Theme 2

Question 1

Why does the trade-off between force and velocity occur?

Answer 1

With increased velocity, the time available for cross-bridges to be formed decreases meaning there is a reduction in contractile force.

Question 2

In most cases, what is the objective of strength and power training?

Answer 2

To shift the F-V curve to the right making the athlete more explosive by increasing their RFD.
If you only train one part of the curve it is likely you will only improve performance in that section, and reduce it in others.

Question 3

Maximal strength - what is it? Exercise examples.

Answer 3

The maximum amount of force someone is able to produce through a specific movement, > 90% 1RM.
1RM back squat, deadlift etc.

Question 4

Strength-speed - what is it? Example exercises?

Answer 4

Exercises that don’t achieve peak power or force. Leans more towards strength.
80-90% 1RM.
Snatch, clean and jerk.

Question 5

Peak power. What is it? Exercise examples.

Answer 5

The greatest amount of force produced in the least amount of time.
30-80% 1RM.
Moderate load jump squats, bench press throw.

Question 6

Speed-strength. What is it? Example exercises.

Answer 6

Higher movement velocities than strength-speed, but still not peak power or peak velocity. Leans more towards speed.
30-60% 1RM.
Slow stretch-shortening cycle plyometric drills e.g. CMJ, light load squat jumps.

Question 7

Maximal velocity. What is it? Example exercises

Answer 7

Maximum movement velocity or muscle contractile velocity an athlete is able to produce through a specific movement.
< 30% 1RM.
Fast stretch shortening plyometric drills such as hopping, sprinting and assisted sprinting.

Question 8

What is validity in relation to the IKD?

Answer 8

The degree to which the test accurately measures what it is intended to measure e.g. muscle strength, endurance, fatigue or power.

Question 9

Give four IKD validity issues.

Answer 9

Lack of functional relevance
Motivation issues
Familiarisation issues
Differences between angular velocities

Question 10

Why can IKD tests lack functional relevance?

Answer 10

The IKD isolates specific joints and muscle groups in a single, controlled plane of motion. This does not reflect real-world sporting actions which often involve:
1. multi-joint, multi-planar coordination,
2. rapid, reactive force production
3. balance, proprioception and motor control.
This means that high performance on the IKD may not translate to on-field success or functional movement capacity. `

Question 11

What is a solution for the lack of functional relevance in IKD testing?

Answer 11

Use alongside functional testing which helps to determine whether improvements in isolated strength carry over to performance.
E.G. a footballer might show high quadriceps torque but lack sprinting power due to poor glute/hamstring contribution, limited hip extension strength, inefficient sprint mechanics or coordination.

Question 12

What functional tests can assess performance as a solution to the lack of functional relevance of IKD?

Answer 12

Strength - 1RM squat
power - sprint time, vertical jump, power clean
Endurance - repeated sprints, yo-yo test

Question 13

One issue with IKD is its lack of functional relevance, what protocols does this apply most to? Why?

Answer 13

Strength and power, but is broad.
These are isolated on the IKD but real-world performance depends on multiple joints and coordination.

Question 14

What type of validity issue is a motivation issue?

Answer 14

Internal validity - the extent to which a test can demonstrate a cause and effect relationship.
Does the test actually measure fatigue or is it loss of motivation or lack of endurance etc?

Question 15

What protocols is a lack of motivation most relevant to? Why?

Answer 15

Fatigue and endurance.
These protocols involve multiple or sustained effort, so inconsistent motivation or pain has a larger impact on output.

Question 16

Why is a lack of motivation an issue in IKD testing?

Answer 16

Motivation, pain and fatigue affect performance by leading to submaximal effort, compromising accuracy.
If a participant is tired etc, their torque output will be lower leading to underestimation of true strength/endurance, inaccurate comparisons between limbs or sessions, poor reliability in tracking progress over time.

Question 17

What is a solution to issues with motivation, pain and fatigue?

Answer 17

Standardise testing conditions.
Allow adequate recovery time between trials to reduce fatigue, especially when not the target variable. E.g. in a strength protocol give 60-90 seconds rest between maximal effort reps.
Control verbal encouragement - use the same intensity, timing and phrasing across all trials and for all participants. Particularly important in endurance or fatigue protocols.
Address pain/discomfort before testing - ensure participants are physically ready, as pain will naturally inhibit muscular contraction.
Use familiarisation sessions - reduced anxiety or uncertainty and helps to establish consistent effort across sessions.

Question 18

Which protocol is the the familiarity effect most likely to affect? Why?

