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Physiological components of fitness as determinants of sprinting performance: muscular strength, anaerobic power, and aerobic capacity
Scott Lee
Writer's comment: While lectures and exams are essential components of my undergraduate education at UC Davis, I often feel confined to a passive role of accepting the information handed to me. Thus, I relish any opportunity to pursue my own academic interests. When Pamela Demory assigned a review article for her English 104E (Science Writing) class, I took full advantage of the academic freedom she granted me. I decided to combine my experiences as a sprinter on the UC Davis Track and Field team and an intern with the UC Davis Sports Medicine Group and investigate the physiological determinants of sprinting performance. My interest in the subject, along with expert editing by Professor Demory, made it much easier to synthesize the dense scientific information presented in the journal articles. The insight I gained into various testing protocols and training programs helped me understand the principles behind my own athletic training. I also hope that the article will help educate others about the growing field of applied biomedical research, the lack of research dedicated to sprint-based events, and the potential health and fitness benefits of additional research. Furthermore, my response to this assignment has helped develop advanced fitness testing on members of UC Davis athletic teams.
—Scott Lee
Instructor's comment: Scott wrote this fine article in response to a standard assignment in English 104E (Science Writing): the scientific review article. This challenging assignment requires students to find a cutting-edge area of research in their field, research that topic in the scientific literature, and then synthesize that material for an audience of interested professionals. Scott succeeds admirably on all counts. He found a topic that allowed him to combine his experience as a track and field athlete with his academic work as a pre-med student and researcher: current research on the physiological components of fitness—specifically as they relate to sprint performance. One of the most commendable aspects of this paper is its focus: Scott chose to research the literature on sprint performance only, explaining that research has traditionally focused on long-distance running, but then subdivides that small topic into the three inter-related factors of muscular strength, anaerobic power, and aerobic capacity. The result is a wonderfully in-depth analysis of recent research on the topic.
—Pamela Demory, University Writing Program
The relationship between the processing of music and language in the brain has long been a topic of scientific debate. Some claim that the two systems operate completely independently, with language exhibiting left hemisphere lateralization and music right lateralization. Others go so far as to say that music and language use a common neural network. How much the two systems share has yet to be precisely determined, but it is clear that they exhibit many similar properties and that there is some overlap in the brain structures in which they are processed.
I. Shared Characteristics of Language and Music
Both language and music have existed in every human society since the dawn of culture. Early instruments such as bone flutes, jaw harps, and some percussive instruments have been found dating back to as early as 30,000 years ago (19). An introductory linguistics text states, simply, “Wherever humans exist, language exists” (6). The neural correlates and evolutionary basis of these two systems is still a matter of investigation, but it seems clear that both systems have been a major part of human society for many thousands of years.
Most humans begin life with highly integrated perceptions of speech and music. In fact, Koelsch et al., of the Max Planck Institute of Cognitive Neuroscience and the Harvard Medical School Department of Neurology, point out that researchers have hypothesized that
music and speech are intimately connected in early life, that musical elements pave the way to linguistic capacities earlier than phonetic elements, and that melodic aspects of adult speech to infants represent the infant’s earliest associations between sound pattern and meaning (8).“Motherese” is the term for the musical style of speech which constitutes an infant’s first exposure to language. It is universally used by mothers while talking to their infants, and has been shown to be more effective than adult-to-adult speech in reducing crying and producing smiling and affectionate responses in babies (18). This mother-infant interaction may have an evolutionary basis, as it promotes bonding and parental commitment (18).
Normal adult speech also contains musical features. Prosody, or poetic meter, exhibits aspects of meter and melody. Just as music uses metric patterns to draw attention to melodic or harmonic elements, Kristeva et al. cite studies that indicate that word stress and stressed position in sentence structure lead to more rapid phoneme monitoring (9). Thus musical elements can play an important role in speech processing.
Both language and music also exhibit definite structures, or grammars. They are composed of analogous elements. Koelsch et al. argue that at the most basic level the interval relationships within a chord parallel the phonological relationships within a word (8). In fact, the superior temporal gyrus and the upper bank of the superior temporal sulcus, which have been identified as sites of phonemic processing, become activated in a series of chords modulating from one key to another. Whereas linguistic syntax combines words into phrases and sentences, musical syntax combines chords of various harmonic functions into meaningful musical phrases (2). One can even make an argument for the existence of a kind of musical semantics. In a recent study, Koelsch et al. found that Wernicke’s area, known to be intimately involved in processing the semantic content of language, was activated while participants listened to a series of chords involving modulations, tone clusters, and several instruments exhibiting a variety of timbres. The authors conclude that the activation of Wernicke’s area might signal the brain’s attempt to find a “meaning” for the musical deviations as they related to the preceding passage (8).
