To the outside observer, snorkeling and scuba diving masks are no different from one another. But there are subtle variations that make a world of difference, especially underwater. Choose the best mask for you aquatic adventures by understanding how snorkeling and scuba diving masks stack up.

Across the country, the number of people who use bicycles to commute to work, though still small, has been increasing, reports the League of American Bicyclists. For example, in Portland, Oregon, 6 percent of people commuted to work by bike in 2007.

Although not as high in healthy omega-3 fatty acids as some saltwater fish, freshwater fish are a nutritious choice for lunch or dinner. Most freshwater fish are low in fat and high in protein. One serving of most freshwater fish provides more than 30 percent of the dietary reference intake of protein for adults.

A number of gym activities can be translated into a classroom environment. They work well because they require minimal or no equipment and you can do them in confined spaces.

Fishermen commonly use bait to lure a fish into biting their hook. Not all bait is created equal, however, and there are many kinds.

If you ride your bike for exercise or endurance training, rather than for casual jaunts around your neighborhood, you may have found your legs feeling tired and weak at times. That feeling can be frustrating, especially if you’re anxious to get back your bike or engage in another activity.

While recreational bikers often stick to the roads, mountain bikers generally prefer to navigate scenic trails and backwoods courses. The mountain bike has been equipped with a shock absorbent suspension for off-road riding. Consider your budget as well as your level of skill before selecting a mountain bike.

The major difference between anaerobic and aerobic conditions is the requirement of oxygen. Anaerobic processes do not require oxygen while aerobic processes do require oxygen. The Krebs cycle, however, is not that simple. It is a part of a complex multi-step process called cellular respiration.

Cyclocross racing was developed to help keep road riders in shape during the off-season. It is an intense event that requires both cross-country and road-riding skills, and helps to hone your riding technique.

Muscle Activation Therapy is an alternative injury recovery strategy.

Cycling instructor certification allows you to teach indoor cycling courses. In an indoor cycling course, the instructor leads participants in a visual journey, often imitating valleys, hills, straight-aways and finish lines. Indoor cycling is an aerobic-type workout.

A spinning reel hangs on the bottom of the rod and the axis of the spool is aligned with the rod. These are sometimes referred to as "open face" spinning reels. Most spincast reels sit on top of the rod but are enclosed(closed face)...the line comes out the front through a small opening.