Is Maximum Strength Related to Vertical Jump Performance?

A number of studies have investigated the relationship between vertical jump performance (VJ), both in the squat jump (SJ) and countermovement jump (CMJ) to strength and power in single-joint isometric tests (Baker et al., 1994), multi-joint isometric tests (Haff et al., 1997; Haff et al., 2005; Kawamori et al., 2006), and multi-joint dynamic tests (Wisloff et al., 1998; Young et al., 1999).

Strength is  often associated with superior performance in sport (Stone et al., 2003). Several of the characteristics associated with strength (e.g., peak force, RFD, velocity, and power-generating capacity) have been identified as underlying mechanisms related to sports performance, particularly in the VJ (Stone et al., 2003; Peterson et al., 2006). According to several authors, success in sport depends upon the development of strength as well as power, both of which contribute to VJ performance (Baker et al., 1994; Stone et al., 2003; McGuigan and Winchester, 2008). Furthermore, training-induced increases in measures of maximum strength have been shown to result in VJ height increases (Stone et al., 1979; Stone et al., 2003).

BMS Example

Explosiveness is an important aspect of physical performance, and may be defined as requiring one to produce as much force as possible within a limited time window (usually < 200 ms). It could be hypothesized that if you are more explosive, one should jump higher, sprint faster, change direction quicker, for example. Vertical jumping ability has been shown to have a strong correlation with many other fundamental explosive movements including sprint performance (Peterson et al., 2006), ability to change direction (Brughelli et al., 2008), baseball bat velocity (Szymanski et al., 2010), weightlifting performance (Carlock et al., 2004), and sprint cycling (Stone et al., 2004).

Here is a table detailing studies looking at the relationship between maximal strength and VJ performance.

Squat Jump

Although a correlation does not determine a cause-and-effect relationship, a few factors can in part explain the reported relationships.

To optimize VJ performance, produced force should be directed as vertically to the ground as possible. If produced force is not directed vertically, the resulting jump will contain horizontal displacement proportional to the magnitude of force (Hall, 2007). However, in other horizontal movements, vertical force has still been reported to be a key factor in performance. Weyand et al., (2000) reported that vertical force production is as important, if not more, as horizontal force for achieving greater running speeds in sprinting. Previous data has also suggested that stronger athletes (back squat ≥ 2 kg/kg) may have advantages in exhibiting a potentiation effect in a horizontal plyometric activity after performing an ascending back squat protocol (Ruben et al., 2010).

Neuromuscular activation patterns in dynamic explosive movements (performed with maximum effort to accelerate) have been shown to be different from non-explosive movements (non-ballistic movements without maximum effort to accelerate) (Cormie et al., 2011b; Cormie et al., 2011a). In particular, firing frequency and synchronization of motor units have been reported to be greater in explosive movements (Komi, 1992). In addition, if effective, many training modalities have shown to improve VJ height; including conventional resistance training, ballistic and semi-ballistic resistance training, and plyometric training.

Stronger athletes manage the eccentric load during SSC movements more efficiently as they are able to increase concentric force as a result, which should result in higher jump heights. The ability to increase force at a given eccentric velocity & increase velocity of the descent, allows the use of the eccentric phase in SSC movements more efficiently to generate an increase in power during sporting movements. Stronger athletes are able to increase unloading, and by tolerating high stretch loads they generate during quick eccentric actions, they use this to translate momentum into force, resulting in an increased stiffness, eccentric force, rate of force development, and power during explosive movements.

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Periodization: Theory and Methodology of Training 2

This post will carry on from the post last week detailing the remainder of Periodization: Training Theory and Methodology.

Chapter 7 – Peaking for Competition

A taper can be defined as a decrease in workload prior to competition to optimize performance at a specific time. This can be affected by volume (sets/reps), frequency (density), or load (absolute or %1RM). The goal is to dissipate fatigue while maintaining fitness gains, thus increasing preparedness.

Taper 1

Several studies have looked at the manipulation of the above variables when tapering/peaking for competition. A maintenance or increase in intensity while decreasing volume and frequency has shown to maintain training induced adaptations. Volume can be decreased through less time of sessions, or less no. of sessions across the microcycle, or both. It is probably more effective to decrease the duration of sessions rather than the no. of sessions, that way they will still be exposed to frequent stimuli in a wave like cycle as opposed to constant, moderate stress. A 50-70% drop in volume is recommended, with ‘optimal’ found between 41-60%. If training load is very heavy then a drop in training load between 60-90% may be warranted. Performance only seems to increase with a reduction in volume through duration, while maintaining frequency of training at 80% or more of pre-taper values.

The duration of the taper depends on the pre-taper load, although it is highly individualized, around 8-14 days is recommended.

Tapers can be defined as progressive or non-progressive.

Taper 2

Progressive

Linear taper – involves a linear decrease in training load.

