Not only is the inverted row one of the most underrated Smith machine lat exercises, it's one of the most underrated back exercises full stop.
Forget the assisted pull up machine, getting strong at bodyweight rows is the gateway to becoming proficient at pull ups.
But even if you can already do a pull up—or ten—you'll be amazed at how the Smith machine inverted row can literally transform your physique. Especially with one small modification...
Here's how to perform the inverted row Smith machine style:
If you want to enjoy the full benefits of the Smith machine body weight row, then it's not enough to merely pull yourself towards the bar—you need to think in terms of muscles.
Since your back muscles are naturally much stronger than your arms—and since the inverted row is primarily a back exercise— it makes sense to engage your lats and traps from the very first inch of movement.
You can do this by actively squeezing your back before beginning the rep and then initiating the actual movement by driving your elbows behind your body. In this regard, your hands are like hooks. And your arms only flex because they happen to connect your body to those hooks.
In other words, your biceps only get stimulated as a consequence of your back stretching and contracting.
Squeeze your glutes to stop your hips from sagging. Letting your hips drop turns the exercise into a poor man's pull up—and it significantly reduces your back activation.
If you didn't pay much attention in school like me, then you've probably already mastered this crucial form tip.
While it's undeniably tempting to turn your head and check out your bicep veins, this kind of neck movement isn't very healthy for your lower back because it often causes your spine to round.
Instead, choose a spot on the ceiling (preferably not the gym lights) and stick to it. You'll feel the exercise more in your traps this way, and your spine will thank you for the break.
Wearing a weighted vest during Smith machine bodyweight rows will take your back from toned and slender to thick and wide. It'll also help to increase your pull up strength.
And you don't need anything fancy. I personally use the Runfast Weighted Vest, and I have no complaints.
The vest is fully adjustable, so it fits my average body size perfectly. I got the 30kg version because I also use it for other exercises like push ups and split squats. However, it's also available in 4 other sizes: 5kg, 10kg, 15kg, and 20kg.
I like that the moisture-wicking material keeps my body cool and dry. Because there's nothing worse than marinating in your own sweat while working out. Especially if you train in a public gym!
If you know anything about me, you'll know that my grip strength was always shocking until I started strengthening it with the Captains of Crush Hand Grippers.
For the longest time, my feeble grip held me back on some of my favourite back-building exercises, like inverted rows and pull ups. And although my grip strength has improved in recent times, I never hit the gym (well, my home gym these days) without my liquid chalk.
I've used this chalk since back in the day when I'd train in public gyms. The staff weren't too fond of me chalking up my hands with my old Psychi Chalk Ball. So I used my liquid chalk on the sly to improve my grip (I know what a rebel).
Anyway, chalk won't make or break your gains; otherwise I'd be Mr Olympia by now. However, it will let you squeeze out a few extra reps on your sets. And it'll probably increase your pulling lifts by a few kilos at least.
If the sun is shining brightly and the rain is at bay (which isn't all too common up north) then sometimes I'll take my gymnastics rings to the park and work out there.
But lately, I've also been experimenting with attaching them to the top of my Smith machine for inverted rows, since the regular version wasn't challenging me anymore. The movement felt really weird at first. But after practising for a few weeks, it's second nature.
I feel more like an athlete rather than a pumped-up bodybuilder when I do ring rows. And the irony is that they probably work my back better than any kind of free weight or machine row.
Plus, a good pair of gymnastics rings are much cheaper than buying a big free weight set. So I definitely recommend the small investment if you're into bodyweight training like me.
While performing inverted rows Smith machine style, you can move your feet closer to the bar to emphasise your lats. You know you're in the right position when the bar is in line with your lower chest.
Push your feet forwards and centre the bar over your mid-chest to emphasise your traps during the Smith machine body row. Also allow your elbows to flare out slightly from your torso, as doing so places the trapezius muscles in a stronger line of pull.
The more you flare your elbows out during any kind of rowing exercise, the more you'll activate your rear and side delts, and the less you'll work your lats. So, since the inverted row is a compound movement, I'm going to recommend that you keep your elbows tucked—45 degrees of elbow flare should do the trick.
This way, all of your muscles receive somewhat equal tension. And as a result, your back will naturally look more symmetrical than if you tried to isolate certain parts of it.
The bicep performs a multitude of functions. However, the main two are forearm supination (turning your palm upwards) and elbow flexion (shortening the distance between your upper and lower arm).
Since inverted rows are always performed with an overhand grip, you won't get any bicep activation via forearm supination. But you will get a decent amount of bicep stimulation from the constant elbow flexion, which is required to pull yourself up.
The brachioradialis is the large muscle that runs down the top of your forearm. And because your biceps are in a relatively weak position during inverted rows, your brachioradialis naturally picks up the slack. So you'll feel it working as you pump out those reps.
The forearm flexors help you to maintain a firm grip on the bar by sending tension down the kinetic chain to your smaller hand muscles. So avoid using lifting straps. Otherwise, these smaller muscles will fall way behind your back in relative development .
That said, I still highly recommend using liquid chalk if you have it available because it'll help you to crank out more reps by preventing your hands from slipping when things get a little sweaty. Just make sure to stick with the liquid variety if you train in a gym that isn't too fond of its members chalking up their hands (and thereby the equipment).
In the same way that press ups are regarded as a safer chest exercise then bench presses, inverted rows are widely considered more joint-friendly than barbell rows.
This is simply because bodyweight exercises have a closed kinetic chain (you dictate the range of motion). In contrast, free weight exercises have an open kinetic chain (the machine dictates the range of motion). 
When you can move your joints freely, you naturally activate more stabiliser muscles than when you're forced to move them through a fixed range of motion. Of course, this unrestricted movement keeps your joints healthy because your muscles don't have any weak links (which is usually the rotator cuffs, in the case of the upper body).
Don't be that person who can barbell row their bodyweight for 10 reps, yet can't even do a single inverted row or pull up. After all, what's the point in being muscular if you can't use that muscle for anything other than flexing in the mirror?
Bulging biceps are a dime a dozen—they don't turn heads in the gym anymore. But performing muscle-ups for reps? Now that's a different story .
Plus, mastering your bodyweight is deeply satisfying.
If I had to guess which exercise builds more muscle mass—inverted rows or barbell rows—I'd go with the Smith machine bodyweight row. Why?
Because bodyweight exercises require a higher degree of stabilisation. As any EMG study will show you, major muscles tend to become more active when you have to use surrounding muscles to stabilise them.
This is why weighted inverted rows are such a crucial part of my workout routine. I get to build a wide, thick back while simultaneously developing epic bodyweight strength and keeping my joints healthy. What's not to love? 
The Smith machine barbell row is a brilliant exercise if your goals are purely bodybuilding-driven. Unlike with regular barbell rows, you don't have to stabilise the weight or deadlift the bar up before every set. As a result, you can build muscle faster (at least in theory) by focusing 100% of your attention on hammering your lats and traps.
The reverse grip Smith machine row is the exact opposite of the exercise that I just spoke about. Rather than emphasising your traps and rear delts, the underhand version shifts the tension onto your lats and biceps, allowing you to stimulate yet more back growth by lifting heavier weight.
Plus, it was a favourite of six-time Mr Olympin Dorian Yates. Need I say more?
If you've got muscle imbalances in your back (and I think most of us do), then I recommend adding the single-arm Smith machine row (or a close variation) into your routine. Like a dumbbell row, this unilateral back builder enables you to create a more proportional v-taper by working each side of your body independently, ensuring that both of your lats receive equal work.
It's a great complement to a bodyweight exercise like the Smith machine inverted row.