Exercises
Exercises
Hack Squats
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Historical reference: its only source is the original reference manual, and some of it may be out of date. Not used for AI answers until re-sourced.
See this lesson’s sourcesquadricepscompoundmachinelower-body
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Exercise demo
In one line
Machine hack squat emphasizing vastus lateralis and intermedius plus the adductors; intermediate quad exercise.
Detail
A machine squat variation (TK Hack). The source notes a hack squat at 30 degrees in relation to the hip-knee relationship. Listed as an intermediate-level quadriceps selection (M = machine).
Key facts
- Primary Muscles: Vastus Lateralis, Vastus Intermedius, Adductor Brevis, Adductor Magnus.
- Secondary Muscles: Vastus Medialis, Sartorius, Gracilis, Gluteus Maximus.
- Machine exercise; ~30-degree angle noted.
Connections
- Quadriceps — quad emphasis.
- Hip Adductors — adductor brevis/magnus primary here.
- Sartorius / Gracilis — secondary.
- Gluteus Maximus — secondary hip extensor.
- Squats — related compound exercise.
Sources
Historical reference · reference manual (page cited)
p.104p.364p.492p.688
Cited authorities in source: none specified for this entry.
Exercise guides
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Atlas Connections
Gluteus Maximus
The strongest, largest muscle in the body; the primary hip extensor and a lateral rotator of the femur.Gracilis
The only 2-joint hip adductor; a weak adductor and knee flexor that the body can do without.Hip Adductors
The hip adductors are the pectineus, adductor brevis, adductor longus, adductor magnus, and gracilis.Hip Joint Range of Motion
Hip flexion 90° (knee extended) to 120° (up to 135°, knee flexed); hyperextension 10–30°; adduction 30°; abduction 45°; medial rotation 30–45°; lateral rotation 45–60°.Knee Joint Range of Motion
The knee is a hinge joint that straightens to about 0° and, in healthy adults, bends to roughly 133–142° depending on age and sex (CDC reference data). The "90°" often quoted is the arc of a seated leg extension, not the knee's full range.Quadriceps
The four knee extensors — rectus femoris, vastus medialis, vastus lateralis, vastus intermedius (rectus femoris also flexes the hip); the leg-extension arc is ~90° (knee bent to straight).Sartorius
The longest muscle in the body; a 2-joint hip flexor and adductor that also flexes and laterally rotates the knee.SquatsClosely related
The squat is the main multi-joint lower-body lift. The knees and hips extend together, driven by the three vasti, the glutes and the adductors. Squat to at least thighs-parallel, deeper if you control it with a braced trunk and heels down, and let your knees travel forward over your toes as they naturally do.Intensity
The amount of weight (resistance) lifted — also shaped by speed, reps, sets, rest interval, and workout duration.Deep Knee Bend / Lunge / Squat — Contraindicated Ballistic Stretch
Bouncing or forcing into deep knee bends, lunges, or squats as a stretch is marked "X" in the source (said to strain the knee's lateral ligaments, compress the kneecap, and pinch cartilage). This is about ballistic end-range stretching, not controlled deep squats, which are safe for healthy knees.