An isotonic contraction can be concentric, which is where the muscle shortens as the fibres contract or eccentric, where the fibres contract as the muscle lengthens. When a muscle contracts with no resulting movement, it is an isometric contraction. Page: 1  1. 2  2. 3  3. 4  4. 5  5. 6  Back.
how much propane will i use i will be building an ig pool and ig spa 7ft spa i will be heating the spa with a 400k btu propane heater i would like to heat the pool a couple of time per year for special events local code limits the size of a propane tank to 125 gallons anything bigger will require a permit from the fire dept
New gas swimming pool heaters have a standard test they go through to determine their energy efficiency based on their Btu (British thermal unit) output. Heater efficiency is the ratio of usable output to energy input. For example, an 80%-efficient heater uses $80 worth of useful heat for every $100 worth of fuel.Therefore, it wastes 20% of the fuel. Most gas pool heaters feature their efficiency percentage on their nameplates. A pool heater's manufacturer can also provide its efficiency percentage.Today, you'll find some gas pool heaters with 89%â95% efficiency. The following table shows how much you can save for every $1,000 in annual pool heating costs by installing a gas pool heater that's 95% efficient.or example, an 80%-efficient heater uses $80 worth of useful heat for every $100 worth of fuel. Therefore, it wastes 20% of the fuel. Most gas pool heaters feature their efficiency percentage on their nameplates. A pool heater's manufacturer can also provide its efficiency percentage.