FAIL: Being a Weekend Warrior We know work and family can limit gym time to   Saturday and Sundays. But, if you only workout on weekends, you put yourself   at a greater risk of injury. Often women will want to take advantage of the   time they have and will go all-out on weekends after doing no exercise or training   all week. This can contribute to shoulder, elbow and even back injuries that   can worsen and progress over time.

FAIL: Reading While Doing Cardio Studies have found that listening to music   while working out can inspire you to work harder. But reading requires more   focus, which takes away from the intensity of your workout. Rarely can someone   maintain sufficient intensity of cardiovascular activity -- even on a stationary   cycle -- while reading. Long, slow cardio may be recommended for novices or   for athletes working in a low-intensity phase of training that is before or   after an event (such as a marathon) but if it's fat and calorie-burning you   want, put down the book. You want to focus on your activity.

FAIL: Rushing Your Reps It’s tempting to try and get through your reps at lightening   speed. But you'll get better results if you dial it down a bit. Referred to   as "time under tension," the amount of time it takes for you to complete your   repetitions plays a role in building "tone. Using momentum by speeding through   your reps also increases your chances of injury and decreases effectiveness.   For strength and tone, a two-second count on the concentric phase (contraction   of the muscle) and a four to five second count for the eccentric (lengthening   or stretching phase) of each move.

FAIL: Walking with Hand Weights If you're holding on to three to five pounds   weights when you walk because you think it burns more calories, you may want   to try picking up the pace instead. Walking with hand weights has been shown   to increase cardiovascular demand in terms of blood pressure and oxygen consumption,   but it's not yet determined if this translates to substantial calorie burning   compared to not carrying the weights. Even if it does, you would have to walk   long and fast for it to make a difference over time. If you're carrying weights   to tone your arms as you walk, the amount of weight you're able to safely hold   on to while walking is likely not causing enough resistance to result in a change   in the muscle (e.g. toning).

FAIL: Bouncing When Stretching In an effort to get a better stretch, you may   be tempted to "bounce" your way into a certain position. Problem is, this "ballistic   stretching" tactic actually backfires. A complex mechanism within the muscle   contains a built-in safety feature that detects the bouncing and reacts by contracting.   It does this to protect the muscle from becoming overstretched. When you rapidly   stretch the muscles by bouncing, the muscle spindles send a message to the spinal   chord telling the muscle to tighten up. This then causes 'microtears' within   the muscle itself. Too much bouncing may actually lead to torn muscles.

FAIL: Channeling Jane Fonda Remember big hair and leg warmers? If you do, you   likely also remember aerobic class moves like the hydrants, leg lifts and side   bends. Some are tried and true, others are potentially dangerous or, at best,   useless. Many were based on the spot reduction theory, where women believe they   can reduce a specific area on their body simply by working that muscle, which   simply isn't true. Other moves are performed so fast they don't allow enough   time under tension to produce strength results and may even be fast enough to   injure the hip joint. Your best bet? Update your workout and leave the Flash   Dance moves in the 80s.

FAIL: You Skip Your Warm Up and Cool Down. Saving time by skipping your warm   up and cool down may leave you hurting. The purpose of the warm up is to get   the core temperature up, to get blood flowing to the muscles, to lubricate joints   and to get mentally prepared for your activity. The cool down helps your cardiovascular   system and central nervous system regain homeostasis (its pre-exercise stable   state), therefore preventing injury. If you don't have time to do a full-blown   warm up, simply beginning your activity very slowly.

FAIL: You Have No Plan If your workout plan varies according to the available   machines at the gym, you're not working out efficiently. An individual cannot   jump from machine to machine each workout without considering safety, effectiveness   and efficiency. Without a set routine the person may be focusing upon the same   body part(s) without cross training other muscles. If you are winging it every   time you go to the gym, you also probably don’t know the machines well enough   to know what weight or seat/equipment height you need to achieve the most efficient   and safe results. Take the time to cultivate and understand your routine. Consistency   is key for setting and achieving goals and commitment.