Slow exponential taper – slower decrease in training load, so still end up working at higher training loads

Fast exponential taper – appears to have increased results than linear and slow exponential

Non-progressive

Step taper – involves a standardized decrease in raining load (sudden drop in training load)

If properly implemented, approximately a 3% elevation in performance can occur. The type of taper used will depend on major competitions, competition schedules, and competition frequency.

Chapter 8 – Training Cycles

The microcycle is a 3-7 day programme (usually 7 days) consisting of structured technical, tactical, speed, agility, power, strength and special endurance. It should be developed to meet the objectives of the training phase influenced by the athletes development, training capacity, and no. of sessions available/required.

Possibly at least 22 microcycle structures are available, therefore to avoid over-complicating things use the most common and adapt it to the individual training needs.

A development microcycle can be useful during the preparatory phase to increase adaptation, increase skills through flat/step loading. Shock loading suddenly increases training demands through planned overreaching/concentrated loading. Recovery microcycles will fluctuate between regeneration days, peaking, and unloading before competition. The sequencing (2 days loading/1 day unload for example) depends on the competition schedule.

Several authors suggest alternating heavy and light days, through manipulation of volume load, %1RM, or rate of perceived exertion (RPE).

The macrocycle usually lasts 2-7 weeks based on the training objectives, phase of training, and competition schedule. Preparatory phase is suited to development and shock microcycles where the volume will be higher to acquire adaption and skills. The competitive phase should include steady loading patterns through varying the intensity to plan around competition and peak for certain times (4:1, 3:1, 2:1, 1:1, 2:2 paradigms).

Chapter 9 – Workout Planning

Planning gives structure and effectively guides the training process. Developing long term plans guides the development of the athlete if there is continuity between microcycles and macrocycles – however there must be flexibility.

Testing and monitoring should be integrated and contain tests that target development. Daily monitoring is vitally important to gain a feel for the tolerance of training load. Testing and monitoring should examine results, determine weak areas and then target those weaknesses in the new training plan.

For the session design refer to a previous blog post.

The duration on each component of the session changes with time available, focus of the session, and fatigue (peripheral and central).

Chapter 10 – Strength and Power Development

Strength is related to sprint, NFL, soccer, volleyball, ice hockey, rugby league, and aerobic endurance performance. Force = Mass. Acceleration and the whole force-velocity curve must be targeted in order to improve sports performance.

Strength Classification

Factors Affecting Strength

Motor unit recruitment – large motor units are activated in response to high external loads

Motor unit rate coding – motor unit firing frequency is dependent upon the speed of voluntary contraction. An increase in firing rate will increase the rate of force developed

Motor unit synchronization – simultaneous activation of numerous motor units plays an important role in force development during rapid contractions.

Neuromuscular Inhibition – the golgi tendon organ (GTO) prevents generation of harmful muscular forces during maximal efforts. If excessive tension is perceived by the neural system, an inhibitory signal is sent by the GTO to reduce neural input and moderate force output.

Muscle fibre type – Strength and power training targets Type II fibres, which is advantageous in most sports

Muscle hypertrophy – increases in cross sectional area result in an increase no. of contractile units, increasing force generating capacity.

Strength Loads

For a detailed analysis on repetition/set schemes for strength see the following articles
APPLICATIONS OF THE DOSE-RESPONSE FOR MUSCULAR STRENGTH DEVELOPMENT
MAXIMIZING STRENGTH DEVELOPMENT IN ATHLETES A META-ANALYSIS TO DETERMINE THE DOSE-RESPONSE RELATIONSHIP.

I have decided not to discuss speed, agility and endurance as they were briefly described in the first post.

Is Maximum Strength Related to Sprint Performance?

A number of studies have investigated the relationship between strength and sprint performance, demonstrating that, in general, stronger athletes perform better during sprint performances (Baker and Nance, 1999; Hori et al., 2008; Comfort et al., 2012). This may be explained by the fact that peak ground reaction forces and impulse are strong determinants of sprint performance (Weyand et al., 2000).

Studies have used various methods to assess strength; including isokinetics (Blazevich and Jenkins, 1998), machine squats (Harris et al., 2008) and free weight squats (McBride et al., 2009; Comfort et al., 2012a), when investigating the relationship between strength and sprint performance.

F = ma

The table below summarizes a few recent studies either investigating the relationship between maximal strength and sprint performance, or the effect of a strength training intervention on sprint performance.

Strength Sprint

Yes there are limitations to each of the below studies, but there is a common trend – stronger athletes are faster. This doesn’t mean that if you’re back squat improves you will automatically be faster (you probably will though, depending on ability), but maximal strength plays an important part of the transfer to athletic performance as means to an end. Technique factors such as stride length and stride rate should be based on anthropometric and force capabilities. F = m.a – so the force applied will determine the acceleration rate but also how effectively force is applied is sometimes more important than the total magnitude of the force.