Practical Guide to Hip and Knee Strengthening

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Progressive Overload for Strength Development

General principles to consider with progressive overload:

• Remember TWO things when dealing with a patient who requires strengthening:
  • Establish the level of load they can currently cope with
  • Keep reassessing the situation as patient progresses
• Progressively expose an individual to load at a tissue and system level
• Maximum tolerated loads are necessary to generate supraphysiological stress and low level of micro failure to create adaptation
• Allow sufficient recovery time to enable adaptation
• Application of the appropriate load to drive the required adaptation
• Specific Adaptation to Imposed Demand (SAID) principle
  • Adaptations produced by training are highly specific to the nature of the stimulus or overload applied
  • Adaptations are specific to strength, power, endurance, functional activity, joint angle, sequence of muscle activations, energy systems and virtually all other variables present
  • SAID principle is impacted by:
    • Position or length of the muscle (length-tension relationship)
    • Speed of contraction (force - velocity relationship)
    • Muscle contraction type (isometric, concentric, eccentric)
    • Percentage (%) repetition maximum
      • Training as a percentage of repetition maximum (RM)
        • e.g. 80% 1RM
      • Repetitions to failure
        • e.g. 80% 1RM = 7 - 10 repetitions to failure

Modified Daily Adjustable Progressive Resistance Exercise (DAPRE) System

• System introduced by Knight (ref)
• 5 RM TO 7 RM 4-set system
• System allows patients to train at fullest potential while still accounting for variations in strength levels
• Sets 1 and 2 are warm-up sets, sets 3 and 4 are maximum effort sets
• Sets are designed around a "working weight"
• The working weight is the weight used in set 3
• Weights used for sets 1 and 2 is a percentage of the working weight (set 1 uses 50% of the working weight, set 2 uses 75% of working weight, set 3 uses the full working weight)
• maximum repetitions performed in set 3 determines the weight to be used in set 4
• number of repetitions performed in set 4 is used to determine the working weight for the next training session
• this system is ideal for rehabilitation, regardless of the degree of the patient's strength or deconditioning
• Recommended article to read: The Daily Adjustable Progressive Resistance Exercise System: Getting Reacquainted With an Old Friend

Table 1. DAPRE System

Set	Weight	Number of repetitions
1	50% of working weight	10
2	75 % of working weight	6
3	working weight	max
4	adjusted working weight	max

Table 2. Guidelines for modification of working weight in DAPRE system

Number of repetitions performed during set 3	Set 4	Next session
0 - 2	decrease 2.5 - 5 kg (5 - 10 lbp)	decrease 2.5 - 5 kg (5 - 10 lbp)
3 - 4	decrease 2.5 kg (5 lbp)	keep the same
5 -6	keep the same	increase 2.5 - 5 kg (5 - 10 lbp)
7 -10	increase 2.5 - 5 kg (5 - 10 lbp)	increase 2.5 - 7.5 kg (5 - 15 lbp)
more than 11	increase 5 - 7.5 kg (10 - 15 lbp)	increase 5 - 10 kg (10 - 20 lbp)

Isolated Muscle Work Around 4 Muscle Groups

• Isolated muscle work presented as the amount of electromyographic (EMG) activity. It is important to know that for strengthening purposes the level of EMG activity needs to be greater than 70 - 80% of an individual's maximum isometric voluntary contraction (MIVC).
• Repetition to failure of a selected exercise needs to be between 8 -10 repetitions for strength training

Gluteus Maximus

Table 3 shows examples of exercises for gluteus maximus recruitment. The percentage maximum isometric voluntary contraction (MIVC) is shown to indicate rank order for these exercises.

Table 3. Rank order of exercises for recruitment of gluteus maximus based on EMG

Exercise	% MIVC
Front plank with hip extended	100
Single leg squat	72
Side plank (average of side plank dominant leg up and side plank dominant leg down)	71
Lateral step up	64
Single leg deadlift	59
Forward step-up	55
Single leg bridge	54
Hip clam	53

Below are some examples of exercises targeting gluteus maximus.

Progression of Bridging Exercise

The four videos below provide an example of progressing the bridge exercise. Performing a unilateral bridge with the other leg straight (lengthened lever arm) produces significantly greater EMG activity than a unilateral bridge with the other leg in 90 degrees hip flexion and 90 degrees knee flexion (shortened lever arm) in gluteus maximus and gluteus medius. Lecheka The addition of a band to the exercise further increases gluteal activity. (Forman 2023)

In patients who are not able to tolerate a high amount of load very well (e.g. a patient with spinal problems), consider a hip thrust type of exercise with a weight across the pelvis instead of a squat or split squat exercise. See two examples of exercises below.

Gluteus medius

Table 4 shows the rank order of exercises for recruitment of gluteus medius based on EMG activity.

Table 4. Rank order of exercises for gluteus medius recruitment based on EMG activity

Exercise	%MIVC
Side plank	100
Single leg squat	82
Front plank hip extended	75
Lateral step up	64
Hip abduction in sidelying	63
Single leg deadlift	56
Forward step-up	55
Single leg bridge	55
Hip Clam	47

Below are some examples of exercises targeting gluteus medius:

Recommended reading:

• Electromyographic analysis of gluteus medius and gluteus maximus during rehabilitation exercises.
  • This article provides a list of exercises and the percentage MIVC of the gluteal muscles that occurs during these various exercises. Images and instructions of all exercises are also provided.
• Gluteal Muscle Forces during Hip-Focused Injury Prevention and Rehabilitation Exercises(restricted access)
  • Muscles forces in eight hip-focused exercises were compared and ranked. The exercises were performed with and without external resistance. Underlying fibre lengths, velocities and muscle activations were described by inputting data from motion capture, ground reaction forces and EMG into an EMG-informed neuromusculoskeletal model. Gluteus maximus, medius and minimus muscle forces were estimated in this model.
  • Tier 1 exercises for Gluteus maximus were: loaded split squat, loaded single leg romanian deadlift, loaded single leg hip thrust
  • Tier 1 exercises for Gluteus medius were: Body weight side plank, loaded single leg squat, loaded single leg Romanian deadlift
  • Tier 1 exercises for Gluteus minimus were: loaded single leg Romanian deadlift, body weight side plank
  • Blog post to read: Hip-focused injury prevention and rehabilitation exercises: How to choose which one?
  • Useful infographic: Gluteal muscle forces during hip-focused injury prevention and rehabilitation exercises

Hip Adductors

The rank order of exercises for the recruitment of adductor longus based on EMG is shown in Table 5. The mean peak normalised EMG (nEMG) results of a maximum voluntary contraction (MVC) of the adductor longus of the dominant leg are shown. Note in the study by Serner et al. the dominant leg was defined as the preferred kicking leg.

Table 5. Rank order of exercises for adductor longus recruitment based on EMG activity (adapted from Serner et al)

Exercise	Mean peak normalised EMG (nEMG) of MVC of the dominant leg (side of the preferred kicking leg) (%)
Isometric adduction with ball between knees	108 ± 6
Copenhagen adduction	108 ± 5
Hip adduction with band	103 ± 6
Hip adductor machine	99 ± 6
Sliding hip abduction / adduction	98 ± 6
Isometric adduction with a ball between ankles	86 ± 6
Hip adduction sidelying	64 ± 6
Hip adduction supine	14 ± 6

Below are examples of some of the adductor exercises.

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