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Ilie indlvidual rcmains stahlc within his cnvironment; whereas, with body transport, the individual is moving in his cnvironnicnl. Each of thesc catcgories can potentially occur in the presence or absence of manipulation (ie. skilled use of upper or lower extremities).

Bascd on cnvironmcntal context, we can distinguish betwecn open. inlcrmediate and closcd tasks. Tlić simplcst lasks are closed tasks. Thcse are tasks in which regulatory stimuli -are slabie and predictable and thcre is no variability belween trials. An examplc of a closed task would be transitioning front sit to stand front a dining roont chair. The most contplex tasks are open lasks. These are tasks in which the regulatory stintuli are ntoving and vary front trial to trial. Moving to catch a bali which is thrown randomly is an exantple of an open task. Inlcrmediate lasks are lhosc for which the regulatory stintuli are not moving but vary front trial to trial. Thcre are ntany options for providing variability belween trials. for example, you ntighl vary the support surlace or the size and weight of what you are manipulating. Transitioning front sit to stand front a variety of diffcrent types of chairs is an exantplc of an intermediate task.

In sumntary. for closed tasks, motor behaviors leading to task completion are very sintilar from trial to trial. For intermediate and open tasks. greater diversity in motor slratcgies is needcd to insure successful task completion over trials.

Table 1:1 Therapeutic activities using the Swiss bali in relation to Gentile's Taxonomy of tasks (Gentile, 1972).

MOVEMENT FUNCTION

	BODY STA8ILITY	BODY STABILITY PLUS MANIPULATION	BODY TRANSPORT	BODY TRANSPORT PLUS MANIPULATION
CLOSED	Sil on a mai	Sil on a mai and reach with the bali in your hands towards a stationary target	Sit <-*>Siand from a mat	Sil <~>Stand holding onto a bali
INTERMEDIATE: STATIONARY ENVIRONMENT WITH INTERTRIAL VARIA8ILITY	Sit on a mat versus on a chair versus on a bench	Sil on a mat and reach for different size balls	Sil <-->Stand from a variety of chairs	Sil <~>Sland from various chairs holding onlo differenl sized balls each trial
OPEN	Sitling on a bali	Sitting on a bali doing a PRE program with UEs	Sil <-->Stand from a bali	Sit <->Stand from a bali lo catch a thrown object

©1995 by Joannę Posner-Mayer, PT

Genlile's iheoretical framework is useful in reminding us of categories of movcnicnl and environmen(al contcxts Ihat often escape our altcmion in dcsigning our ircalmenls. Williin Ihc taxonomy, Ihc complcxity of lasks increases from the leasl contplcx (closed lasks. body stabilily, without manipulation) to Ihc most complex (open tasks, body Iranspori willi manipulation). For our paliems. the ability to cope in stationary invariant environmcnts is ncccssary but not suffident if we consider the high degrec of variability prcsent in rcal lite situations. A dinic therapist who only provides excrcisc training lying on a mat or ambulation training williin the physical therapy gym will not adequatcly prepare the patient to copc with Ihc information proccssing demands placcd upon the same patient wlicn ambulating along a busy Street.

The bali allows us to rehabilitate all categories of movcmcnt williin Genlile's classificution. Using the bali ntakes available a variety of practicc conditions lliat vary in difficully. from skills tliat emphasize body stabilily with manipulation in stationary cnvironmcntal conditions (sec closed lasks. Table i.l) to skills involving body mobility and manipulation in cnvironmental conditions wlicre regulatory stintuli are moving and change from trial to trial (sec open lasks. Table I.l). Any task performed in weight bearing on the bali is characterized by variabilitv from moment to moment bccause the hall is an unstable base of support and never rcaels cxaclly the same way lwice. Different size. firmness. and weights of balls enhancc variability belween trials. Uppcr extrcmily rangę of niotion and strengthening activities may be mado morę funclional il tliey incorporate manip-ulation and placing activities with balls. Information proccssing. particularly responsc sclection and rapid reaction linie esscntial to success in open tasks. is challenged when the patiem musi trap a mov-ing bali or glide from side-lo-sidc across a bali (sce 8:12).

Motor Lear ni ng

Motor learning or rclearning is key to establishing or restoring oplimal nunement patterns. Tlić devclopment of dysfunction and palhology from nunement imhalancc is a well-acceptcd principle in neurological rchabililation. Even in indhiduals without signiticant neuro-logical impairmcnl, the production of faulty nunement patterns has bcen suggested to contrihute to the development of dysfunction and pathology. Instruction in proper nunement patterns has bcen suggested as a key element in promoting biomechanically sound and cITicient niovcmenls [Sahrmann. S. 1987).

Motor skill acquisition is thought to occur in stages [Fitts. 1964; Gentile. 1972). In generał, the early stages are thought to be highly cognitnc. require conscious attention. and vcrbal cues are often used to direct or prompt performance. Feedback is important in the early stages to evaluate Ihc success of the motor slralcgy used in relation to the expccled and aclual task outeome. As practicc continues, the learned behavior becomcs morę automatic in naturę. rcquiring less conscious monitoring, less direction of our attention, and less examination of feedback. nicrc is an incrcase in the ease and efficiency with which the movcments are executcd. As the learned skill becomcs morę automatic, it may be possible for the learner to engage in other hchaviors simultancously without cxperiencing a deterioration in the former behavior. Gentile has used the terms"fucation" in refer-ring to learning which narrows the rangę of performance oulcomcs resulting in incrcascd consistency of performance (eg. signing one's name); and "diversification" to describc Ihc acąuisition of a morę flcxible motor strategy that is ąuickly adaptable to changing regulatory environmental conditions (eg. sitting on a hall and drawing the letters of the alphabel with your foot. Sec chapter 6:14),

© 1995 by Joannę Posner-Mayer, PT 13