Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to stretch your quads (quadriceps ) [title] Walk or bike for 10 to 15 minutes. [step] A gentle cardio exercise such as walking or biking will get the blood flowing to your quads and make stretching more comfortable. Stretching cold muscles could result in injury.

Ending1: [substeps] Walking can also prevent an injury, which may recur with your workout. If you find yourself with sore muscles, be sure to drink plenty of water before and after your workout. Ending2: [substeps] For white or light runners, consider lowering your speed to 15 or 30 mph (60 to 90 km/h). For black or light runners, start running at a moderate pace, about 70-80 mph (35-52 km/h). Ending3: [substeps] If you're planning on exercising outside in cooler weather, add 5 to 10 minutes to your warm-up time before you start stretching. [title] Do standing quad stretches before a long run. Ending4: [substeps] If the tightness in your quads is significant enough to warrant good stretching, you could walk for 10 to 15 minutes, as long as the muscles aren't too tight or hard. [title] Have a partner hold onto your legs to stretch them.

Answer format: ending1/ending2/ending3/ending4