Scientific abstracts are the hooks attempting to capture a discerning reader's attention, the shortcuts saving the busy reader some time and the keys unlocking scientific knowledge for those lacking a portfolio of academic journal subscriptions. But don't be dismayed if you're still confused after reading an abstract multiple times. When writing this leading, summarizing paragraph of a scientific manuscript, researchers often make mistakes. Some authors include too much information about the experimental methods while forgetting to announce what they actually discovered. Others forget to include any methodology at all. Sometimes the scientists fail to divulge why they even conducted the study in the first place, yet feel comfortable boldly speculating with a loose-fitting claim of general importance. Nevertheless, the abstract serves a critical importance and every science enthusiast needs to become comfortable with reading them.
A well-written abstract typically provides several basic types of information about a research project in concise arrangement, facilitating the reader's ability to quickly ascertain the context, questions asked or purpose, results & methodology, interpretation and conclusions of one particular line of experimentation. The presentation style can vary widely from publisher to publisher, but each important element can often be identified by language cues or even more simply, by the order of the sentences. The following abstract was published in the journal I work for, Nature, and contains most of the classic facets outlined above. Let's walk through it:
Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes.
-- The CONTEXT of the study. These 1-2 sentences provide background information required to understand the history of a field and establishes a framework to conceptualize the PURPOSE of a study. As it is here, this usually is presented first.
We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe.
-- The QUESTION or PURPOSE of the study is typically provided after the context. It can be in the form of a general query, an experimental goal and/or allude to a specific agenda. In this particular case, one has to read between the lines and perceive the authors interest in wondering why we even need modern running shoes if in fact humans have been running barefoot for millions of years.
Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe.
-- It's a stylistic call whether to provide the RESULTS or METHODOLOGY after stating the QUESTION. In this case, the authors next offer the single biggest result in the paper that will be the basis for all subsequent interpretation. The take-away message from these sentences is that barefoot runners strike the ground differently than those wearing modern running shoes.
Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers.
-- A brief reference to the METHODOLOGY, involving kinematic and kinetic analyses. Of course, the conciseness of an abstract led the authors to imply most of the methodology, namely that foot placement upon ground impact was compared between barefoot and shod runners. So, like in this example, it is often important to extract methods from the description of the RESULTS.
This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground.
-- Now the authors provide an INTERPRETATION of their data, providing an explanation as to why barefoot runners generate smaller collision forces upon ground impact than shod runners. Not all abstracts provide data interpretation, with some authors preferring to leave that to the full-length paper.
Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.
-- Abstracts usually end with some final CONCLUSIONS to speculate on the origin of the observations, what the field can learn from the results, or to suggest future directions in extending their own research. Here, the authors ponder the implications of their INTERPRETATION and speculate on a possible mechanism for common impact-related injuries seen today, thus indirectly proposing future lines of clinical research to test this proposal that strike gait leads to runner injury. It is critical to note that these authors have not confirmed any causation for runner injury. They have only suggested a possible source. It is also interesting to note that this possible connection to injury was not the motivation for the study (as revealed in the QUESTION above.) These concluding remarks could easily be misinterpreted and thus a careful reading of the abstract is required to recognize the difference between the RESULTS section of the abstract and the speculation that often comes afterwards.
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Now it's time to apply your training to another abstract, which also happens to demonstrate just how the slow and steady forward march of science occurs in response to publications. Another group conducted their own research comparing barefoot and shod runners, but using different methods, came to different conclusions regarding the promotion of barefoot running as the superior practice. See if you can identify each of the important abstract elements:
Based on mass alone, one might intuit that running barefoot would exact a lower metabolic cost than running in shoes. Numerous studies have shown that adding mass to shoes increases submaximal oxygen uptake (V˙2) by about 1% per 100 grams per shoe. However, only two of the seven studies on the topic have found a statistically significant difference in (V˙2) between barefoot and shod running. The lack of difference found in these studies suggests that factors other than shoe mass (e.g. barefoot running experience, foot-strike pattern, shoe construction) may play important roles in determining the metabolic cost of barefoot vs. shod running. Our goal was to quantify the metabolic effects of adding mass to the feet and compare oxygen uptake and metabolic power during barefoot vs. shod running while controlling for barefoot running experience, foot-strike pattern and footwear. 12 males with substantial barefoot running experience ran at 3.35 m/s with a mid-foot strike pattern on a motorized treadmill, both barefoot and in lightweight cushioned shoes (∼150 g/shoe). In additional trials, we attached small lead strips to each foot/shoe (∼150, ∼300, ∼450 g). For each condition, we measured subjects' rates of oxygen consumption and carbon dioxide production and calculated metabolic power. V˙2 increased by approximately 1% for each 100 g added per foot, whether barefoot or shod (p
[NO PEEKING AT THE ANSWERS TILL YOU'RE DONE.]
[OKAY PENCILS DOWN]
ANSWERS:
Based on mass alone, one might intuit that running barefoot would exact a lower metabolic cost than running in shoes. Numerous studies have shown that adding mass to shoes increases submaximal oxygen uptake (V˙2) by about 1% per 100 grams per shoe. However, only two of the seven studies on the topic have found a statistically significant difference in (V˙2) between barefoot and shod running. The lack of difference found in these studies suggests that factors other than shoe mass (e.g. barefoot running experience, foot-strike pattern, shoe construction) may play important roles in determining the metabolic cost of barefoot vs. shod running.
-- CONTEXT
Our goal was to quantify the metabolic effects of adding mass to the feet and compare oxygen uptake and metabolic power during barefoot vs. shod running while controlling for barefoot running experience, foot-strike pattern and footwear.
-- PURPOSE
12 males with substantial barefoot running experience ran at 3.35 m/s with a mid-foot strike pattern on a motorized treadmill, both barefoot and in lightweight cushioned shoes (∼150 g/shoe). In additional trials, we attached small lead strips to each foot/shoe (∼150, ∼300, ∼450 g). For each condition, we measured subjects' rates of oxygen consumption and carbon dioxide production and calculated metabolic power.
-- METHODOLOGY
V˙2 increased by approximately 1% for each 100 g added per foot, whether barefoot or shod (p
-- RESULTS
Running barefoot offers no metabolic advantage over running in lightweight, cushioned shoes.
-- INTERPRETATION and CONCLUSION
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When written up and published in manuscript format, scientific data and information have already passed through unavoidable filters represented by the authors and journal editors. However, with the ability to regularly recognize key scientific components from an abstract, the savvy reader will be in a position to better-police that other omnipresent science information filter, the one that sometimes operates with mixed efficiency: mainstream media.
References
1.Nature 463, 531-535 (28 January 2010)
2.Medicine & Science in Sports & Exercise, POST ACCEPTANCE, 2 March 2012
doi: 10.1249/MSS.0b013e3182514a88