Answer 18

Strength, power, RFD.
These rely on maximal, explosive efforts, so unfamiliarity can prevent participants from reaching true peak output on early trials.

Question 19

Why is the familiarity effect an issue with IKD testing?

Answer 19

Performance during initial trials may be artificially low due to a lack of familiarity with the IKD machine, movement pattern or testing procedure.
Inaccurate baseline measurements.
Learning or adaptation can falsely appear as improvements.
Reduced repeatability of the test especially across sessions.

Question 20

What is a solution to the familiarisation effect issue?

Answer 20

Include a familiarisation phase e.g. practice trial or session before actual data collection e.g. a few submaximal and a few maximal reps.
Standardise the familiarisation procedure, same number instructions and protocol for all participants.
Allow sufficient rest after the trial.
Potentially the need to conduct on a completely separate testing day especially in research/elite sport where high data accuracy is required.

Question 21

What type of validity issue is a lack of functional relevance?

Answer 21

Ecological validity.

Question 22

Why do differences between angular velocities affect validity in IKD testing?

Answer 22

Differing speeds will yield different force outputs, affecting how results are interpreted or compared.
Torque is typically higher as slower speeds. Comparing results across different angular velocities or using a speed not relevant to the sport may reduce validity or relevance of findings.

Question 23

Which IKD protocols are differences in angular velocities most likely to affect? Why?

Answer 23

Strength, power and RFD
Torque and power outputs vary with speed, strength is higher at slower velocities, and power and RFD require testing at faster speeds for functional relevance.

Question 24

What is the solution to minimise angular velocity differences?

Answer 24

Test at multiple angular velocities, to better reflect real-world demands.
Choose a sport-specific speed to match the functional movement speed of the sport.
Use speed comparison diagnostically - observe how strength changes across velocities to detect performance deficits.

Question 25

What are the issues with using IKD as a measure of rehabilitation? What are the solutions?

Answer 25

1. Tests isolated strength not overall function and doesn't reflect real-life sport specific movements. Solution - combine with functional tests and dynamic task-specific assessments e.g. agility drills and change of direction tasks. Captures multi-joint, coordinated movements, ensure strength translates to performance demands. 2. The IKD may miss functional deficits e.g. coordination, control or timing deficits. Solution - use motion analysis or EMG alongside IKD. Reveals deficits in stability or control, supporting return-to-play decisions. EMG looks at timing of activation, balance between agonists/antagonists e.g. can detect delayed hamstring activation (risk factor for re-injury), quad dominance. More useful information. 3. Motivation and effort. Pain, fear of re-injury or low motivation may limit effort, reducing output accuracy and comparison to other results. Solution - use verbal encouragement, familiarisation trials and visual feedback. This increases confidence and motivation during testing. 4. Comparative validity - limb symmetry index issues. The 'uninvolved' limb may also be weak. Solution - use pre-injury baselines if available, or population norms, and assess both limbs regularly. Helps identify is both limbs have declined or recovered.

Question 26

What are the traditional metrics for IKD?

Answer 26

Peak torque and angle at peak torque

Question 27

What are the advantages of only using peak torque and angle at peak torque?

Answer 27

Quick analysis, easy to interpret, identify and record. Focus on maximal performance, usually main focus of training or rehabilitation. Angle at peak torque identifies optimal joint position for strength, useful in biomechanical analysis and exercise prescription. Lots of normative data to compare to. Can quickly identify asymmetries in strength between limbs, simple progress measure.

Question 28

What are the disadvantages to using only peak torque and angle at peak torque in IKD testing?

Answer 28

Ignores full performance profile - misses full range of motion, which would identify strength deficits at specific joint angles. Limited functional insight - real-life movement requires force production across multiple angles. Important rehabilitation parameters like torque at end range are not considered. Angle specificity can be misleading as influenced by joint speed, limb mechanics, testing conditions - comparisons are not reliable. Insensitive to muscle imbalances when not testing the full curve - legs may be imbalances but only at certain angles.

Question 29

Give some alternative IKD measures

Answer 29

Fatigue Index Average Torque Rate of torque development Agonist-Antagonist Ratios

Question 30

Average Torque Definition, advantage, description.

Answer 30

Mean torque throughout the range of motion. Gives a sense of consistent force production, not just the maximum effort. The ability to sustain force after generating it is very important for sports that require explosion and continued force production, or less explosive sports that require activity over a short period (Simpson et al., 2019). It is also important as a rehabilitation measure as athletes need strength throughout the movement pattern to stop re-injury. Important for non-athletes to complete daily living activities, and sustain strength throughout movements. May help identify an overall weakness rather than specific strength.