Much of modern linguistics is based on Noam Chomsky’s innateness hypothesis of Universal Grammar (UG), which states that all human languages are developed from an innate “blueprint” for language in the brain (6). Children learn a target language by setting the parameters of UG based on the linguistic input of their parents and other speakers. For example, children must determine the standard word order of their language: subject-verb-object, subject-object-verb, verb-subject-object, verb-object-subject, object-subject-verb, or object-verb-subject. These six possibilities for word order are termed the parameters of UG for word order.
Music also has an innate component, analogous to UG, which can be subdivided into four levels of analysis. As explained by Jay Dowling, in the Blackwell Handbook of Perception, the most basic system, the psychophysical scale, assigns perceived pitch to a continuum of sound frequencies (5). Tonal material is extracted from the psychophysical scale, and constitutes the set of pitches that can be used in the music of a particular culture. From the tonal material, each individual constructs the tuning system specified by his/her culture, that is, the pitches which form the basis for the scales used in tonal music. Finally, the modal scale, the only one of these somewhat abstract parameters commonly explicitly used among musicians, constitutes the pitches available for use in a melody.
These parameters of melodic content are culturally defined. Listeners become “acculturated” at an early age, according to Dowling, extracting the “pattern invariants of the musical system(s) of the culture” (5) from the musical stimuli in their environments. Dowling continues: “Acculturated listeners’ automatic perceptual habits lead them to hear music in a way appropriate to that particular culture” (5). This explains why Indian music sounds strange to Western listeners: Contrary to popular belief, Indian musicians don’t simply have different taste in music than Western musicians; rather they use completely different sets of pitches and scales. These constitute the grammar of Indian music, just as the linguistic rules of Hindi make up the grammar of the native language of many Indians.
II. Studies in Musical and Linguistic Perception
Similarities are also evident in perception of music and language. Both speech and music are processed in distributed areas of the auditory cortex, although the amount of overlap between the two processing systems is a matter of debate. In recent years, many studies have been conducted investigating the effect of music on linguistic processing and vice versa. Three studies—by Bigand et al. (2), researchers at Dartmouth College, the University of Bourgogne, and the University of Paris-Sorbonne; Poulin-Charronat et al. (15) of the University of Bourgogne and the University of Paris-Sorbonne; and Koelsch et al. (8)—used listening tasks involving harmonic sequences. Bigand et al. and Poulin-Charronat et al. explored the effects of harmonic priming on phonemic and semantic processing, respectively, while Koelsch et al. investigated the activation of neural networks during listening.
Bigand et al. examine the effects of harmonic priming on phoneme perception. Student participants, both musically trained (musicians) and with no formal musical training (non-musicians), were asked to identify the final phonemes in a sequence of chords sung on nonsense syllables as either /i/ or /u/ (2). Each of these chord sequences, of which there were twenty-four, were composed of eight chords of the same major key played on VocalWriter software. The first six chords of each established the global musical context (key), while the last two chords formed an authentic cadence, that is, a conclusive-sounding interval. The final chord was either a tonic chord (i.e. the root chord of the key) or subdominant (fourth chord of the scale), which were described as “related” and “congruent but less related,” respectively. The target chord never occurred in the preceding seven chords. The target chord was sung either on /di/ or /du/, and the participants had to determine quickly which syllable they heard.
Bigand et al. found that participants responded more quickly and with a higher percentage of accuracy (98.2% vs. 96.8%) when the final phoneme was sung on the tonic chord (related condition) than on the subdominant (congruent but less related condition) (2). These results indicate that harmonic priming influenced the perception of phonemes. This is particularly interesting since participants were only explicitly instructed to pay attention to the final syllable of the sequence, not to the harmonic structure. In fact, to determine the relationship of the target chord to the context (i.e. tonic or subdominant), the participant must first infer the key of the musical sequence. Nevertheless, a facilitation effect for phonemic processing occurred for the related condition but not for the congruent but less related condition. The authors conclude that harmonic priming occurs automatically (2). Furthermore, since musical context clearly affected linguistic perception in this experiment, they go on to suggest that
[h]armonic accents may influence phoneme monitoring in vocal music as prosodic cues influence phoneme monitoring in speech perception. . . . tonic target chords might act as stronger stressed events than subdominant chords, resulting in faster processing for the phonemes sung on the tonic rather than the subdominant chord (2).In a related study, Poulin-Charronat et al. discuss a similar phenomenon in terms of “attentional resources” (15). Since harmonic priming serves to focus attention in the case of a tonic chord, the linguistic content can be processed more rapidly. When a subdominant chord occurs, this facilitation effect is not as strong.
