Lock-off Strength Training (I). Does Static (lock-offs) Training have any Effect over Dynamic (pull-ups) Performance?

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In the previous entry, we tried to answer the first part of Randy's question. No we'll tackle the second:
...It seems I've heard of so many climbers see positive benefits from lock-offs in improving pulling strength.

Undoubtedly, if we train lock-offs we will be better at locking off, but there's a catch:
We will only improve the angle we are training with. Also, to this date there is no reason to believe that a given point of an exercise's range of motion is representative of the whole motion in well-trained people (Wilson and Murphy, 1996).

Percentage gain in isometric strength of elbow flexors due to isometric training at different elbow angles. Data from C. Thèpaut-Mathieu et al, 1968. Source: Fleck and Kraemer (2004)

However, these training effects can be different in non-trained people. For example, Folland et al (2005) did a study with 33 recreationally active males (healthy nonathletes or individuals physically active without an appropriate definition of performance level) and compared the strength gains produced by isometric training at four joint angles with conventional dynamic training. The increase in isokinetic strength was similar in both legs, but we have to keep in mind that this effect happened for non-trained people.

A different issue, but crucial to our purposes, is to consider whether it is worth to specifically work this skill, and the best way to do it. At this point, as often happens, more questions arise. I'll try to arrange this and the following entries so that they address the following:
The impact of static (lock-offs) training over dynamic (pull-ups) performance; what aspects of this discussion can help us being more aware when building a firm base for our training; and, what all of the above has to do with real climbing and actual performance.

Patxi Usobiaga. Photo: Rainer Eder

1- Will we improve our pulling strength, a dynamic concept by definition, by doing lock-offs?
2- Conversely, will we improve our locking strength by doing pull-ups?
3- What about mixing dynamic contractions with lock-offs in the same exercise, like functional isometric or Cometti's static-dynamic pull-ups?
4- What is the weight of our lock-off ability in our global performance?, Is it so important to train it?
5- What kind of climber or climbing style could get the greatest benefit from lock-offs, and what would be the most effective and safe method?

J.M. Archer Thompson ( (1863-1913), a pioneer climbing with an appreciation of bouldering...Source: wwww.johngill.net

1- Will we improve our pulling strength, a dynamic concept by definition, by doing lock-offs?
Does isometric training transfer to dynamic performance? We can guess that, given that the muscular contraction mechanism is the same for dynamic and static activations, we could answer yes to the above questions. But, as usual, things are not so straightforward.

The literature suggests that the increase in strength is closely related to the way it is achieved. The gains obtained using a certain joint angle, speed, position, or activation (static or dynamic), have little transfer to performance under different ones (González-Badillo and Izquierdo, M., 2008).

Ramón Julián

The overall effectiveness of isometric training on dynamic explosive force production is relatively minor, particularly among well-trained strength-power athletes (Hakkinen, 1994).

2- Conversely, will we improve our locking strength by doing pull-ups?
It's been shown that a MIF (maximum isometric force) test is a good predictor of maximum dynamic force (1RM or 1 repetition maximum) (McGuigan and Winchester, 1998; Juneja et al, 2010).

However, according several studies, like the ones reviewed by Baker et al. (1994), after training with a dynamic exercise, the gains measured in the dynamic test did not correlate with the gains in the isometric test. And this fact was even more evident the higher was the athlete's sport level.
All of the above mean that, for example, the individuals with the biggest gains doing pull-ups with added weight did not experience the same improvement when it came to bearing weight while locking-off with a 90º elbow angle.

Source:  Historical Performances in chin-ups, pull-ups, levers, and crosses

Conclusions
Duchautau and Hainaud (1984) suggest that human muscle adapts differently to isometric or to dynamic training programs. According to Baker et al (1994), the mechanisms that contribute to enhanced dynamic strength appeared unrelated to the mechanisms that contribute to enhanced isometric strength.  The results of their studies demonstrated that a generality of muscle function did not exist and that modality specific results were observed.

In practice, according to the consulted scientific literature, we could suggest that even if there is some relation between pull-up maximum strength and locking-off strength at the optimal angle (Murphy et al. (1995) suggested that the best angle to use for comparison with performance scores is the one which produces peak force, 90º in our case), training lock-offs would improve our performance at the training angle, but it would not mean proportional gains in pull-ups, and vice versa.

We will try to provide further information through the following entries:
3- What about mixing dynamic contractions with lock-offs in the same exercise, like functional isometric or Cometti's static-dynamic pull-ups?
4- What is the weight of our ability to lock-off in our global performance?, Is it so important to train it?
5- What kind of climber or climbing style could get the greatest benefit from lock-offs, and what would be the most effective and safe method?

REFERENCES

• Baker, D.; Wilson, G. and Carlyon, B. (1994): Generality versus specificity: a comparison of dynamic and isometric measures of strength and speed-strength. European Journal of Applied Physiology and occupational Physiolog. Volume 68, Number 4, 350-355
• Duchateau, J. and Hainaud, K.(1984): Isometric or dynamic training: differential effects on mechanical properties of a human muscle. Journal of Applied Physiology February 1, vol. 56 no. 2 296-301McGuigan, M.R. and Winchester, J.B. (2008): The relationship between isometric and dynamic strength in college football players. Journal of Sports Science and Medicine 7, 101-105
• Folland, J.P.;  Hawker, K.; Leach, B.; Little, T.; Jones D. (2005):  Strength training: isometric training at a range of joint angles versus dynamic training. Journal of Sports Sciences; 23(8):817-24
• Fleck, S.J, and Kraemer, W.J. (2004): Designing Resistance Training Programs. Human Kinetics.
• González-Badillo, JJ, and Izquierdo, M. (2008): Evaluación de la fuerza en el control del entrenamiento y el rendimiento deportivo. En Izquierdo, M. (editor); Biomecánica y Bases Neuromusculares de la Actividad Física y el Deporte. Panamericana
• Guy, M., Piatt, C.; Himmelberg, L.; Ballmann, K. and Mayhew, J. L. (1996): Isometric strength measurements as predictors of physical performance in college men. IAHPERD Journal Vol 30, 1. 
• Hakkinen, K. 1994: Neuromuscular adaptation during strength training, aging, detraining and inmobilization. Critical Reviews in Physical and Rehabilitation Medicine 6:161-198 
• Juneja, H., Verma, S. K, Khanna,(2010): Isometric Strength and Its Relationship to Dynamic Performance: A Systematic Review. Journal of Exercise Science and Physiotherapy, Vol. 6, No. 2: 60-69.
• Murphy AJ, Wilson GJ, Pryor JF, Newton RJ (1995): Isometric assessment of muscular function: the effect of joint angle. J Appl Biomech 11: 205
• Viitasalo JT (1982): Anthropometric and physical performance characteristics of male volleyball players. Can J Appl Sport Sci. Sep;7(3):182-8.
• Wilson GJ, and Murphy AJ.  (1996): The use of isometric tests of muscular function in athletic assessment. Sports Med. Jul;22(1):19-37