When it comes to building beefy hamstrings, your rep range matters. For size, do both a heavy load, lower-rep range and a higher rep range.

First, your hamstrings are primarily fast-twitch dominant. Anecdotally, this may contribute to the massive hamstring development in sprint athletes. In the gym, this means you should incorporate heavy, explosive, and/or low-rep training.

Second, as with all muscles, a longer time under tension increases metabolic stress, which is a primary factor in muscle growth. Given you can create sufficient tension in a muscle, higher rep sets and a longer time under tension will help you grow any lagging muscle group, hamstrings included.

A study published in the Journal of Strength and Conditioning Research makes a compelling argument for a mix-and-match approach. Japanese researchers had a group of male lifters do conventional hypertrophy training for six weeks before dividing them into two groups. Some did typical strength work – five sets of each exercise, using 90% of their 1RM. The others did the same thing, plus a final set of 25 to 35 reps using 40 to 50% of their 1RM.

The second group made slightly better gains in size over the next four weeks. Not a huge surprise because, hey, a tack-on burnout set is hardly ever going to put your gains in the ground. But the big surprise is that the second group made bigger increases in strength as well.

This study suggests a compelling take-away message: Those light weight, high-rep sets following heavy weight, low-rep sets will make your hams stronger—and the stronger they get, the more effective high-rep training becomes.

Accentuated means "emphasized." And eccentric is the "lowering phase" or the "negative" of the lift. Many lifters miss out on the benefits of eccentric overload or a lack of time under tension during the eccentric. As a result, they never maximize muscular development.

The battle? First, accentuated eccentrics are brutally hard work. Take the accentuated eccentric on the trap bar deadlift below:

Second, they can be extraordinarily taxing on your central nervous system. You'll need to dial back in other areas of training OR increase your emphasis on recovery. Luckily, with a well-designed program (provided below) we can mitigate many of those issues.

To reduce joint stress and CNS fatigue, you can use machine-based eccentric training with 2:1 accentuated eccentric. With hamstring curls, you'll use both legs to curl the load and only one leg to lower the weight back to the starting position. This requires you to focus on the eccentric tempo to maximize muscle building tension to shock your hamstrings into growing.

Here's why this works:

• The explosive concentric/lifting movement improves muscle fiber recruitment. With a greater number of muscle fibers stimulated, your potential for muscle growth increases.
• The slow eccentric/negative action increases mechanical tension, metabolic stress, and fatigues a greater number of muscle fibers. And since the muscle is under tension for longer, blood can't enter it, creating a hypoxic environment. This boosts metabolic stress and increases growth factors like IGF-1, further boosting muscle gains.
• Using one limb to lower the weight boosts the eccentric load on the working limb by 50%, creating more tension and hitting a high number of muscle fibers.

Here's what the seated and lying variations look like:

Not only do these exercises improve your mind-muscle connection (the proven mind-hack for muscle growth according to the greatest bodybuilders of our time) but they also increase time under tension – lowering your legs in a slow and controlled manner on the eccentric phase of every rep. By recruiting a high amount of muscle fibers and then maximizing fatigue of those muscle fibers, you've got a winning recipe for growth.

Do the 2:1 technique at the end of training for 3-4 sets of 4-8 reps. The lifting action should be explosive and the lowering action should take about 5 seconds. I don't recommend that you use this technique every day. Instead, pick one or two areas of focus for a month, then switch.

Pre-stimulation exercise is a standard warm-up for your hamstrings. It gets your mind tuned in to your hams during your working sets, which will improve growth.

Think about this: Have you ever felt your shoulders or triceps during a bench press? Or have you ever felt your biceps screaming "Uncle!" during a set of pull-ups? Both are classic cases of poor mind-muscle connection and poor muscle fiber recruitment in target muscles.

In order to fix the miscommunication between your mind and hamstrings, use pre-stimulating movements before compound movements. They'll improve muscle fiber recruitment in your hams before you use them with compound exercises, paving the way for explosive new growth.

And remember, the goal of pre-stimulation isn't pre-exhaustion. There's no need to tire out your hamstrings before the "big-boy" lifts. But if you want to put some meat on your backside, pre-stimulation is key. Examples of pre-stimulation:

• Perform 45-degree banded back extensions before you squat. The goal is to pump the glutes, hamstrings, and erectors to improve the stability of the knee and enhance the mind-muscle connection in your posterior chain.




• Do leg curls before you deadlift. You'll stimulate the mind-muscle connection with your hamstrings and improve your ability to rely on your hamstrings for a bigger deadlift.

According to a groundbreaking study published in PLOS ONE, the more often you train a muscle, the more you increase protein synthesis towards that muscle... leading to more muscle growth every time (1).

Muscle protein synthesis (MPS) is the fundamental biological process by which cells build their specific proteins – and your muscles grow through this process. Studies have shown that protein synthesis lasts for about 24-48 hours after a resistance training bout. So if you want to rapidly grow your hamstrings, training them 2-3 times per week will spike MPS to accelerate muscle growth.

When it comes to building a strong, dense, and athletic physique, nothing improves lower-body development like sprinting. See, when you run sprints, you initiate a massive CNS output, which means you'll activate a ton of muscle fibers to rapidly produce high levels of force. And the more muscle fibers you activate, the more muscle growth you'll get.

But this comes with a warning. Because sprinting is neurologically demanding, it should be done while fresh to prevent hamstring pulls, or submaximally on an incline to prevent overstriding. When combined with a balanced weight room attack, two days of sprinting will be a game changer both for your body composition and hamstring development.

Now that you have the components in place, let's put 'em to good use within the framework of a classic upper-lower training split.

Monday – Lower Body

Tuesday – Treadmill or Incline Hill Sprints

• 5-10 minute dynamic warm-up.
• 2-3 practice sprints at 50-60% speed.
• Treadmill Option: 8 rounds of 30-second sprints (1-minute rest in between)
• Hill Option: 6x sprint uphill, walk back plus one minute recovery.

Wednesday – Upper Body Training

Thursday – Lower Body

Friday Day Four – Upper Body

Saturday – Treadmill or Incline Hill Sprints, Then Bourbon

• 5-10 minute dynamic warm-up.
• 2-3 practice sprints at 50-60% speed.
• Treadmill Option: 8 rounds of 30-second sprints (1-minute rest in between)
• Hill Option: 6x sprint uphill, walk back plus one minute recovery.

Bourbon? Trust me, you'll appreciate the reward.

1. Morton RW et al. Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men. J Appl Physiol (1985). 2016 Jul 1;121(1):129-38. PubMed.
2. Catatayud J et al. Importance of mind-muscle connection during progressive resistance training. Eur J Appl Physiol. 2016 Mar;116(3):527-33. PubMed.
3. Burd NA et al. Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise in Young Men. PLoS One. 2010 Aug 9;5(8):e12033. PubMed