My Gym has no Squat rack so I have to do the squats with lower weights. I'm following a classic PPL program and my 5 rep maxes are:
BP: 65kgx5
DL: 100kgx5
OHP: 45kgx5
Bent Over Row: 60kgx5
Squat: 75kgx5 :(
I'm going to try using Smith-machine for squat, do you think is it a good solution? Or should I start doing Leg-press instead?
I would try and avoid smith machine squats for the time being. They take away a lot of the supporting strength from traditional barbell squats, and lock you into a very linear movement (i.e. up and down).
I'd also avoid the leg press as your main lower body movement, as it doesn't involve the spinal erectors as traditional squats do.
Instead, you could consider:
A few years back Mike Boyle famously (infamously?) stopped his athletes squatting and instead concentrated on Bulgarian split squats (aka rear foot elevated split squats).
Dan John has written extensively about the benefits of goblet squats, if you think they're easy, grab a 50kg dumbbell and knock out a few sets of 20 reps.
Lunges, although occasionally given a bad rap as something 80's lycra clad aerobics class attendees would do, are an amazing strengthening exercise. Again, if you think they're easy, grab a couple of 30kg dumbbells and do walking lunges the length of your gym. Then turn round and do the same back.
Pistol squats, overhead squats and step ups I'd put more as accessory work / assistance lifts, but they're still very useful and valid squat alternatives (pistols can be difficult to load, overhead squats can be quite technically complex and step ups require something sturdy to step up onto).
Front squats from a clean (because you don't have a squat rack) are a possibility, but there is a significant learning curve to the clean movement, meaning that other options may be better for basic strength training.
The smith machine is not a substitute for a squat rack, unfortunately. If you have no way of getting the bar onto your shoulders, you might be better off doing Goblet Squats instead, either with a kettlebell, or dumbbell.
Then, you could supplement that with leg press, to get the more heavy stimulus.
The Smith Machine isn't ideal, but in your circumstance, it's better than nothing. I think it is more important to do the movement safely since you don't have a rack to accommodate using heavy weight. You will still get leg, hip and back work unlike leg presses and leg extension/curls alone.
Supplement it with other alternative leg exercises with some emphasis on free movement alternative, lunges, front squats, etc. This will help with core and athletic movements requiring balance.
That is a real bummer that the gym doesn't have a power rack. I'm not sure that it could be called a "real" gym if it doesn't have one.
On a serious note, are you able to find a gym that does have a power rack?
Performing a real squat is about the best single exercise you can do. When it comes to single exercises, a barbell squat is the king, and the deadlift is the queen.
I guess a Smith Machine is okay if that is the only thing, but it still pales in comparison to the real squat. First off, the Smith Machine, is exactly that, a machine; so it moves in an unnatural movement path. Secondly, a real squat activates up to 43% more muscle fiber compared to Smith Machine, all other things being equal.
A leg press, depending on its configuration isn't a suitable replacement for a real squat either. This might be opinion to some, but a leg press doesn't garner the same hormonal response (test and growth hormone) than a deep barbell squat. Further, your lower back (lumbar) can be put into a compromising position (rounding), and that gets worse as the weight starts to get really heavy (rounding and compression).
A side note: Check out the book Starting Strength or very similar program, StrongLifts.com
I'm not really a fan of them, but I've resorted to the hack squat a couple of times when the power cages are mobbed. It's a good lift to know even if you don't do it a lot.
My real go-to for gyms lacking squat racks or when they're full however is the clean. You get a front squat out of if when you catch it low, and you get all the benefits of the clean. The only problem is that they're tricky to learn and having bumper plates while not required is really helpful.
Otherwise I'd focus on some of the other great answers in this thread already. Lunges in particular.
Regarding the smith machine, it's just bad for you (references included). It's a good place to hang your towel but otherwise avoid it.
