SE102-4-SP Biomechanics Sport Assessment : Jump Technique Comparison Assignment: Squat vs Countermovement Analysis CWK Lab Report

Learning Outcomes of SE102-4-SP:

1. Give an account of underlying mechanical principles relevant to human movement.
2. Explain human movement in terms of anatomical and biomechanical principles.
3. Conduct a set of laboratory exercises relevant to the module, and write reports of these in appropriate scientific style.
4. Use theoretical principles to analyse and evaluate sporting technique in the context of injury prevention and performance enhancement.

SE102-4-SP Assessment Details:

A key sporting skill is the ability to produce maximal force to jump as high as possible. In this coursework, you will be analysing two different jump techniques (squat jump and countermovement jump) to determine which produces the greater height. This coursework is a comparison of the two techniques and will be written as a lab report. It must contain the following sections:

Title

Keep the title short and concise, no more than twelve words. The title should capture the aim of the practical.

Introduction (10%)

Give an introduction to key terms including an explanation as to why it is useful to be able to maximise jump height in sport. Give a background of the sport movement you are interested in and how this relates to the performance in your sport. Include aim/hypothesis of study (H0 and H1 format).

Method (10%) (Participants / Protocol / Calculations)

Your methodology is complete if someone else could repeat the experiment in the same way that you carried it out.

Results (20%)

Either as tabular or graphical format. Must include a short note of points of interest. Do give the means and standard deviation of data that are reported. Do not discuss the results in this section.

All of the data for this coursework have been stored in a class spreadsheet in eportobello. Your coursework must be written based on the data from the whole class.

Discussion (30%)

Explanation of results. Assume that the reader has knowledge of the area but is not an expert. The explanation should make reference to the information provided in the introduction, particularly the hypothesis. Any interpretation of the results should refer to the findings of previous investigations in the area. It is often necessary to include further references to support points that you are attempting to make.

As with the introduction your discussion should lead your reader through the discussion in a logical order. It may be helpful to start by discussing the participant group and how the group relates to the participants in previous studies.

Remember, the key focus of this study is to examine any effect SSC has on jump height when comparing a squat jump with a countermovement jump.

Conclusion (10%)

Summarise study, relating the main findings to the aims of the study and the hypothesis.

References (10%)

Full references must be given for any factual information, statements, quotes, diagrams or data that have been reported or reproduced, either partially or in full. Reference style to be used is Harvard format.

Writing Style / Structure (10%)

(See Marking Scheme for details)

SE102-4-SP Instructions To Students Including Submission Guidance:

The report should be 2000 +/-200 words in length. It is possible to roughly proportion the word count of each section according to the percentage of marks each attracts. The Introduction attracts 10% of the marks and should, therefore, consist of around 200 words. The discussion, however, is worth 30% of the marks and, accordingly, should consist of around 600 words.

The report should be written in the third person past tense. Example: “The cycle ergometer was set up to suit the subject.” – and not – “I set up the cycle ergometer to suit the subject.”

Notes:

• Please ensure the work is submitted with the following:
  • Page 1+2 = marking scheme – do NOT include student id or name
  • Page 3 = cover page which must include MODULE CODE, TITLE, WORD COUNT
  • Page 4 onwards – your report
  • Ensure you include headings for each section: “INTRODUCTION”, “METHOD”, “RESULTS”, “DISCUSSION”, “CONCLUSION”, “REFERENCES”

LAB GUIDE FOR SE102-4-SP – A COMPARISON OF JUMP TECHNIQUES

Assessment Details

A key sporting skill is the ability to produce maximal force to jump as high as possible. In this coursework, you will be analysing two different jump techniques (squat jump and countermovement jump) to determine which produces the greater height. This coursework is a comparison of the two techniques and will be written as a lab report. It must contain the following sections:

Introduction (Theoretical Background)

Human movement is rarely an isolated form of muscle contraction but rather a pairing of eccentric and concentric contractions (Komi, 2000). The stretch shortening cycle (SSC) occurs when a concentric contraction is immediately preceded by an eccentric contraction (Komi, 1984). The stretching of the active muscle allows for a more forceful concentric contraction. Examples of the SSC in everyday human movement are walking, running and jumping.

Efficient SSC produces higher forces at any given velocity (thus increasing jump height) (Flanagan and Commyns, 2008) and results in a reduced metabolic cost of movement, compared to an isolated concentric contraction (Cavagna et al., 1968). More force can be generated from the SSC mechanism the quicker the shortening occurs after the stretching of the muscle (Cavagna et al., 1968).

The release of stored potential elastic energy (EE) in the muscle complex (Cavagna et al., 1965), increased excitability of proprioceptors (Flanagan and Commyns, 2008), and the length of the muscle being closer to optimal (Turner and Jeffreys, 2010) are all proposed mechanisms of the performance enhancement involved with the SSC. The tendon is the primary site for EE storage and how much it stores is proportional to its deformation (which is a function of tendon stiffness) and the force applied. Higher levels of muscle stiffness increases the amount of stored and reused EE (Turner and Jeffreys, 2010). Muscle spindle excitability may increase recruitment of motor units and/or increased rate of firing of preciously recruited units during the eccentric contraction leading to force potentiation of the concentric contraction. Increased SSC efficiency leads to the possible reduction of the inhibitory effects of the golgi-tendon organ (GTO) that inhibits the pre-concentric contraction (Turner and Jeffreys, 2010).

The aim of this lab is to measure jump height and further metrics of both the CMJ and SJ. A comparison of key metrics will provide further insight into both jump methods to better inform athlete training in the future.