In this second study, four professional singers were recorded singing forty-eight simple sentences on eight-chord sequences. Each sentence ended in a word related to the semantic context, i.e. “The giraffe has a very long neck;” a moderately semantically related word, as in “The giraffe has a very long foot;” or a non-word, for example, “The giraffe has a very long keck” (15). As in the previous experiment, each sequence ended either on the tonic chord or subdominant chord. For each sequence, listeners had to quickly decide whether the final syllable was a word or a nonsense syllable (like “keck”). The intent was to investigate the interference of harmonic structure with the processing of linguistic information at the level of semantics (15).
The results for semantic processing were similar to those obtained in the case of phonemic processing. The element of semantic priming in the context of the sentence was shown to be more pronounced when the target chord was the tonic than when it was the subdominant (15). There were more correct responses, and shorter response times, for semantically related words than for less related words, and for words sung on the tonic than those on the subdominant. Thus, the authors conclude that the semantic and harmonic contexts were both involved in target word processing (15).
Again, the element of implicit processing is significant. Poulin-Charronat et al. go on to argue that “[t]he fact that musical context modulates a linguistic computation in which the participants were explicitly engaged suggests that musical structure is processed in an automatic and irrepressible way” (15). The authors speculate that the differing of their results from those of similar experiments, which found more dissociation between musical and linguistic processing, may have been caused by others’ use of explicit comparison of language and music. For example, Bonnel et al. (2001) found evidence for distinct semantic and musical processing in vocal music in a study in which they explicitly instructed participants to pay attention to both musical and semantic incongruities. Poulin-Charronnat et al. claim:
Explicit tasks usually require participants to focus attention only on one type of violation. Implicit tasks, by contrast, tap into processes that are mostly associative by nature. As a consequence, representations probed by implicit tasks are made of insecable chunks of knowledge that are not articulated into well-defined subunits. Implicit tasks, thus, are less likely to bias participants toward analytic processing of the one or the other structure than explicit tasks (15).Furthermore, they contend that while experiments involving such explicit tasks have found evidence of semantic/musical dissociation, no study using purely implicit tasks has yet done so (15).
Some research suggests that an entire cortical network previously thought to be language-exclusive serves in the processing of music. Koelsch et al. used fMRI to investigate the activation of various brain areas while participants listened to a series of recorded harmonic sequences, strung together to resemble a musical piece, played on a piano (8). Participants were asked to push a button whenever they detected a switch from the piano to another instrument. In between these responses tone clusters and key modulations occurred in the harmonic sequence. When a deviant instrument was detected, participants were to push the left-hand button if they had heard a tone cluster since the last response, and the right-hand button if no tone cluster had occurred.
The researchers found that an extensive cortical network, including Broca’s and Wernicke’s areas, the superior temporal sulcus, Heschl’s gyrus, planum polare, planum temporale, and the anterior superior insular cortices, was activated during the task (8). Most of these areas are intimately involved in language processing, and while many have been shown to be involved in other types of processing as well, the system as a whole has been thought to be language-specific. Thus, the authors conclude, these findings suggest that this linguistic neural network serves a broader range of functions than has previously been supposed (8).
A distinction that they believe accounts for these novel results is their use of multi-part, rather than melodic, stimuli. The authors claim this is significant because harmonized melodic tones contain a great deal more harmonic information than a single melodic tone (8), necessitating more complex, linguistic-like processing.
These three studies represent only a fraction of the research recently published in this area. In general, this research points to a high degree of integration in musical and linguistic processing. While the scope of the implications of these findings remains unclear, studies have already been conducted in the use of music therapy to improve communication skills (11). Another study shows that musicians exhibit a significant increase in gray matter density in Broca’s area. The authors conclude that musical performance is a factor in mitigating the negative effects of aging on the brain (16). Clearly, these and other findings reflecting the positive effect of music on linguistic processing merit further investigation.
Works Consulted
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