I did some digging and we almost forgot about the original Hack Squat
Biomechanics — why it works
Inputs: bar behind the heels, more vertical torso, knee-forward travel.
Levers change: center of mass shifts forward relative to hips and closer to the knee joint. That raises knee extension moment and lowers hip extension and spinal shear moments compared with a back squat for a given load. That emphasizes quadriceps and reduces hamstrings/erector spinae demand. The general squat biomechanics review explains how bar position and torso angle determine hip vs knee moments.
PMC
Muscle activation evidence
EMG and kinematic studies show hack-squat style setups produce higher knee-centric work and lower erector-spinae and hamstring activity than many other squat forms. That makes it effective for quad development and for trainees who need lower back unloading. (Specific studies comparing squat variations back this pattern.)
ResearchGate
Use it when you want:
• quad hypertrophy with less low-back stress.
• a variation for people with limited hip mobility or torso control.
• rehab or accessory work focusing knee strength and stabilization.
It is not universally superior because:
• it reduces hip/glute loading compared with back and low-bar squats.
• it demands good knee tracking and can increase patellofemoral stress if performed poorly.
• it transfers less directly to athletic tasks that depend on hip extension (sprinting, heavy deadlift).
How to perform the original barbell Hack Squat (correctly)
Bar on floor behind heels. Stand feet hip-to-shoulder width. Toes can point slightly out.
Hinge slightly at hips and reach back to grip bar behind legs (mixed grip or double over). Keep chest up.
Take a full breath and brace core.
Unrack by extending hips and knees to standing while keeping the bar close behind the calves. Torso stays more upright than a back squat.
Descend under control to full depth (thighs below parallel if mobility allows). Knees track toes. Maintain neutral spine.
Drive through midfoot to stand. Do not hyperextend the low back at lockout. Progress load conservatively.
Breaking Muscle
George Hackenschmidt’s The Way to Live (1908), focusing only on his actual exercise prescriptions, sets, reps, and progressions:
Hackenschmidt Training Manual (Condensed)
General Rules
Train daily if possible, but 3–4 times weekly minimum.
Start with light weights; progress weekly by small increments.
Perform all movements slowly and under control.
Breathe deeply, never hold breath excessively.
Strive for full range of motion in every lift.
Bodyweight / Free Exercises
Warm-up drills: arm swings, deep breathing, skipping, mobility.
Squats (free, no weight): begin with 10–15 reps, progress to 20–30.
Floor work: push-ups, sit-ups, leg raises (same rep ranges).
Weighted Exercises
Leg Specialization
Hacke (Hack Squat)
Barbell held behind back, heels together, squat deeply on toes.
Start: 5–10 reps.
Progress: add weight each week, aim for 20 reps continuous.
Hackenschmidt: called it one of the best leg exercises in the world.
Front-loaded Squat (bar in front of chest/shoulders)
Start: 5–10 reps.
Goal: up to 20 continuous reps with moderate load.
Skipping / jumps / hop-step-jump drills for spring and endurance.
Back and Hips
Deadlift
Lift barbell from floor with straight arms.
Begin: 5–8 reps.
Increase load gradually.
Good Morning (barbell across shoulders, bend forward)
Start: 5–10 reps.
Hip raises / bridging drills for glutes and core.
Shoulders and Chest
Overhead Press (barbell or dumbbells)
Begin: 5 reps, work toward 10–12.
Add weight weekly.
Bench press / floor press (called “pressing while lying”)
Same progression as overhead.
Dumbbell laterals and raises for shoulder isolation.
Arms
Biceps curl (dumbbell or barbell)
6–10 reps.
Controlled motion, full extension each rep.
Triceps press / overhead extension
5–8 reps.
Abdomen
Weighted sit-ups: 10–20 reps.
Leg raises: 10–20 reps.
Twists and side bends for obliques.
Progression Scheme
Week 1: Choose a light weight you can handle with ease.
Each week: Add a “very small” increment (Hackenschmidt stressed patience).
Target: After 2–3 months, weights should feel “astonishingly light” compared to start.
Rule: Never rush; safety and form above all.
Lifestyle Reinforcement
Sleep 7–9 hours, fresh air, sun, and balanced food.
Avoid stimulants, heavy alcohol, or overeating.
Train both strength and vitality (circulation, lungs, endurance).
This condensed version extracts the actual sets, reps, and methods from the text.