An Evaluation of the Validity of Dyno Test in Climbers

Sources: Submitted by author
Author: Paul Martin (peue01@hotmail.co.uk)
Institution: University of Wales Bangor

ABSTRACT:
Bouldering is low level technical rock climbing without ropes that aims to ascend short difficult sections of rock that may have limited holds or require special techniques for a successful ascent. In bouldering, a "dyno" (dynamic movement technique) uses thrust initiated primarily in the legs, to propel the body to the next available hold If that hold is out of normal reaching distance (Goddard & Newman, 1993). The skills or attributes that unite to give an efficient and strong dyno performance are not yet known. This may be due to a lack of research in this area resulting from the absence of a valid measurement of dyno performance. This study aims to validate the measurement of a dyno. It also aims to identify the major attributes that may be required for a climber to perform an efficient dyno. 20 male subjects aged between 19 and 26 years old with varied experience of rock climbing volunteered to participate in this study. The volunteers were assigned to an elite group or a novice group determined by a maximum possible grade cut-off criterion. Participants were then subjected to a selection of validated measures including standing jump, grip strength, and anthropometrical measurements of arm and leg lengths, arm span, and APE index (arm span divided by height). Dyno performance was tested using a custom built dyno specific climbing wall on which participants were asked to perform three maximum effort dyno's.

There was a significant difference between novice and elite climbers on measures of grip strength (Elite = 55.8 ± 6.3, Novice = 38.9 ± 8.7, P = <0.01), dyno performance (Elite = 2.3 ± 0.8, Novice = 0.8 ± 0.8, P = <0.01) and jump height (Elite = 41.6 ± 5.4, Novice = 32.4 ± 7.5, P= <0.01). There was no significant difference in reach between the two groups (Elite = 238.1 ± 12.1, Novice = 235.8 ± 12.4, P = 0.82). No significant differences were seen between anthropometrical measures of average leg length (Elite = 111 ± 7.5, Novice = 112.4 ± 7.8, P= 0.57), average arm lengths (Elite = 71.1 ± 4.6, Novice = 73.8 ± 4.8, P= 0.18), APE index (Elite = 1 ± 0.0, Novice = 1 ± 0.0, P= 0.31), Height (Elite = 176 ± 7.2, Novice = 174.9 ± 9.0, P= 0.14), or arm span (Elite = 181.4 ± 9.2, Novice = 182.3 ± 11.8, P= 0.74). There was a Significant correlation between grip strength and dyno performance (r =.768, P = <0.01), but no significant correlation was seen between jump height and dyno performance (R = 0.432, P = 0.57). Additionally, significant correlations to dyno performance were seen between anthropometric measures of arm span (R = .449, P = 0.047), height (R = .609, P = .004), average leg length (R = .597, P = .005) and reach (R = .527, P = .017). No significant correlations to dyno performance were seen in measures of ape index (R = .000, P = 1.0) or average arm length (R = .315, P = .177). Although significant differences were seen between novice and elite climbers on measures of grip strength, dyno performance and jump height, a significant correlation of jump height to dyno performance was not seen. However there was a trend towards significance and it may be possible that this study was limited by sample size and a study with greater power may boost these results to a level that reaches statistical significance. The data suggests that measures of grip strength, standing jump and dyno performance discriminate between novice and elite climbers demonstrating discriminate validity.

DISCUSSION:
As hypothesised, the significant difference between novice and elite climbers on the measure of dyno performance demonstrates discriminate validity. However, no significant differences were seen between novice and elite climbers on anthropometrical measures suggesting that these do not influence dyno performance.

This is consistent with the findings of Mermier (2000) who concluded that anthropometric characteristics of climbers such as arm length, leg length, arm span, and the so called APE index (arm span/height) do not appear to be vastly different from non-climber control values. It was also stated that trainable variables such as strength and power accounted for the greatest percent of variance in climbing ability. Mermier (2000) continued to point out that only percent body fat and grip strength to body mass ratio were considered to be significant predictors of climbing ability and that climbers do not necessarily need to possess specific anthropometric characteristics to be successful in sport rock climbing. In this past research, grip strength has been shown to significantly predict climbing performance. The findings of this study confirm the results of Mermier (2000). For example, height, although significantly correlated to dyno performance, does not significantly differentiate novice and elite climbers. This may be explained by the significant difference between novice and elite climbers grip strength and the significant correlation of grip strength to dyno performance that was observed inferring that although a climber may be taller and able to reach higher holds during a dyno, there may be insufficient grip strength to successfully latch onto the hold when it is reached, backing the theory that anthropometric characteristics may not be as important as strength characteristics when predicting dyno performance. Watts et al, (1993) characterised elite climbers as being small in stature, with a high grip strength to body mass ratio, and this was reinforced by Grant, (1996) who found that hand grip strength and finger strength appear to be higher in elite climbers than in recreational or non-climbers. This study has supported these previous findings and grip strength may therefore, be considered a major trainable variable that determines success in dyno's. However, in order to confirm this assumption, intervention studies that aim to increase grip strength to determine the cause and effect of this relationship are recommended.

Conversely, no significant correlation was seen between jump height and dyno performance despite the ability of this variable to significantly discriminate between elite and novice climbers. The fact that the correlation was not significant should not rule out the possibility of this variable being an important determinant of dyno performance. There was a clear trend towards a significant positive correlation observed and it is possible that a study with a larger sample size would increase the power of this trend to a level that reaches statistical significance. On average, elite climbers jumped 13.5% higher than novice climbers, demonstrating the likely importance of this variable as a determinant of dyno performance and supporting the inference that elite climbers are capable of producing longer dyno's while also being more capable of grasping the finishing holds. As with grip strength, further intervention studies that implement plyometric training to improve dyno performance by improving jumping ability would confirm that jumping ability is a significant variable that determines dyno performance.