Question 31

Fatigue Index Definition, advantage and discussion

Answer 31

Percentage drop in torque over repeated contractions e.g. 15-30. Advantage: Measures muscle endurance and resistance to fatigue - applicable to lots of sports. It is a useful measure of the decline in performance over the course of the protocol. It can be used in rehabilitation programmes so patients are not required to immediately produce maximum force and can inform return to play decisions, as lots of sports require continuous activation which may put additional strain on a muscle/tendon/injury if not fully recovered. However, it is not necessarily the most reliable measure of fatigue as it only uses data from the first and last third of repetitions/single repetitions and so is not representative of the whole protocol (Evans et al., 2014). It can be influenced by outliers or pacing and tends to have lower test-retest reliability (Frykholm et al., 2018). Instead, producing a decay slope which measures the decline in torque across all repetitions or time points ins more reliable and better reflects the overall fatigue trend.

Question 32

Rate of Torque development Definition, Advantage and discussion

Answer 32

Speed at which force is generated (Torque/time). Indicates explosiveness and neuromuscular responsiveness. Used to measure performance in power sports that require explosive movements such as sprinting or powerlifting (Simpson et al,. 2019). It can also assess neuromuscular function post injury - rate of muscle fibre recruitment, activation etc.

Question 33

Agonist-Antagonist Ratios Definition, advantage and discussion

Answer 33

Ratio between opposing muscle groups Detects muscle imbalances within limbs. Can be used to compare to norms, as it is expressed as a ratio, you are not looking at the force output, but rather a comparison which makes it easier to compare to norms without considering differences in strength output. Injury risk benefits - monitoring and preventing. Monitoring post-injury and during rehabilitation can identify strength deficits and inform training practices. (Kellis et al., 2022). However, it should be used in conjunction with other measures such as bilateral differences in limb strength because although a risk factor for injury it does not fully predict injury risk. Bilateral differences > 15% have been shown to be a considerable risk factor for injury (Parkinson et al., 2021). Discuss additional issues with bilateral comparison - pre-injury strength etc.

Question 34

What are the advantages and disadvantages of velocity-based testing e.g. GymAware?

Answer 34

Mann, Ivey and Sayers 2015. Easily adapted to day-day fluctuations in performance, influenced by fatigue, nutrition and recovery. Maintains training at required velocity for sport-specific function. Maximises training without compromising velocity. Rather than focusing on 1RM based training protocols which may not successfully target the desired training focus. Reduces injury risk by avoiding excessive strain when power is the focus of training but load doesn’t match daily requirement. Do not need to wait weeks to retest 1RM, can see improvements in velocity at given loads without needing to conduct a max test. Provides immediate feedback to players which improves motivation. However, the constant adjustment of loads requires trust between coach and athlete to do it themselves, or greater level of input from the coach, in professional settings. Harder for recreational athletes to manage their own training, as unlikely to have access to the kit, 1RM testing is more accessible.

Question 35

What are three validity issues relating to velocity-based training

Answer 35

Bar path and exercise complexity Movement intent vs actual output Require a pause/isometric phase

Question 36

Why is bar path and exercise complexity a validity issue? What are the solutions?

Answer 36

VBT is most accurate in exercises with a straight vertical bar path e.g. deadlift, bench press. In lifts with multi-directional or ballistic movements e.g. Olympic lifts, kettlebell swings , speed is harder to capture accurately. Poor technique also skews velocity readings. Solutions. 1. Use the smith machine to maintain a straight bar path, not a functional movement in most cases whereas 1RM testing can be done with any exercise. 2. Include an isometric phase of the movement, as position of bar may change between reps influencing results. Can be restrictive, not functional and may affect fatigue.

Question 37

What is the issue with intent vs actual output? Solutions?

Answer 37

VBT assumes maximum intent during each rep — if an athlete isn’t pushing maximally, the velocity won’t reflect true performance. Inconsistent effort leads to unreliable or misleading results, even if the device is accurate. Solution 1. Ensure maximum performance using verbal encouragement. 2. If testing, use a familiarisation phase to ensure safety and maximum intent on measured repetition.

Question 38

What are the reliability issues?

Answer 38

Variation between sets/reps in form will affect velocity. Need to be used for every rep to ensure maximum training benefit, not just as a measure to adapt the weight relative to. Peak velocity is more reliable than mean velocity due to issues detecting start and end point. Limits comparison and functionality of the test.