Workload : the subtle harmony between preparation and performance

In com­pe­ti­tions, all that seems to mat­ter is the end result : the per­for­mance in front of an audience. But achie­ving this result requires pre­pa­ra­tion. More and more research is being car­ried out to gain a bet­ter unders­tan­ding of athlete’s bodies and the pre­pa­ra­tion pro­cesses invol­ved. Today, in the world of top-level sport, eve­ry move­ment is scru­ti­ni­sed and eve­ry vic­to­ry is the result of hard work and meti­cu­lous preparation.

This has given rise to the concept of work­load. “Over the last few years, there has been an expo­nen­tial increase in the num­ber of scien­ti­fic publi­ca­tions on this concept,” explains Jacques Prioux, uni­ver­si­ty pro­fes­sor at École Nor­male Supé­rieure in Rennes. This is where the real bat­tle lies, in the meti­cu­lous mana­ge­ment of work­load ; a deli­cate balance to be struck bet­ween impro­ving spor­ting per­for­mance and pre­ser­ving the athlete’s phy­si­cal integrity. 

“There are two types of work­loads : exter­nal and inter­nal,’ he explains. Ove­rall, the exter­nal work­load is most often quan­ti­fied using sen­sors (GPS, LPS, etc.). It cor­res­ponds to the objec­tive mea­su­re­ment of the work done by the ath­lete during trai­ning or com­pe­ti­tion. The inter­nal work­load cor­res­ponds to the body’s indi­vi­dual res­ponse to the demands impo­sed by the exter­nal load. It can, for example, be quan­ti­fied using dif­ferent phy­sio­lo­gi­cal and/or bio­lo­gi­cal para­me­ters.” To ensure that the ath­lete is in the best pos­sible phy­si­cal condi­tion, it is impor­tant to stu­dy the rela­tion­ship bet­ween the exter­nal work­load and the work­load spe­ci­fic to the ath­lete, the inter­nal workload.

To observe and unders­tand exter­nal work­load, resear­chers need to ana­lyse the ath­letes’ acti­vi­ty during trai­ning and com­pe­ti­tion. “Tech­no­lo­gy plays a very impor­tant role,” admits the pro­fes­sor. It is through tech­no­lo­gy, and all the tools it offers us, that we can car­ry out moni­to­ring.” Various sen­sors, such as the GPS (glo­bal posi­tio­ning sys­tem) for out­door sports (foot­ball, rug­by, etc.) and the LPS (local posi­tio­ning sys­tem) for indoor sports (hand­ball, vol­ley­ball, etc.), enable extre­me­ly pre­cise ana­ly­sis of the ath­letes’ acti­vi­ty. How far have they run ? At what speed ? How many acce­le­ra­tions ? Dece­le­ra­tions ? And so on. “The clo­ser we get to the top level, the more cru­cial this infor­ma­tion becomes,” he insists. “I am cur­rent­ly super­vi­sing a the­sis in which we’re wor­king on data from players from Brest-Bre­tagne Hand­ball, i.e. the highest level in women’s hand­ball in Europe. They are all equip­ped with iner­tial units (ano­ther avai­lable sen­sor) during training.”

In this way, it is pos­sible to pre­ci­se­ly ana­lyse the work car­ried out by an ath­lete during trai­ning. This makes for much more opti­mal pro­gram­ming. “It would be just as valuable to obtain the same data in com­pe­ti­tion condi­tions,” admits Jacques Prioux. “Howe­ver, the cost of equip­ping sta­diums, gym­na­siums and players with these tech­no­lo­gies is very high.” This data, although impor­tant, remains worth­less unless it is consi­de­red in rela­tion to the impact of this Work­load on the ath­lete in ques­tion. “Work­load is only of inter­est if we stu­dy its rela­tion­ship with per­for­mance, but also with poten­tial inju­ries,” he insists.

It’s a well-esta­bli­shed fact that eve­ry single body is dif­ferent. The same work­load may not feel the same to eve­ryone. And each body will require dif­ferent pre­pa­ra­tion to opti­mise per­for­mance while limi­ting inju­ries. That’s why ana­ly­sing inter­nal work­load is so impor­tant, and there are many tools avai­lable to resear­chers to enable this to be quan­ti­fied. “At the end of a group hand­ball trai­ning ses­sion, for example, we ask the players to assess the level of dif­fi­cul­ty of the ses­sion on a scale of 1 to 10,” explains the pro­fes­sor. “If one player marks the ses­sion at 5, while ano­ther marks it at 10, we alrea­dy have an impor­tant point of com­pa­ri­son : the state of fit­ness of the two players is pro­ba­bly not the same.”

In this example, for an exter­nal work­load consi­de­red to be simi­lar, the fee­ling dif­fers bet­ween the two players. This data can then be cou­pled with other phy­sio­lo­gi­cal data, such as oxy­gen consump­tion, heart rate or lac­tic acid concen­tra­tion, to objec­ti­vise the effort made during training. 

In this context, the dose cor­res­ponds to the work­load and the res­ponse cor­res­ponds to per­for­mance or inju­ry. Theo­re­ti­cal­ly, if the work­load pro­po­sed is too low, the athlete’s level of fit­ness will pro­ba­bly be lower than that obtai­ned with a higher work­load. Howe­ver, too high a work­load can have nega­tive effects on the athlete’s body, in terms of fatigue for example. The dif­fi­cul­ty the­re­fore lies in iden­ti­fying and then using the right work­load. “If the work­load pro­po­sed during trai­ning is too high, the fatigue level incur­red will also be high,” explains Jacques Prioux. “The risk is that you won’t improve your ini­tial level of per­for­mance and you’ll end up with an inju­ry. If the work­load pro­po­sed during trai­ning has been cor­rect­ly adap­ted, the fatigue level will allow opti­mal reco­ve­ry, favou­ring an impro­ve­ment in your ini­tial level of per­for­mance and redu­cing the risk of injury.” 

This dose-res­ponse rela­tion­ship is the sub­ject of a great deal of scien­ti­fic research, par­ti­cu­lar­ly using arti­fi­cial intel­li­gence. The aim of this scien­ti­fic work is to model this dose-res­ponse rela­tion­ship and pro­vide coaches with tools to help them plan and indi­vi­dua­lise the trai­ning they offer their ath­letes. “There is still a great deal of pro­gress to be made in this area, but the goal looks increa­sin­gly achie­vable,” concludes the professor.

Pablo Andres