Step By Step Guide For Lab

1. Turn on forcedecks, open forcedecks app on laptop or phone app and connect to forcedcks via Bluetooth. The username for the app is brian.spring@portobelloinstitute.com and the password is Portobello23!
2. Create profile
3. Select profile
4. Zero the platform
5. Weigh subject on platform
6. Gather other subject information that may be useful for writing up lab report i.e. sport.
7. Complete familirisation jumps (2 CMJ and SJ)
8. Complete jumps for at least 3 subjects but more if time permits (ideally at least one male and one female).
   ForceDecks Dual Force Plate System – YouTube
   Force Decks Demo – YouTube
   CMJ protocol: Feet placed shoulder width apart, hands on the hips when jumping and participants are instructed that their body had to be kept straight in the air (i.e. no knee bend). The CMJ was performed by flexing at the knees and hips to a comfortable position and then immediately vertically jumping to their own maximum height. Performed 3 times with a 2-3 minute recover in-between each jump.
   SJ Protocol: Feet placed shoulder width apart, hands, on the hips when jumping and participants are instructed that their body had to be kept straight in the air (i.e. no knee bend). The SJ was performed by flexing at the knees and hips to a comfortable position and holding that position for 3 seconds before vertically jumping to their own maximum height. Performed 3 times with a 2-3mintue recover in-between each jump
9. Transfer raw data for all jumps into excel file (export as CSV)
10. Graph force data (example in results)
11. Calculate flight time, jump height, and max force production for all jumps.

Methods

Subjects were given coaching cues for each of the two jumps and two familiarisation trials on each jump prior to recording of data. The equipment used was a Vald performance force plate (ForceDecks | Dual Force Plate System | VALD Performance). Two subjects were tested at a time with one performing a jump and another undertaking the minimum rest time between jumps, of sixty seconds. The two participants undergoing testing were warmed up immediately prior, with a standardised warm-up consisting of 10 lunges (5 on each leg), calf stretching (alternating legs), 5 bodyweight squats and 5 jump squats. Subjects were given correct coaching cues and two familiarisation trials for each of the three jumps, immediately before testing. Subjects then performed each trial jump at maximum effort and with their hands on their hips. The force-time data from the force plate was transferred to a computer and the subsequent graphs were analysed to find body weight (BW), max ground reaction force (GRF), rate of force development (ROFD), time to reach max GRF, flight time, jump height, slow SSC performance and fast SSC performance and contact time for the drop jumps. From this we were able to analysis and compare the SSC function of the 6 subjects.

Results

Table 4: Counter-movement jump means

Write Up

Title

Keep the title short and concise, no more than twelve words. The title should capture the aim of the practical.

Introduction (10%)

Give an introduction to key terms including an explanation as to why it is useful to be able to maximise jump height in sport. Give a background of the sport movement you are interested in and how this relates to the performance in your sport. Include aim/hypothesis of study (H0 and H1 format).

Method (10%) (Participants / Protocol / Calculations)

Your methodology is complete if someone else could repeat the experiment in the same way that you carried it out.

• Do not copy the step by step guide (do not need to be as specific).

Results (20%)

Either as tabular or graphical format. Must include a short note of points of interest. Do give the means and standard deviation of data that are reported (this can be done through excel functions). Do not discuss the results in this section.

• All of the data for this coursework have been stored in a class spreadsheet in eportobello.
• Figures of comparison between key metrics in SJ and CMJ
• Table with all results of peak force, and jump height for each jump.
• Bar chart for average jump height for each subject
• Don’t use screenshots here, need to create your own graphs in excel.

Discussion (30%)

Explanation of results. Assume that the reader has knowledge of the area but is not an expert. The explanation should make reference to the information provided in the introduction, particularly the hypothesis. Any interpretation of the results should refer to the findings of previous investigations in the area. It is often necessary to include further references to support points that you are attempting to make.

As with the introduction your discussion should lead your reader through the discussion in a logical order. It may be helpful to start by discussing the participant group and how the group relates to the participants in previous studies.

Remember, the key focus of this study is to examine any effect SSC has on jump height when comparing a squat jump with a countermovement jump.

• Stretch shortening cycle
• CMJ vs SJ
• Mechanisms of SSC improving performance
• Previous research findings
• Between groups differences
• Within group differences

Conclusion (10%)

Summarise study, relating the main findings to the aims of the study and the hypothesis.

References (10%)

Full references must be given for any factual information, statements, quotes, diagrams or data that have been reported or reproduced, either partially or in full. Reference style to be used is Harvard format.

Writing Style / Structure (10%)

(See Marking Scheme for details)

The report should be 2000 +/-200 words in length. It is possible to roughly proportion the word count of each section according to the percentage of marks each attracts. The Introduction attracts 10% of the marks and should, therefore, consist of around 200 words. The discussion, however, is worth 30% of the marks and, accordingly, should consist of around 600 words.

The report should be written in the third person past tense. Example: “The cycle ergometer was set up to suit the subject.” – and not – “I set up the cycle ergometer to suit the subject.”

Notes:

• Please ensure the work is submitted with the following:
  • Page 1+2 = marking scheme – do NOT include student id or name
  • Page 3 = cover page which must include MODULE CODE, TITLE, WORD COUNT
  • Page 4 onwards – your report
• Ensure you include headings for each section: “INTRODUCTION”, “METHOD”, “RESULTS”, “DISCUSSION”, “CONCLUSION”, “REFERENCES”

Resources

Countermovement Jump or Squat Jump? (hawkindynamics.com)
Readings on eportobello