Hi I should have said this comment is directed more to people who don't exercise much and to motivate walking, jogging for the first time.
Your info is good but I still recommend stretching it loosens the muscle to build it back up stronger with exercise, a similar effect is using massage where you break down the muscle and rebuild the strength which releases muscle tension but inevitably makes you stronger. Thanks for your comment :)
Two studies have shown why you don't need to stretch.
One study done by The Journal of Strength and Conditioning Research stated "If you stretch before you lift weights, you may find yourself feeling weaker and wobblier than you expect during your workout" The second study published in The Scandinavian Journal of Medicine and Science in Sports says that exercise stretching is generally unnecessary and likely counterproductive. According to their calculations, "static stretching reduces strength in the stretched muscles by almost 5.5 percent, with the impact increasing in people who hold individual stretches for 90 seconds or more. While the effect is reduced somewhat when people’s stretches last less than 45 seconds, stretched muscles are, in general, substantially less strong".
A better choice is to warm up dynamically, by moving the muscles that will be called upon in your workout.
As for the "no pain no gain" Instead of basing how effective your workouts are by soreness, make use of other proven methods for testing progression. If you wish to increase strength, use the one-rep maximum test. Your one-rep maximum refers to the heaviest amount of weight you can move in an exercise for one repetition. For measuring size gains, perform circumference measurements and record. Various body locations such as the chest, biceps and thighs are indicators of size gains. For weight loss, use a scale and record your weight. Measure your progress every four to six weeks to assess the effectiveness of your workout plan.
My routine is the following,( I only use machines ) I do 6 reps of the maximum weight I can lift perfectly for 6 times then I move the pin to a lighter weight and do 12 reps then move the pin to a lighter weight and do 24 reps.That's 1 set I then rest for 90 seconds and repeat the set two more times with the 90 second rest between each set. The only rest I get during each set is maybe 1-2 seconds of moving the pin in the stack of weight.