force of the GPS complex between groups as measured by an NC2 muscle function test.It is important to ensure the wheel spins freely within the cage and that the wheel sensor magnet is close to the bike computer sensor so wheel rotation is unimpeded and the bike computer accurately records running data. Following this procedure, researchers can perform subsequent analyses such as contractile function or immunohistochemical techniques to examine the various physiological responses further to exercise training.

a-simple-inexpensive-running-wheel-model-for-progressive-resistance

Research

JoVE Journal

Biology

3.0K vistas.  Appalachian State University. Este protocolo permite a los investigadores entrenar a grandes cohortes de ratones a un costo mucho menor en comparación con los modelos que utilizan equipos de ruedas disponibles comercialmente. La principal ventaja de este modelo de entrenamiento de resistencia es que es totalmente voluntario, lo que reduce el estrés para los animales y el compromiso de tiempo para el investigador. Este modelo puede ayudar a comprender mejor los mecanismos celulares y moleculares que regulan la masa muscu...