If one is to buy just 1 machine (reasonably affordable), what would be the best choice that works well? I'd like to cover - 1. Cardiovascular 2. Legs (of course, for badminton) 3. Upper body (like abdomen, arms, back) - Nice to have, but not too high in priority 4. Work on multiple aspects at the same time 5. Compact - won't occupy too much space at home 6. Won't lead to injuries easily What comes to mind are 1. Treadmill - though I heard it could injure the feet 2. Eliptical trainer 3. Stair-master 4. Total Gym Comments/recommendations?
one machine probably cannot do all. but you can do without a lot of machinery. - cardio / calf strength / wrist agility - jump rope $20 - upper body - pull-up / chin-up / leg raise. my co-worker has one of this in his cube: http://www.amazon.com/Body-Vision-PT600-Power-Tower/dp/B000M29CCI/ref=sr_1_5?ie=UTF8&qid=1318733770&sr=8-5 - leg strength: barbell set. probably $100-ish. for squats, etc. total should be less than $250.
if you have room, free weights are your best choices. you can work your upper body (arm, chest, back...) and lower body (lunges, squats, toe tips...) and core based on different workouts and routines for both power and stemina. the thing with any workout machine is that they can be expensive, limited routines (at best 5-6), and bulky/heavy. but if you insist on a machine, take a look at "bow-flex". their equipment seem pretty intriguing
i would put more focus on abdominal muscles and back exercises than you seem to suggest is necessary. I am not expert on equipment and such, as I do all my training with very limited equipment, but the core muscles are of vital importance, mainly to prevent injury, but it also helps with power generation, endurance, co-ordination etc. I hope you find what you want!
A rowing machine? Arms pull the bar through, legs extend and push you back, core muscles are involved to keep posture and it's a really good cardio workout. A few little additions to the machine can allow wide grip rows for increased emphasis on the chest. They are small and can be stored vertically hidden in a corner. Treadmills can damage your feet, but so can running outdoor. The best way to avoid an injury while using a treadmill is to run at an incline of 1.5 and this reduces the impact on your knees.