In support of the previous literature, no significant correlations to dyno performance were seen in anthropometrical measures of ape index or average arm length. However significant correlations to dyno performance were seen between anthropometric measures of arm span, height, leg length and reach suggesting that overall, dyno performance may be aided by some aspects of an individual's stature, but the "ideal stature" may not be unique to either novice or elite climbers.

Dynamic movement is a major component of a modern day sport climbers overall ability (Goddard & Newman, 1993). Therefore research into the determinants of dyno performance has the potential to improve our understanding of overall climbing ability and potentially influence training methods of the future. The findings of this study reinforce and potentially re-emphasise the importance of advancing modern training advice for climbers that so far recommends dynamic forms of training such as one arm traverses (that isolate many of the principles of dynamic movement), or exaggeration of dynamic techniques on easy ground, to help familiarise the climber with dynamic movement (Goddard & Newman, 1993). The results of this study have suggested that improvement of grip strength, identified as being one of the most significant and trainable determinants of climbing ability, may improve dyno ability and overall climbing performance as a result. Mermier et al (2000) upholds a common belief when he states that climbers of all abilities who are interested in improving, would benefit from research into determinants of climbing performance. This study has successfully confirmed the findings of previous research and potentially furthered our understanding of the determinants of good climbing performance, while opening the gate way to an abundance of potentially very beneficial further research questions despite being hindered by some limitations.
A small sample size resulted in potentially weak statistical power as demonstrated by the inability of the analysis to show a statistically significant correlation of jump height to dyno performance. Additionally, the participants were drawn from a combination of third year sport science students and college age students that volunteered on the spot while the researcher was based in the climbing wall. Therefore this study may not be generalisable to a wider climbing population which may have a greater diversity of age or to other climbing styles such as traditional or aid climbing that rarely if at all use dyno's.

One possible limitation or at least an area that may be improved in future was the design of the dyno specific climbing wall and its fixed starting position. This was unchanged regardless of the leg length or height of the individual. Taller subjects complained of difficultly getting into the squatted starting position while smaller individuals complained of not enough leverage for pushing off into the dyno. Any researchers who wished to replicate this study may benefit from using an adjustable set of starting foot holds or a selection of starting footholds to provide the subjects with a choice of optimum starting positions. However, it is possible that this may provide an unfair advantage in some cases and it may be more appropriate to devise a method of re-setting the starting footholds for each individual, based on a certain percentage of a subject's height for example.
Distance between, or the number of available finishing holds may be improved in future studies. When an individual performed a dyno it was common place for the hand to fall half way between two finishing holds. No grasp would be made and the score would be recorded as zero for novice or elite climbers alike. To increase the sensitivity of this measure, a more efficient wall may use more frequent finishing holds with smaller distances between them to reduce the number of zero scores and allow performance to be judged more accurately.

Researchers may wish to further investigate the possibility of motor control issues that may influence the ability of a climber to successfully dyno such as accuracy and the ability to correctly time the sequence of movements involved in a dyno. Possible future research may investigate over or under shooting of target holds in elite and novice climbers.

Watts et al, (1993) in his study into the anthropometric profiles of elite male and female competitive climbers, categorised absolute grip strength in elite climbers as being only "moderate" and suggested that high grip strength to body mass ratios were more likely due to the effect of low body mass. Body mass was not measured in this study so to further strengthen the results or to increase understanding in this area, measures of body mass, percent body fat, and the grip strength to body weight ratio may be beneficial to include. It may be hypothesised that grip strength to body weight ratio and percent body fat may be significantly correlated to dyno performance.
Researchers may wish to investigate the possibility of contact strength being a significant determinant of dyno ability and further more the possibility of contact strength being directly affected by grip strength to body mass ratio. Contact strength is described as a climber's ability to summon strength quickly or the ability to quickly stick (draw in) a handhold at the end of a lunge. For example, a climber who has less absolute strength but more power can summon strength more quickly (greater contact strength) and will be more successful at performing dyno's and quickly latching onto holds (Horst 2003). Contact strength may be a determinant of dyno ability and it may be reasonable to assume that novice climbers would have less contact strength than elite climbers, therefore having a direct affect on overall climbing performance. However it is unclear if there has been successful measurement of contact strength and as yet there appears to be no evidence of its use or measurement in the literature. Further research may investigate the possibility of validating a measure of contact strength. This may be achieved through the use of a grip strength dynamometer and a measure of rate of force development in the forearm. A measure of contact strength may potentially then be correlated to dyno ability.

It has been stated that much of the past research that has sought to measure anthropometric variables and correlate them with indices of climbing performance has been largely descriptive - that is, no climbing specific training interventions or comparison with non-climbing control groups - with relatively small sample sizes (Sheel, 2004). In conclusion, this study has indeed suffered with the limitations of previous research but has successfully reinforced their findings. Additionally this study has validated dyno measurement and determined that grip strength plays a major role in a climber's dyno ability. However, as suggested by Sheel (2004), further studies that implement training interventions on the variables of grip strength and jump ability are required to further this research and determine cause and effect between these variables and dyno performance.
It has been suggested that success in climbing is related to the interaction of multiple variables (Mermier et al. 2000) and this study has demonstrated that jumping ability is likely to be significantly correlated to dyno performance in a study with greater statistical power. While height and some aspects of an individual's stature may combine to some small extent to produce a definitive dyno performance, this study suggests that future intervention studies will show that in terms of performance measures, it will be grip strength that ultimately determines successful dyno completion. The possibility of dyno measurement as a predictor of overall climbing performance should also be investigated.